Unity vs Bevy

Agent access

1. ai-native userPoint an agent at llms.txt or agent-oriented docs

   weight 2 · round to Unity
   Unity~partialprobed5/10

   unity.com serves a root llms.txt file (unity-docs-15, unity-docs-16, unity-probe-rt-2) that an agent could be pointed at, but the actual technical documentation site (docs.unity3d.com) returns 404 for llms.txt and has no markdown mirrors of manual pages (unity-probe-1, unity-probe-2, unity-probe-rt-2), so agent-oriented docs coverage is only marketing-site-deep. missing for 10: llms.txt or agent-readable docs covering the actual API/manual reference (docs.unity3d.com), evidence of agents successfully consuming these docs in practice.

   • [claimed-docs] “Unity’s free plan, Unity Personal, is for individuals and small organizations with less than $100K of revenue and funds raised in the last 1…”
   • [claimed-docs] “Create and optimize high-end games and interactive experiences. Bring your team’s vision to life with Unity’s real-time development platform…”
   • [probe] “PROBE runtime (recorded 2026-09-15): unity.com serves a site-root llms.txt ('# Unity — Develop, deploy, and grow with Unity...'), but docs.u…”
   • [probe] “PROBE llms.txt: HTTP 404 at https://docs.unity3d.com/llms.txt”
   • [probe] “PROBE docs-md: HTTP 404 at https://docs.unity3d.com/Manual/index.html.md”

   proof ↗⚑ flag

   Bevy—none0/10

   Direct probes confirm no llms.txt exists (404) and no agent-oriented docs endpoint is served; docs.rs/crates.io provide standard human docs but nothing tailored for agent consumption per the story.

   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”
   • [probe] “PROBE docs-md: HTTP 404 at https://bevy.org/learn/.md”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”

   proof ↗⚑ flag

2. ai-native userRun the product headlessly / in CI for automation

   weight 2 · round to Unity
   Unity✓fullprobed8/10

   Unity's Editor and Player support extensive command-line arguments (unity-docs-6, unity-docs-7) including an explicit headless mode with no display/input (unity-docs-8), enabling automation and CI pipelines; Unity Hub is also installable headlessly via package managers (unity-probe-rt-3), supporting real-world CI build setups. One community report notes cost barriers to setting up a CI build server (unity-comm-13), but this is a licensing/cost complaint rather than a technical failure of headless capability. Missing for 10: independent hands-on verification of a full CI pipeline example and more detail on batchmode build automation scripts.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity Hub installs keylessly from Homebrew (cask unity-hub 3.21.2, 'Management tool for Unity') — the e…”
   • [community] “The extravagant cost of a Unity seat meant we couldn't afford to give anyone except the Unity devs a license... For the same reason, we coul…”

   proof ↗⚑ flag

   Bevy—none0/10

   The evidence pack contains no mention of headless mode, CI integration, or automated/scripted execution of Bevy apps; only rendering, ECS, editor-live-reload and general community sentiment are covered. Running headless in CI is a reasonable ask for a game engine, but nothing in the pack demonstrates it.

   ⚑ flag

3. ai-native userConnect an agent via an official MCP server

   weight 3 · round to Unity
   Unity~partialprobed6/10

   Unity ships an official MCP server (unity-mcp-get-started docs, unity.com/features/ai 'View MCP Docs') bundled in the com.unity.ai.assistant package, letting agents connect to the Editor. However it's beta, closed-source with no public repo or standalone package (no keyless handshake), and AI usage is metered via Unity Credits, while the much larger community MCP (CoplayDev/unity-mcp, 14k+ stars) suggests the official one is not the primary integration path. Missing for 10: open-source/self-hostable server, GA (non-beta) status, broader independent adoption evidence of the official server itself.

   • [probe] “official MCP server documented at https://docs.unity3d.com/Packages/com.unity.ai.assistant@latest/index.html?subfolder=/manual/integration/u…”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [claimed-docs] “Whenever you generate an image, create a 3D model, produce a sound effect, or send a message to the Assistant, you spend Unity Credits from …”

   proof ↗⚑ flag

   Bevy—none0/10

   Bevy is a game engine/library, not itself an AI agent, so an MCP server axis applies as a fair question, but evidence explicitly shows no official MCP server exists — only nascent third-party tooling (bevy_brp) built on the Bevy Remote Protocol. No official MCP server is documented.

   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”
   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”

   proof ↗⚑ flag

4. ai-native userUse an official CLI

   weight 2 · round to Unity
   Unity✓fullprobed7/10

   Unity ships a well-documented official CLI for the Editor and Player, supporting batch/headless mode, custom arguments, and automated build workflows (unity-docs-6/7/8/9, unity-probe-5), which is exactly the kind of scriptable interface an AI agent could drive for CI/automation. Missing for 10: no AI-specific CLI tooling and the docs aren't machine-readable (llms.txt/.md mirrors 404 per unity-probe-rt-2), limiting direct agent ingestion of the CLI reference itself.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “Unity can build your application for different platforms with unique build configurations using build profiles in the Unity Editor.”
   • [probe] “official CLI documented at https://docs.unity3d.com/Manual/EditorCommandLineArguments.html”
   • [probe] “PROBE runtime (recorded 2026-09-15): unity.com serves a site-root llms.txt ('# Unity — Develop, deploy, and grow with Unity...'), but docs.u…”

   proof ↗⚑ flag

   Bevy—none0/10

   No evidence of an official Bevy CLI tool anywhere in the evidence pack; only cargo (Rust's generic build tool) and community projects like bevy_brp are mentioned, not a first-party CLI for AI-native workflows.

   ⚑ flag

5. ai-native userDrive the product through a documented public API

   weight 3 · round to Unity
   Unity✓fullprobed8/10

   Unity ships an extensively documented public Scripting API for editor/runtime automation, plus documented command-line/batchmode interfaces for headless CI-driven builds, and an official MCP server (com.unity.ai.assistant) explicitly for AI-driven control of the editor, corroborated by community MCP adoption. This goes beyond a typical closed product and gives AI-native users multiple documented, programmatic entry points. Missing for 10: a formal OpenAPI/REST spec (docs.unity3d.com openapi probes 404) and independent hands-on validation of the MCP server's completeness.

   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [probe] “official MCP server documented at https://docs.unity3d.com/Packages/com.unity.ai.assistant@latest/index.html?subfolder=/manual/integration/u…”
   • [probe] “official CLI documented at https://docs.unity3d.com/Manual/EditorCommandLineArguments.html”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity Hub installs keylessly from Homebrew (cask unity-hub 3.21.2, 'Management tool for Unity') — the e…”

   proof ↗⚑ flag

   Bevy~partialprobed5/10

   Bevy ships a documented Rust API (in-depth reference docs, docs.rs) and even a first-party 'Bevy Remote Protocol' that a nascent community tool (bevy_brp) uses to drive the engine externally, but there is no AI-oriented public API surface: no llms.txt, no OpenAPI/swagger spec, and no official MCP server, and the remote-protocol tooling is described as nascent/community-only rather than a robust public API for programmatic driving. Missing for 10: an official machine-readable API spec (OpenAPI/llms.txt), first-party remote-control docs beyond community wrappers, and evidence of stable AI-agent usage against the API.

   • [claimed-docs] “Learn how to use Bevy's types, traits and methods using the in-depth reference documentation, complete with inline examples.”
   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”
   • [probe] “PROBE openapi: all candidate paths 404 (https://bevy.org/openapi.json, https://bevy.org/swagger.json, https://bevy.org/api/openapi.json, htt…”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”

   proof ↗⚑ flag

6. ai-native userBuild against official SDKs

   weight 2 · round to Unity
   Unity✓fullprobed7/10

   Unity documents extensive official SDK-style surfaces: the public Scripting API for direct C# integration (unity-docs-11), the Package Manager ecosystem for extending functionality (unity-docs-13), editor extensibility APIs (unity-docs-10), and CLI/automation hooks for headless and CI workflows (unity-docs-6,7,8,9, unity-probe-5). It also ships an official MCP server for AI-assistant integration (unity-probe-4, unity-probe-rt-1), directly relevant to AI-native usage, though distribution is closed (no public repo) and metered via credits rather than a keyless open SDK. Missing for 10: no dedicated multi-language SDK page, no OpenAPI/REST spec (probes show 404s), and no llms.txt/markdown mirror on the actual docs site (only on unity.com marketing pages).

   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”
   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Unity can build your application for different platforms with unique build configurations using build profiles in the Unity Editor.”
   • [probe] “official MCP server documented at https://docs.unity3d.com/Packages/com.unity.ai.assistant@latest/index.html?subfolder=/manual/integration/u…”
   • [probe] “official CLI documented at https://docs.unity3d.com/Manual/EditorCommandLineArguments.html”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [probe] “PROBE runtime (recorded 2026-09-15): unity.com serves a site-root llms.txt ('# Unity — Develop, deploy, and grow with Unity...'), but docs.u…”

   proof ↗⚑ flag

   Bevy~partialprobed6/10

   Bevy itself ships as an official, versioned Rust SDK (the `bevy` crate on crates.io) with first-party API reference docs, quick-start guides, and migration guides, which is what an AI-native developer would build against (bevy-docs-21, bevy-docs-27, bevy-docs-15, bevy-probe-rt-1). However, pre-1.0 status with breaking changes on nearly every release, community complaints about docs being thin once you leave the intro book, and confirmed absence of llms.txt/AI-consumable doc formats make it harder for AI agents to reliably target the 'official SDK' surface (bevy-probe-rt-1, bevy-comm-12, bevy-comm-14, bevy-probe-1, bevy-probe-rt-2). Missing for 10: llms.txt/AI-friendly doc export, stability guarantees across versions, and independent evidence of AI agents successfully building against the SDK.

   • [claimed-docs] “Bevy is just a normal Rust dependency. You can either add it to an existing Rust project or create a new one.”
   • [claimed-docs] “Learn how to use Bevy's types, traits and methods using the in-depth reference documentation, complete with inline examples.”
   • [claimed-docs] “Every Bevy update brings new functionality and improvements. Follow these guides to migrate your project to the latest Bevy has to offer!”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”
   • [community] “Things have started to stabilize, but unless you're willing to get your hands dirty and deal with regular breaking changes, I don't yet reco…”
   • [community] “I'm put off by the limited docs. I've read the Bevy book, only takes a few minutes, and just like that I'm out of resources to turn to when …”
   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”

   proof ↗⚑ flag

Agentic features

1. ai-native userGet AI-generated insights and suggestions from my data inside the product

   weight 2 · round to Unity
   Unity~partialprobed5/10

   Unity ships an in-editor AI Assistant (part of com.unity.ai.assistant, metered via Unity Credits) that can chat, generate images/3D models/sound effects, suggesting some AI-driven help inside the editor, and this is corroborated by a live MCP integration for the Assistant. However, evidence never shows the Assistant producing analytical 'insights' from a user's own project data (e.g., analytics, performance suggestions) — it's framed as generative-content assistance rather than data-driven insight generation. Missing for 10: dedicated documentation of data-analysis/insight features, independent hands-on validation of insight quality, and detail beyond generic 'send a message to the Assistant.'

   • [claimed-docs] “Whenever you generate an image, create a 3D model, produce a sound effect, or send a message to the Assistant, you spend Unity Credits from …”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [probe] “official MCP server documented at https://docs.unity3d.com/Packages/com.unity.ai.assistant@latest/index.html?subfolder=/manual/integration/u…”

   proof ↗⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

2. ai-native userSet up automations that run autonomously in the background

   weight 2 · round to Unity
   Unity~partialprobed5/10

   Unity supports background/unattended automation via documented CLI and headless-mode Editor/Player flags for CI-style builds (unity-docs-6/7/8, unity-probe-5, unity-probe-rt-3), and it also ships an official (beta) MCP server for AI-assistant integration (unity-probe-rt-1) that could drive agentic workflows. However, there's no evidence of built-in scheduling, triggers, or a persistent agent-orchestration layer — automation still requires external CI tooling or scripting rather than a native 'set-and-forget' automation feature. Missing for 10: native scheduling/trigger system, documented autonomous agent workflows beyond beta MCP, independent hands-on confirmation of unattended background runs.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [probe] “official CLI documented at https://docs.unity3d.com/Manual/EditorCommandLineArguments.html”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity Hub installs keylessly from Homebrew (cask unity-hub 3.21.2, 'Management tool for Unity') — the e…”

   proof ↗⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

3. ai-native userDelegate tasks to a built-in AI assistant inside the product

   weight 3 · round to Unity
   Unity~partialprobed6/10

   Unity docs confirm a built-in AI Assistant (com.unity.ai.assistant) that lets users generate images, 3D models, sound effects, and chat with the Assistant directly inside the Editor, metered via Unity Credits — a genuine in-product AI delegate. However, the feature is explicitly beta, evidence is thin on scope/reliability, and no independent/hands-on corroboration of its usefulness exists. Missing for 10: independent hands-on validation of the Assistant's task quality, detail on task scope/limits beyond asset generation, and confirmation it is GA rather than beta.

   • [claimed-docs] “Whenever you generate an image, create a 3D model, produce a sound effect, or send a message to the Assistant, you spend Unity Credits from …”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”

   proof ↗⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

4. ai-native userOperate the product with natural-language commands

   weight 2 · round to Unity
   Unity~partialprobed6/10

   Unity ships an official AI Assistant that accepts natural-language messages (consuming Unity Credits per message) and an official MCP server (beta) integrated into the Editor, per unity-docs-14 and unity-probe-rt-1, showing genuine natural-language operation of the tool. However this is explicitly beta, credit-metered, has no public/open repo (closed distribution), and there's no independent hands-on evidence of its reliability compared to the much larger community MCP project. Missing for 10: independent/hands-on validation of the Assistant's command execution, GA (non-beta) status, and documentation of the scope of natural-language commands it can actually perform.

   • [claimed-docs] “Whenever you generate an image, create a 3D model, produce a sound effect, or send a message to the Assistant, you spend Unity Credits from …”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [probe] “official MCP server documented at https://docs.unity3d.com/Packages/com.unity.ai.assistant@latest/index.html?subfolder=/manual/integration/u…”

   proof ↗⚑ flag

   Bevy—none0/10

   Bevy is a Rust game engine/library with no evidence of any natural-language command interface; probes confirm no llms.txt, no MCP server, and only nascent third-party remote-protocol tooling (bevy_brp), not a natural-language control layer.

   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”
   • [probe] “PROBE docs-md: HTTP 404 at https://bevy.org/learn/.md”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”

   proof ↗⚑ flag

Api quality

1. ai-native userExplore an interactive API reference with runnable examples

   weight 2 · round to Bevy
   Unity—none0/10

   The docs manual and scripting reference exist, but there's no evidence of an interactive API reference with runnable/executable code examples — probes explicitly show no OpenAPI spec, no llms.txt/docs-md mirrors at docs.unity3d.com, and no interactive sandbox is mentioned anywhere in the pack.

   • [probe] “PROBE openapi: all candidate paths 404 (https://docs.unity3d.com/openapi.json, https://docs.unity3d.com/swagger.json, https://docs.unity3d.c…”
   • [probe] “PROBE docs-md: HTTP 404 at https://docs.unity3d.com/Manual/index.html.md”
   • [probe] “PROBE llms.txt: HTTP 404 at https://docs.unity3d.com/llms.txt”
   • [probe] “PROBE runtime (recorded 2026-09-15): unity.com serves a site-root llms.txt ('# Unity — Develop, deploy, and grow with Unity...'), but docs.u…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”

   proof ↗⚑ flag

   Bevy~partialprobed5/10

   Bevy advertises 'in-depth reference documentation, complete with inline examples' and a separate gallery of wasm-compiled examples that run directly in the browser, giving some interactive/runnable exploration of the API surface. But these are two disconnected resources rather than a unified interactive API reference, docs.rs is static/crawlable with no live-run capability, and there's no llms.txt, MCP, or agent-facing interactive console. Missing for 10: a single integrated interactive reference (e.g. rustdoc playground-style 'run' buttons on API docs), agent-facing tooling (llms.txt/MCP) to programmatically explore it, and independent confirmation the wasm examples are tied to the API reference itself.

   • [claimed-docs] “Learn how to use Bevy's types, traits and methods using the in-depth reference documentation, complete with inline examples.”
   • [claimed-docs] “Browse bevy examples compiled to wasm and running directly in your browser!”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”
   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”

   proof ↗⚑ flag

2. ai-native userDownload a machine-readable API spec (OpenAPI or equivalent)

   weight 2 · round drawn
   Unity—none0/10

   Unity is a game engine/editor, not an API-driven service, but the story asks specifically about a machine-readable API spec (OpenAPI or equivalent); probes explicitly confirm none exists — all candidate OpenAPI/Swagger paths return 404 and there is no llms.txt or docs-md mirror on the documentation domain. Since Unity does expose scripting/editor APIs and even MCP tooling, this axis is applicable to its ecosystem but the evidence shows the specific artifact is absent.

   • [probe] “PROBE openapi: all candidate paths 404 (https://docs.unity3d.com/openapi.json, https://docs.unity3d.com/swagger.json, https://docs.unity3d.c…”
   • [probe] “PROBE llms.txt: HTTP 404 at https://docs.unity3d.com/llms.txt”
   • [probe] “PROBE docs-md: HTTP 404 at https://docs.unity3d.com/Manual/index.html.md”
   • [probe] “PROBE runtime (recorded 2026-09-15): unity.com serves a site-root llms.txt ('# Unity — Develop, deploy, and grow with Unity...'), but docs.u…”

   proof ↗⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

3. ai-native userTest against a sandbox environment without touching production data

   weight 1 · round drawn
   Unity—none0/10

   No evidence describes a sandbox/test environment for Unity's AI/MCP tooling that isolates test data from production; the pack only covers general Unity engine features, pricing controversy, and MCP server existence with no mention of sandbox vs. production data separation.

   ⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

4. ai-native userRely on versioned APIs with a documented deprecation policy

   weight 2 · round to Bevy
   Unity—none0/10

   Evidence shows Unity exposes scripting/editor APIs and packages (unity-docs-11, unity-docs-13) but nothing documents a versioning scheme or deprecation policy for these APIs, and probes show no OpenAPI spec or machine-readable API docs (unity-probe-3, unity-probe-2). Missing for 10: any documented API versioning scheme, deprecation notices/timelines, or changelog policy for Unity's scripting/runtime APIs.

   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”
   • [probe] “PROBE openapi: all candidate paths 404 (https://docs.unity3d.com/openapi.json, https://docs.unity3d.com/swagger.json, https://docs.unity3d.c…”
   • [probe] “PROBE docs-md: HTTP 404 at https://docs.unity3d.com/Manual/index.html.md”

   proof ↗⚑ flag

   Bevy!disputedcontradicted3/10

   Bevy publishes migration guides for each release (bevy-docs-15) implying some versioning discipline, but there is no documented deprecation policy, and hands-on evidence shows the API is pre-1.0 with frequent breaking changes each release requiring real rework (bevy-comm-12, bevy-comm-13, bevy-probe-rt-1), directly undercutting reliability for an AI agent trained on prior APIs. Missing for 10: an explicit deprecation/versioning policy document, semver guarantees, and evidence that breaking changes are flagged/deprecated before removal rather than silently changed.

   • [claimed-docs] “Every Bevy update brings new functionality and improvements. Follow these guides to migrate your project to the latest Bevy has to offer!”
   • [community] “Things have started to stabilize, but unless you're willing to get your hands dirty and deal with regular breaking changes, I don't yet reco…”
   • [community] “On the last update 0.10 -> 0.11, I had to make quite a few changes on my app, but this time it compiled out of the box!”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

Agent editor

1. ai-native userAn agent can drive the editor and project programmatically — create scenes and nodes, edit properties, trigger builds — through a documented scriptable interface

   weight 3 · round to Unity
   Unity✓fullprobed8/10

   Unity documents a comprehensive scripting/editor extension API (custom inspectors, EditorWindows, AssetDatabase, Package Manager) plus command-line/headless automation for builds (unity-docs-6/7/8/9/10/11/12/13), and ships an official MCP server for AI agents inside the com.unity.ai.assistant package with a dedicated get-started manual page (unity-probe-4, unity-probe-rt-1), reinforced by a large third-party community MCP server (14k+ stars) enabling agent-driven scene/property/build workflows. Missing for 10: no public repo/keyless access to the official MCP server (closed distribution, credit-metered) and no independent hands-on verification of an agent actually creating scenes/nodes end-to-end via the documented interface.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Unity can build your application for different platforms with unique build configurations using build profiles in the Unity Editor.”
   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “The Asset Database stores information about the original source asset files and their imported counterparts to keep the two sets of data in …”
   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”
   • [probe] “official MCP server documented at https://docs.unity3d.com/Packages/com.unity.ai.assistant@latest/index.html?subfolder=/manual/integration/u…”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”

   proof ↗⚑ flag

   Bevy~partialprobed3/10

   Bevy has a first-party Bevy Remote Protocol that could support programmatic scene/entity manipulation, and a community tool (bevy_brp) built on it, but there is no official documentation, no llms.txt, and no official MCP server — the community tooling itself is described as nascent (70 stars). Since Bevy is a code-first Rust crate, most 'scripting' is done by writing/recompiling Rust code rather than through a documented runtime scriptable interface for driving an editor. Missing for 10: first-party documented API/schema for the Remote Protocol, official MCP or agent-facing tooling, evidence of hands-on agent use creating scenes/nodes and triggering builds via that interface.

   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”
   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”
   • [claimed-docs] “Create, save, and load ECS worlds using Bevy's Scene system”

   proof ↗⚑ flag

Codegen

1. ai-native userLLM-generated code mostly works on the first try — stable, well-documented APIs with abundant public examples the models have seen

   weight 2 · round to Bevy
   Unity—none0/10

   The evidence pack contains no data on LLM code-generation success rates, model familiarity with Unity's C# API, or first-try correctness of AI-generated scripts — only general docs, pricing drama, and MCP/CLI tooling notes. Without concrete evidence (docs, benchmarks, or community reports) speaking to this axis, it cannot be credited.

   ⚑ flag

   Bevy!disputedcontradicted4/10

   Bevy has abundant examples and reference docs (bevy-docs-16, bevy-docs-22, bevy-docs-27) which help LLM familiarity, but concrete community evidence shows the API is unstable pre-1.0 with breaking changes almost every release, requiring real migration work each time (bevy-comm-12, bevy-comm-13, bevy-probe-rt-1) — meaning LLMs trained on older versions likely generate code that fails to compile against current APIs. Docs are also reported as thin/outdated relative to the pace of change (bevy-comm-14, bevy-comm-15), and there's no llms.txt or first-party AI-consumption docs (bevy-probe-1, bevy-probe-rt-2). missing for 10: evidence of first-try success rate for LLM-generated Bevy code, stable API surface across versions, and first-party AI-friendly documentation.

   • [community] “Things have started to stabilize, but unless you're willing to get your hands dirty and deal with regular breaking changes, I don't yet reco…”
   • [community] “On the last update 0.10 -> 0.11, I had to make quite a few changes on my app, but this time it compiled out of the box!”
   • [community] “I'm put off by the limited docs. I've read the Bevy book, only takes a few minutes, and just like that I'm out of resources to turn to when …”
   • [community] “There's an unofficial complement to the docs... Unfortunately it's somewhat out of date... The effort to keep it up to date is somewhat low …”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”
   • [claimed-docs] “Examples that show how to use the various features of Bevy.”

   proof ↗⚑ flag

Copilot

1. ai-native userAn official AI assistant inside the engine helps with engine tasks — generating scripts, answering API questions, scaffolding scenes or assets

   weight 2 · round to Unity
   Unity~partialprobed6/10

   Unity has an official in-editor "Assistant" — docs confirm it exists and consumes Unity Credits for actions like generating images/models/messages (unity-docs-14), and runtime probes confirm Unity's AI tools (beta) including an MCP integration bundled in the com.unity.ai.assistant package (unity-probe-rt-1, unity-probe-4). However, the evidence pack lacks first-party documentation specifically describing script generation, API Q&A, or scene/asset scaffolding workflows for the assistant, and confirms it's still beta with closed distribution. Missing for 10: dedicated docs/examples showing the Assistant generating scripts or scaffolding scenes, independent hands-on reviews of assistant output quality.

   • [claimed-docs] “Whenever you generate an image, create a 3D model, produce a sound effect, or send a message to the Assistant, you spend Unity Credits from …”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [probe] “official MCP server documented at https://docs.unity3d.com/Packages/com.unity.ai.assistant@latest/index.html?subfolder=/manual/integration/u…”

   proof ↗⚑ flag

   Bevy—none0/10

   Bevy is a Rust game engine/library with no evidence of an official in-engine AI assistant; probes confirm no llms.txt, no official MCP, and only nascent third-party tooling (bevy_brp).

   • [probe] “PROBE llms.txt: HTTP 404 at https://bevy.org/llms.txt”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”

   proof ↗⚑ flag

Formats

1. technical artistStandard interchange formats — glTF, FBX, USD — import cleanly

   weight 2 · round drawn
   Unity—none0/10

   The evidence pack never mentions glTF, FBX, or USD import specifically — only generic Asset Database and packaging docs are cited, with no documentation or community proof of clean interchange-format import. Since format import is a fair and expected axis for a game engine's asset pipeline, absence of evidence means 'none' rather than 'na'.

   ⚑ flag

   Bevy—none0/10

   No evidence anywhere in the pack mentions glTF, FBX, USD, or any interchange-format import/asset-pipeline support; only glTF is a commonly known Bevy asset format but it's not cited here. Missing for 10: any docs or community mention of glTF/FBX/USD import, format fidelity, or asset-pipeline tooling.

   ⚑ flag

Import

1. technical artistAsset import is automatable — import hooks, presets, and pipeline scripts process incoming assets without hand-clicking each one

   weight 2 · round to Unity
   Unity~partialclaimed5/10

   Unity's docs confirm scripting APIs, editor extensibility, and an Asset Database that syncs source and imported assets, plus command-line automation for headless/batch operations—together implying pipeline scripting is possible, but no evidence specifically documents AssetPostprocessor import hooks or importer presets, the actual mechanism artists would use to automate imports. missing for 10: explicit documentation of AssetPostprocessor/import-hook API, importer preset system, and a hands-on example of a pipeline script processing incoming assets without manual clicks.

   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “The Asset Database stores information about the original source asset files and their imported counterparts to keep the two sets of data in …”
   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”

   proof ↗⚑ flag

   Bevy~partialcommunity3/10

   Bevy's Asset V2 system does support preprocessing and .meta files, which one community commenter calls 'super useful' for pipeline automation, but no first-party docs describe import hooks, presets, or scripting workflows for batch/automated asset processing. missing for 10: official documentation on asset import hooks/presets, evidence of scripted/batch pipeline tooling, and independent confirmation beyond a single community mention.

   • [community] “Bevy is one of my favorite game engines, especially for larger projects. Asset V2 preprocessing and .meta files look super useful.”

   proof ↗⚑ flag

Marketplace

1. game developerA large asset store or package ecosystem gives me ready-made models, tools, and plugins

   weight 2 · round to Unity
   Unity✓fullprobed9/10

   Unity's Package Manager and Asset Database provide a structured pipeline for packages/assets (unity-docs-12, unity-docs-13), and Unity operates a large public Asset Store ecosystem for third-party models, tools, and plugins, corroborated by community references to a massive Store with hundreds of assets (unity-comm-6) and thriving community add-ons like the 14k-star community MCP server (unity-probe-rt-1) showing ecosystem breadth. Missing for 10: no first-party evidence pack citation of Asset Store size/catalog numbers or independent reviews specifically praising asset variety.

   • [claimed-docs] “The Asset Database stores information about the original source asset files and their imported counterparts to keep the two sets of data in …”
   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”
   • [community] “Unity basically told us we were not welcome back to their Store, ever, even if we removed all LGPL code. Yet there are currently hundreds of…”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”

   proof ↗⚑ flag

   Bevy~partialcommunity5/10

   Bevy explicitly maintains an official third-party 'Assets' page listing community plugins, tools, and learning resources (bevy-docs-17), and community comments confirm an active ecosystem contributing new features and crates (bevy-comm-19). However, this is a curated links page rather than an integrated in-engine asset store, and the ecosystem is described as young/fragmented with docs gaps and frequent breaking changes affecting third-party plugin compatibility (bevy-comm-12, bevy-comm-15). Missing for 10: evidence of a large volume/maturity of ready-made models or marketplace-scale assets, integrated store UI, and quantified ecosystem size or quality assurance for third-party plugins.

   • [claimed-docs] “A collection of third-party Bevy assets, plugins, learning resources, and apps made by the community.”
   • [community] “Something delightful about this update: it has a lot of new features, some very early, but all by different authors. Seems like such a commu…”
   • [community] “Things have started to stabilize, but unless you're willing to get your hands dirty and deal with regular breaking changes, I don't yet reco…”
   • [community] “There's an unofficial complement to the docs... Unfortunately it's somewhat out of date... The effort to keep it up to date is somewhat low …”

   proof ↗⚑ flag

1. ai-native userPerform bulk operations across many items at once

   weight 2 · round to Unity
   Unity~partialclaimed4/10

   Unity's scripting API, AssetDatabase, and command-line/batch-mode automation (unity-docs-6/7/8/11/12) allow developers to write editor scripts that iterate over many assets or objects programmatically, which supports bulk operations, but there is no dedicated 'bulk operations' feature or AI-native tooling for it documented. Missing for 10: explicit bulk-edit/batch-apply feature, AI-agent-driven bulk workflows, and independent hands-on evidence of performing bulk operations at scale.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “The Asset Database stores information about the original source asset files and their imported counterparts to keep the two sets of data in …”

   proof ↗⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

2. ai-native userDefine rules that trigger actions automatically on events

   weight 3 · round to Unity
   Unity~partialclaimed4/10

   Unity's scripting API and editor extensibility let developers write custom event-driven code (e.g. callbacks, custom inspectors, command-line automation of build/launch workflows), which can be used to trigger actions on events, but the evidence never documents an actual declarative 'rules that trigger actions on events' system or AI-native automation trigger framework. Missing for 10: a documented rules/trigger engine (e.g. webhook-style or event-condition-action config), AI-specific automation hooks, and independent confirmation that non-scripted users can define such rules.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”

   proof ↗⚑ flag

   Bevy—none0/10

   The evidence pack describes Bevy's ECS, rendering, audio, and UI features but never mentions an event/trigger/rule system (e.g., Bevy Events, Observers, or ECS hooks) that would let a user define rules firing automatically on events. While such automation is plausible for a game engine's ECS, no evidence in the pack substantiates it.

   ⚑ flag

3. ai-native userVersion, review, and roll back my automations

   weight 1 · round drawn
   Unity—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

2d

1. game developer2D is a first-class workflow — sprites, tilemaps, 2D physics — not a 3D afterthought

   weight 2 · round to Bevy
   Unity~partialclaimed3/10

   Only unity-docs-1's tagline ('Build 2D and 3D games for any platform') references 2D at all; the rest of the evidence pack is dominated by 3D rendering, multiplayer, and platform-build docs with no mention of sprites, Tilemap, 2D physics, or 2D-specific tooling. Missing for 10: dedicated 2D sprite/animation docs, Tilemap system evidence, 2D physics engine documentation, and any community corroboration that 2D is treated as first-class rather than a side feature.

   • [claimed-docs] “Build 2D and 3D games for any platform”

   proof ↗⚑ flag

   Bevy~partialclaimed5/10

   Bevy's official docs explicitly list 2D rendering as a first-class feature alongside 3D (bevy-docs-2, bevy-docs-3), suggesting parity rather than a 3D-only focus, and community feedback confirms active engine use for real projects. However, there is no evidence in the pack of built-in tilemap support or first-party 2D physics (these are known to be third-party crates in the Bevy ecosystem), so the story's specific claims about tilemaps and 2D physics being first-class are unconfirmed. Missing for 10: evidence of native/first-party tilemap support, evidence of native/first-party 2D physics integration, and any community confirmation of 2D-specific workflow maturity.

   • [claimed-docs] “Render real-time 2D graphics for games and apps”
   • [claimed-docs] “A modern and flexible 3D renderer”
   • [claimed-docs] “Extensible: custom shaders, materials, and render pipelines”

   proof ↗⚑ flag

Performance

1. game developerProfile and scale — a real profiler, plus data-oriented paths (ECS, jobs, instancing) when scenes get heavy

   weight 2 · round to Bevy
   Unity—none0/10

   The evidence pack contains no mention of Unity's Profiler, ECS/DOTS, Job System, or GPU instancing — only generic claims about rendering/visuals, scripting APIs, and CLI/build tooling. Since this axis clearly applies to a game engine but no evidence in the pack substantiates the specific profiling or data-oriented tech stack, it must be scored as none. missing for 10: any mention of the Unity Profiler, ECS/DOTS, Job System, Burst compiler, or GPU instancing documentation/evidence.

   ⚑ flag

   Bevy~partialcommunity4/10

   Bevy's data-oriented ECS is well documented as the foundation for all engine/game logic (bevy-docs-1, bevy-docs-14, bevy-docs-20), and community accounts corroborate its data-driven, ECS-first workflow (bevy-comm-17). However, the evidence pack contains no mention of a built-in profiler/diagnostics tool, explicit job/parallel-system scheduling, or GPU instancing for heavy scenes — core parts of the story. Missing for 10: dedicated profiler tooling (e.g. tracing/diagnostics plugin), explicit job-system/parallelism documentation, and instancing support evidence.

   • [claimed-docs] “All engine and game logic uses Bevy ECS, a custom Entity Component System”
   • [claimed-docs] “Components: Rust structs that implement the Component trait”
   • [claimed-docs] “Unlike other Rust ECS implementations, which often require complex lifetimes, traits, builder patterns, or macros, Bevy ECS uses normal Rust…”
   • [community] “Pros: Very nice to work in Rust engine + Rust game. Once you get your brain thinking ECS it's tough to go back, feels very flexible. Very li…”

   proof ↗⚑ flag

Physics

1. game developerBuilt-in physics — rigid bodies, collisions, raycasts — works out of the box

   weight 2 · round drawn
   Unity—none0/10

   The evidence pack contains no documentation, community discussion, or probe results that specifically mention Unity's physics engine, rigid bodies, colliders, or raycasting — only generic references to building 2D/3D games, scripting APIs, and editor extensibility. Absence of evidence for this well-known capability must be scored as 'none' rather than inferred from outside knowledge.

   ⚑ flag

   Bevy—none0/10

   The evidence pack covers ECS, rendering, audio, UI, and scenes but contains no mention of physics, rigid bodies, collision detection, or raycasting capabilities. Built-in physics is a fair question for a game engine's core-engine axis, but nothing in the docs or community evidence shows Bevy ships this out of the box.

   ⚑ flag

Rendering

1. game developerThe engine ships a modern production 3D renderer — PBR materials, global illumination or baked lighting, shadows, post-processing

   weight 3 · round to Unity
   Unity~partialclaimed7/10

   Unity's docs confirm a modern rendering pipeline is offered ('scalable, captivating visuals using the latest advances in rendering, lighting, and visual effects') and marketing pages reference real-time 3D rendering/visual fidelity, consistent with Unity's known HDRP/URP pipelines supporting PBR, GI, shadows, and post-processing. However, the evidence pack is thin on specifics — no direct mention of PBR materials, baked/real-time GI systems, shadow techniques, or the post-processing stack by name. missing for 10: explicit documentation of PBR material workflow, GI/lightmapping details, shadow cascade features, post-processing stack/volume framework, and independent hands-on corroboration of rendering quality.

   • [claimed-docs] “Elevate your scenes with scalable, captivating visuals using the latest advances in rendering, lighting, and visual effects.”
   • [claimed-docs] “Build and review 3D projects in real time”
   • [claimed-docs] “Create and optimize high-end games and interactive experiences. Bring your team’s vision to life with Unity’s real-time development platform…”

   proof ↗⚑ flag

   Bevy~partialcommunity5/10

   Docs confirm a 'modern and flexible 3D renderer' with extensible custom shaders/materials/pipelines, and community hands-on feedback confirms shadows exist (though called 'jagged/low-res, reminds me of early Unity shadows'). However, the evidence pack never mentions global illumination, baked lighting, or a post-processing stack explicitly. Missing for 10: explicit documentation of GI/baked lighting support, explicit post-processing feature list, and independent corroboration of PBR material quality beyond the shadow-quality caveat.

   • [claimed-docs] “A modern and flexible 3D renderer”
   • [claimed-docs] “Extensible: custom shaders, materials, and render pipelines”
   • [community] “Not a criticism, but model projected shadows are very jagged or really low-res, reminds me of early Unity shadows.”

   proof ↗⚑ flag

Collaboration

1. studio leadThe project format and tooling play well with version control and multi-person teams — mergeable scenes, diffable text formats, or built-in collaboration

   weight 2 · round to Unity
   Unity~partialclaimed2/10

   Evidence only offers a vague marketing tagline ('Collaborate and iterate quickly with your team') with no detail on scene serialization format, diffability, merge tooling, or a named collaboration/VCS product; nothing describes mergeable scenes or text-based diff-friendly formats. Missing for 10: documentation of YAML/text scene serialization mode, a smart-merge tool for scenes/prefabs, and details of a built-in version-control/collaboration product (e.g. Unity VCS/Plastic) with independent corroboration.

   • [claimed-docs] “Collaborate and iterate quickly with your team”

   proof ↗⚑ flag

   Bevy—none0/10

   Evidence mentions a Scene system for saving/loading ECS worlds (bevy-docs-8) but nothing about its text format being diffable/mergeable, nor any built-in multi-user collaboration tooling. The 'code-first' workflow noted in bevy-probe-rt-2 is framed around agent-driven development, not team version-control workflows, so it doesn't substantiate this story.

   • [claimed-docs] “Create, save, and load ECS worlds using Bevy's Scene system”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”

   proof ↗⚑ flag

Editor

1. technical artistA full visual editor — viewport, inspector, prefabs/scene composition — is the primary way to build levels

   weight 3 · round to Unity
   Unity✓fullclaimed9/10

   Unity's Editor is explicitly documented as extendable with custom inspectors, editor windows, and property drawers, backed by scripting APIs and an Asset Database that underpins scene/prefab composition; this is Unity's well-known primary workflow (viewport, inspector, scene/prefab authoring). missing for 10: no direct hands-on/independent walkthrough of prefab workflows or viewport usage specifically, just docs on inspector/editor extension and asset management.

   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “The Asset Database stores information about the original source asset files and their imported counterparts to keep the two sets of data in …”
   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”

   proof ↗⚑ flag

   Bevy—none0/10

   Bevy's evidence describes a code-first Rust ECS engine (components, systems, scenes-as-data, hot reloading) but nothing about a visual editor with viewport, inspector, or prefab/scene composition UI; comment bevy-comm-8 even suggests users hope NOT to be forced into an in-engine editor, and probes show no official tooling filling this gap. Missing for full/partial credit: any first-party viewport/inspector GUI, prefab authoring workflow, or scene-composition editor.

   • [claimed-docs] “Create, save, and load ECS worlds using Bevy's Scene system”
   • [claimed-docs] “Get instant feedback on your changes without app restarts or recompiles”
   • [community] “The integrated code editor in Godot is actually something I don't like... I hope that Bevy users won't be forced to use the Bevy editor for …”

   proof ↗⚑ flag

Extensibility

1. game developerExtend and automate the editor itself — custom tools, editor scripts, plugins that manipulate scenes and assets programmatically

   weight 3 · round to Unity
   Unity✓fullclaimed9/10

   Unity's docs explicitly document extending the editor with custom inspectors, Editor Windows, Property Drawers, and direct scripting access to public Unity APIs, plus AssetDatabase APIs for programmatic asset manipulation and a Package Manager for distributing/consuming editor tooling — directly matching the story's ask for custom tools/editor scripts/plugins that manipulate scenes and assets. This is a first-party, mature, widely-used capability (also evidenced by a large third-party ecosystem like community MCP tooling built on this extensibility). Missing for 10: independent hands-on developer testimonials specifically about editor scripting workflows (community evidence in the pack focuses on pricing/licensing controversies, not editor extensibility).

   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [claimed-docs] “The Asset Database stores information about the original source asset files and their imported counterparts to keep the two sets of data in …”
   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”

   proof ↗⚑ flag

   Bevy—none0/10

   Bevy's evidence shows only a code-first workflow (ECS, scenes, plugins) and mentions no official editor application to extend; the closest hint is a third-party 'bevy_brp' remote-protocol tool with just 70 stars, not first-party editor scripting/plugin support for manipulating scenes and assets. missing for 10: any first-party editor product, documented editor scripting/plugin API, or mature ecosystem tooling for automating scene/asset manipulation via an editor UI.

   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”
   • [claimed-docs] “Create, save, and load ECS worlds using Bevy's Scene system”

   proof ↗⚑ flag

Ci

1. game developerBuild and export the project from the command line, headless, in CI — no human clicking an editor

   weight 3 · round to Unity
   Unity✓fullprobed8/10

   Unity officially documents command-line/editor CLI args, headless mode (-batchmode/-nographics), and BuildSettings/build profiles for automated builds, which together enable scripted, non-interactive CI builds; Unity Hub can be installed headlessly via package managers. Missing for 10: no independent hands-on CI pipeline report confirming end-to-end success, and community evidence notes real friction with setting up CI/build servers due to licensing costs.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “Unity can build your application for different platforms with unique build configurations using build profiles in the Unity Editor.”
   • [probe] “official CLI documented at https://docs.unity3d.com/Manual/EditorCommandLineArguments.html”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity Hub installs keylessly from Homebrew (cask unity-hub 3.21.2, 'Management tool for Unity') — the e…”
   • [community] “The extravagant cost of a Unity seat meant we couldn't afford to give anyone except the Unity devs a license... For the same reason, we coul…”

   proof ↗⚑ flag

   Bevy~partialprobed5/10

   Bevy is a code-first Rust library built and run via cargo, with no mandatory editor (bevy-docs-21, bevy-comm-8, bevy-probe-rt-2), which inherently supports command-line/CI builds. However, there is no explicit documentation of a headless mode flag, export pipeline, or CI-specific tooling/examples, and no official CI templates or GitHub Actions references are present in the evidence pack. missing for 10: explicit headless-mode/export documentation, CI pipeline examples or templates, and confirmation of asset-building/export automation without a GUI step.

   • [claimed-docs] “Bevy is just a normal Rust dependency. You can either add it to an existing Rust project or create a new one.”
   • [community] “The integrated code editor in Godot is actually something I don't like... I hope that Bevy users won't be forced to use the Bevy editor for …”
   • [probe] “PROBE runtime negative (recorded 2026-09-15): bevy.org serves no llms.txt (HTTP 404; docs.rs likewise) and no official MCP exists — communit…”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

Server

1. game developerGame logic runs headless on servers — a dedicated-server or server-runtime build without rendering

   weight 2 · round to Unity
   Unity✓fullprobed8/10

   Unity's Player command-line docs explicitly describe running the application in headless mode with no rendering or input, and this combines with documented command-line/batchmode automation for server builds; Unity is widely used to build dedicated-server binaries via this mechanism. Missing for 10: no first-party 'dedicated server build target' walkthrough or independent case study confirming headless server deployment at scale.

   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [probe] “official CLI documented at https://docs.unity3d.com/Manual/EditorCommandLineArguments.html”

   proof ↗⚑ flag

   Bevy—none0/10

   The evidence pack covers Bevy's ECS, rendering, UI, audio, and platform support, but contains no mention of a headless/dedicated-server build mode, disabling rendering plugins, or server-runtime configuration. Since this is a plausible and common need for a game engine, absence of evidence means the axis is unmet rather than inapplicable.

   ⚑ flag

Testing

1. game developerTests run headlessly — unit and integration tests of game code execute in CI against the real engine

   weight 2 · round to Unity
   Unity~partialcommunity5/10

   Unity docs confirm the Editor/Player can be run headlessly via command-line arguments (-batchmode, -nographics equivalents) which is the foundation for CI automation (unity-docs-6,7,8), and community evidence confirms a CI build server setup is a real (if costly) practice (unity-comm-13). However, there is no direct evidence of Unity's Test Runner/Test Framework CLI flags (e.g., -runTests) or of CI-based unit/integration test execution against the real engine — the pack only shows generic headless launch capability, not test-specific automation. missing for 10: explicit Unity Test Framework / -runTests CLI documentation, evidence of CI pipelines executing engine unit tests, independent hands-on confirmation of headless test runs succeeding.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [community] “The extravagant cost of a Unity seat meant we couldn't afford to give anyone except the Unity devs a license... For the same reason, we coul…”

   proof ↗⚑ flag

   Bevy—none0/10

   The evidence pack contains no mention of headless mode, CI test execution, integration testing, or automated test frameworks for Bevy game logic — nothing about running engine/game tests without a display or in continuous integration.

   ⚑ flag

Governance

1. studio leadThe project's governance and funding are transparent — a foundation, published finances, or a public roadmap I can plan against

   weight 1 · round drawn
   Unity—none0/10

   Unity is a commercial, for-profit company with no evidence of foundation governance, published financials, or a public roadmap a studio could plan against; the only related material is marketing pages and a blog post reversing a pricing decision. Community evidence instead documents unilateral, retroactive policy changes (comm-2, comm-7, comm-12, comm-15) that undermine any sense of predictable governance.

   • [claimed-docs] “Unity is Canceling the Runtime Fee”
   • [community] “It reminds me of Darth Vader's line: 'I have altered the deal. Pray I don't alter it further.' The per-install fee applies retroactively to …”
   • [community] “Unity's mishandling of the Runtime Fee policy announcement has caused permanent damage to their reputation. I follow a lot of game developer…”
   • [community] “Unity forced my last company into the more expensive license unilaterally and with no discussion. They doubled our costs just because they c…”
   • [community] “This shows once again that Unity is an unreliable option for new projects. The worst part is not the 4% fee, but the bluntness with which Un…”

   proof ↗⚑ flag

   Bevy—none0/10

   Evidence documents Bevy's open-source MIT/Apache-2.0 licensing and community activity, but nothing about a governing foundation, published finances, or an official public roadmap a studio could plan against — only migration guides for past releases are mentioned. missing for 10: evidence of a foundation or legal entity, published budget/financials, and a forward-looking public roadmap.

   • [claimed-docs] “It is free and open-source forever under your choice of the MIT or Apache 2.0 licenses.”
   • [claimed-docs] “100% free. Forever and always * Open Source under the permissive MIT or Apache 2.0 licenses * No contracts * No license fees * No sa…”
   • [claimed-docs] “Every Bevy update brings new functionality and improvements. Follow these guides to migrate your project to the latest Bevy has to offer!”
   • [community] “Something delightful about this update: it has a lot of new features, some very early, but all by different authors. Seems like such a commu…”

   proof ↗⚑ flag

License

1. studio leadThe license is permissive with no royalties or per-install fees — I keep what my game earns

   weight 3 · round to Bevy
   Unity!disputedcontradicted3/10

   Unity's default model is seat/subscription-based (not per-revenue royalties) and the controversial per-install Runtime Fee was announced and then canceled (unity-docs-21), which superficially supports 'no royalties/per-install fees.' However, concrete community evidence directly contradicts the 'permissive, keep what you earn' framing: the per-install fee was retroactively applied to already-shipped games before cancellation (unity-comm-2), studios report being unilaterally forced into pricier license tiers (unity-comm-12), and developers describe Unity's terms as able to 'change at any moment' (unity-comm-15) — the opposite of a stable, low-friction license. missing for 10: vendor documentation of the actual current licensing terms/royalty structure, resolution confirming no future fee reintroduction, and independent legal/financial analysis of the license's permissiveness.

   • [claimed-docs] “Unity is Canceling the Runtime Fee”
   • [community] “It reminds me of Darth Vader's line: 'I have altered the deal. Pray I don't alter it further.' The per-install fee applies retroactively to …”
   • [community] “Unity forced my last company into the more expensive license unilaterally and with no discussion. They doubled our costs just because they c…”
   • [community] “This shows once again that Unity is an unreliable option for new projects. The worst part is not the 4% fee, but the bluntness with which Un…”
   • [community] “Unity's mishandling of the Runtime Fee policy announcement has caused permanent damage to their reputation. I follow a lot of game developer…”

   proof ↗⚑ flag

   Bevy✓fullprobed9/10

   Bevy's own site explicitly states it is 100% free forever, MIT OR Apache-2.0 licensed, with no contracts, no license fees, and no sales cuts, directly satisfying the studio-lead's ask of no royalties or per-install fees. This is corroborated independently by crates.io license metadata and by community commentary praising the permissive MIT licensing as 'no strings attached.' Missing for 10: no explicit legal/contract analysis or enterprise-scale case study confirming zero royalty obligations at large studio scale.

   • [claimed-docs] “100% free. Forever and always * Open Source under the permissive MIT or Apache 2.0 licenses * No contracts * No license fees * No sa…”
   • [claimed-docs] “It is free and open-source forever under your choice of the MIT or Apache 2.0 licenses.”
   • [community] “MIT License, well done! It's so refreshing to see things released with no strings attached... a breathe of fresh air as a potential end user…”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

Source

1. game developerRead and modify the full engine source when I hit a wall

   weight 2 · round to Bevy
   Unity—none0/10

   Evidence covers scripting APIs, editor extensibility, and packages, but nothing indicates access to or modification of Unity's actual engine source code (Unity is closed-source/proprietary); community evidence instead highlights licensing rigidity and forced fee changes, reinforcing lack of source openness. Missing for 10: any documentation of source code licenses, C++ engine source access program, or ability to recompile/modify the core engine.

   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [community] “Unity forced my last company into the more expensive license unilaterally and with no discussion. They doubled our costs just because they c…”
   • [community] “The extravagant cost of a Unity seat meant we couldn't afford to give anyone except the Unity devs a license... For the same reason, we coul…”

   proof ↗⚑ flag

   Bevy✓fullprobed9/10

   Bevy is fully open-source (MIT/Apache 2.0), with source hosted openly, allowing developers to read and modify the engine itself; community confirms code is clean/readable and license is unrestricted ('no strings attached'). Missing for 10: no explicit hands-on account of a developer patching/forking the engine source to unblock themselves, only license and code-quality corroboration.

   • [claimed-docs] “It is free and open-source forever under your choice of the MIT or Apache 2.0 licenses.”
   • [claimed-docs] “100% free. Forever and always * Open Source under the permissive MIT or Apache 2.0 licenses * No contracts * No license fees * No sa…”
   • [claimed-docs] “Why are we continuing to build up the ecosystems of closed-source monopolies that take cuts of our sales and deny us visibility into the tec…”
   • [community] “Got the chance of running the examples and glance over the code... it looks incredibly elegant and clean. Almost feels like this could make …”
   • [community] “MIT License, well done! It's so refreshing to see things released with no strings attached... a breathe of fresh air as a potential end user…”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

Trust

1. studio leadThe pricing and license terms have a track record of stability — no retroactive changes that reprice games already shipped

   weight 2 · round to Bevy
   Unity—none0/10

   Community evidence directly documents a retroactive pricing change (the 2023 Runtime Fee applied to already-shipped games) and multiple accounts of unilateral license/cost changes forced on existing customers, the opposite of the stability this story asks for; no vendor commitment to non-retroactive pricing is evidenced.

   • [community] “It reminds me of Darth Vader's line: 'I have altered the deal. Pray I don't alter it further.' The per-install fee applies retroactively to …”
   • [community] “Unity forced my last company into the more expensive license unilaterally and with no discussion. They doubled our costs just because they c…”
   • [community] “This shows once again that Unity is an unreliable option for new projects. The worst part is not the 4% fee, but the bluntness with which Un…”
   • [claimed-docs] “Unity is Canceling the Runtime Fee”

   proof ↗⚑ flag

   Bevy✓fullcommunity7/10

   Bevy is licensed under MIT/Apache 2.0 with explicit 'no contracts, no license fees, no sales cuts, forever' commitments, and these are irrevocable open-source licenses that cannot retroactively reprice already-shipped games — corroborated by community praise for the license having 'no strings attached.' Missing for 10: a long multi-year track record (Bevy is a young, pre-1.0 project) and any explicit governance statement committing to never relicense future versions restrictively.

   • [claimed-docs] “100% free. Forever and always * Open Source under the permissive MIT or Apache 2.0 licenses * No contracts * No license fees * No sa…”
   • [claimed-docs] “It is free and open-source forever under your choice of the MIT or Apache 2.0 licenses.”
   • [community] “MIT License, well done! It's so refreshing to see things released with no strings attached... a breathe of fresh air as a potential end user…”

   proof ↗⚑ flag

1. ai-native userDo everything through the API that I can do in the UI

   weight 2 · round to Unity
   Unity~partialprobed5/10

   Unity exposes extensive scripting APIs, editor extensibility, and CLI/command-line automation for builds and headless runs, letting many UI workflows be scripted, but there is no general REST/GraphQL API mirroring the full Editor UI — automation is Editor/CLI/C#-script based rather than a universal API surface, and no OpenAPI spec exists (404s confirmed). missing for 10: a documented general-purpose API (not just CLI args/C# scripting) covering all UI actions, evidence of parity between UI and programmatic access, and confirmation openapi/swagger specs exist.

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “Unity lets you extend the editor with your own custom inspectors and Editor Windows and you can define how properties are displayed in the i…”
   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [probe] “PROBE openapi: all candidate paths 404 (https://docs.unity3d.com/openapi.json, https://docs.unity3d.com/swagger.json, https://docs.unity3d.c…”
   • [probe] “official CLI documented at https://docs.unity3d.com/Manual/EditorCommandLineArguments.html”

   proof ↗⚑ flag

   Bevy—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

2. ai-native userExport all of my data in open formats and leave

   weight 3 · round to Bevy
   Unity—none0/10

   The evidence pack contains no documentation of a data-export feature or open-format portability guarantee for Unity projects (assets, scenes, or AI credits data); most content is about platform support, editor extensibility, and pricing controversies, not data portability.

   ⚑ flag

   Bevy~partialprobed5/10

   Bevy is a local, open-source Rust engine (MIT/Apache-2.0) with no cloud data lock-in, and its Scene system lets you save/load ECS worlds in the open RON format, which aligns with the openness theme. However there's no explicit documentation or tooling framed around 'exporting all your data and leaving' (e.g., data migration guides, guaranteed format stability) since Bevy isn't a hosted service holding user data in the first place. Missing for 10: explicit data-export/migration documentation, guarantees around long-term format stability given breaking API changes each release, and any first-party statement on data portability beyond the general OSS license.

   • [claimed-docs] “Create, save, and load ECS worlds using Bevy's Scene system”
   • [claimed-docs] “It is free and open-source forever under your choice of the MIT or Apache 2.0 licenses.”
   • [claimed-docs] “100% free. Forever and always * Open Source under the permissive MIT or Apache 2.0 licenses * No contracts * No license fees * No sa…”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

3. ai-native userRead the product's source under an open license

   weight 2 · round to Bevy
   Unity—none0/10

   Unity Engine is proprietary; there is no evidence of an open-source license for its source code, and Unity is a closed commercial product per the evidence (Package Manager, paid plans, closed MCP distribution). This is a fair axis to ask of any dev platform, but no evidence supports open-source availability of Unity's source.

   • [claimed-docs] “Packages deliver a wide range of enhancements to Unity through the Package Manager.”
   • [claimed-docs] “Unity’s free plan, Unity Personal, is for individuals and small organizations with less than $100K of revenue and funds raised in the last 1…”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”

   proof ↗⚑ flag

   Bevy✓fullprobed9/10

   Bevy's source and docs are explicitly MIT OR Apache-2.0 licensed, confirmed both by first-party docs and independent runtime crates.io metadata, and community commenters corroborate the open, permissive licensing and code readability. Missing for 10: no direct GitHub repo citation in the evidence pack, though license and source availability are otherwise well-documented.

   • [claimed-docs] “It is free and open-source forever under your choice of the MIT or Apache 2.0 licenses.”
   • [claimed-docs] “100% free. Forever and always * Open Source under the permissive MIT or Apache 2.0 licenses * No contracts * No license fees * No sa…”
   • [community] “MIT License, well done! It's so refreshing to see things released with no strings attached... a breathe of fresh air as a potential end user…”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

4. ai-native userSelf-host the core product

   weight 3 · round to Bevy
   Unity~partialprobed6/10

   Unity's core Editor/Player is inherently installed and run on the user's own machines (Unity Hub installs locally, headless -batchmode/-nographics CLI for CI build servers, EditorCommandLineArguments for automation), so the core engine is effectively self-hosted by design rather than a vendor-controlled cloud service. However, Unity's newer AI-native features (Unity AI Assistant, MCP integration) are explicitly cloud-metered via Unity Credits with no public/self-hostable package, so the AI-native layer itself cannot be self-hosted. Missing for 10: a documented self-hosted deployment path for the AI/MCP layer, and any first-party guidance on self-hosting build infrastructure at scale (e.g. license/build-server constraints noted in community reports).

   • [claimed-docs] “You can run the Unity Editor and Players from command-line interfaces to change and customize how they run at launch time.”
   • [claimed-docs] “You can launch the Unity Editor and Player with additional command line arguments to control startup behavior, configure settings, or automa…”
   • [claimed-docs] “Run the application in headless mode. In this mode, the application doesn’t display anything or accept user input.”
   • [claimed-docs] “Unity can build your application for different platforms with unique build configurations using build profiles in the Unity Editor.”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity ships an OFFICIAL MCP server as part of Unity's AI tools (beta) inside the com.unity.ai.assistant…”
   • [probe] “PROBE runtime (recorded 2026-09-15): Unity Hub installs keylessly from Homebrew (cask unity-hub 3.21.2, 'Management tool for Unity') — the e…”
   • [community] “The extravagant cost of a Unity seat meant we couldn't afford to give anyone except the Unity devs a license... For the same reason, we coul…”

   proof ↗⚑ flag

   Bevy✓fullcommunity7/10

   Bevy is not a hosted service at all — it's an open-source (MIT/Apache-2.0) Rust library added directly as a dependency to your own project and compiled/run entirely on your own machine, satisfying self-hosting by default with no server or cloud dependency (bevy-docs-18, bevy-docs-21, bevy-docs-25). Community corroboration confirms the open license and local dev workflow (bevy-comm-2). missing for 10: explicit vendor-authored self-hosting/deployment guidance (e.g., docs discussing running Bevy apps as self-hosted servers or headless builds) and independent verification of self-hosted production deployments.

   • [claimed-docs] “It is free and open-source forever under your choice of the MIT or Apache 2.0 licenses.”
   • [claimed-docs] “Bevy is just a normal Rust dependency. You can either add it to an existing Rust project or create a new one.”
   • [claimed-docs] “100% free. Forever and always * Open Source under the permissive MIT or Apache 2.0 licenses * No contracts * No license fees * No sa…”
   • [community] “MIT License, well done! It's so refreshing to see things released with no strings attached... a breathe of fresh air as a potential end user…”

   proof ↗⚑ flag

Targets

1. studio leadOne project exports to desktop, mobile, and (directly or via partners) consoles

   weight 3 · round to Unity
   Unity✓fullclaimed8/10

   Unity's docs explicitly advertise building for 25+ platforms including desktop, mobile, and consoles via build profiles/Build Settings, and it is well established that console export happens through Unity's console-partner program rather than open SDKs. Missing for 10: no direct evidence pack detail on console-specific partner workflow/certification process or independent studio confirmation of simultaneous multi-platform shipping.

   • [claimed-docs] “Build 2D and 3D games for any platform”
   • [claimed-docs] “Discover 25+ platforms Unity supports”
   • [claimed-docs] “Unity can build your application for different platforms with unique build configurations using build profiles in the Unity Editor.”
   • [claimed-docs] “Ship big games with small teams”

   proof ↗⚑ flag

   Bevy~partialcommunity5/10

   Docs confirm one Bevy project can target desktop (Windows/macOS/Linux), mobile (iOS/Android) and Web via a single codebase [bevy-docs-6], and community feedback corroborates real-world mobile/web use [bevy-comm-10][bevy-comm-20]. However, there is no evidence—first-party or community—of console export capability, whether direct or via third-party porting partners, which is a key part of the story. Missing for 10: any mention of console targets (Switch/PlayStation/Xbox), official or partner-based console export tooling, or case studies of console shipping.

   • [claimed-docs] “Support for all major platforms: Windows, MacOS, Linux, Web, iOS, Android”
   • [community] “We support low-end devices well! Bevy runs well on iOS currently... Fans spinning is a known issue, but it is generally decoupled from frame…”
   • [community] “Man, you guys really kill it with blog/changelog announcements. Great job! For my use case, Bevy web (and mobile is nice too) support would …”

   proof ↗⚑ flag

Web

1. web developerMy game runs in the browser with a reasonable payload — WebGL today, and a credible WebGPU story

   weight 2 · round to Bevy
   Unity—none0/10

   The evidence pack only offers generic cross-platform claims (e.g., '25+ platforms', 'any platform') with no mention of WebGL, WebGPU, browser payload size, or any web-specific export tooling; nothing addresses this story's specific subject.

   ⚑ flag

   Bevy~partialcommunity5/10

   Bevy documents official Web platform support and showcases live wasm-compiled examples running in-browser, and a community comment shows real interest in adopting Bevy specifically for web/mobile targets. However, the evidence never mentions WebGPU explicitly, payload size/optimization guidance, or any hands-on report of browser performance/bundle size — the WebGPU 'credible story' half of the claim is unevidenced. Missing for 10: explicit WebGPU backend documentation or roadmap, payload-size/optimization guidance, and independent hands-on confirmation of web build performance.

   • [claimed-docs] “Support for all major platforms: Windows, MacOS, Linux, Web, iOS, Android”
   • [claimed-docs] “Browse bevy examples compiled to wasm and running directly in your browser!”
   • [community] “Man, you guys really kill it with blog/changelog announcements. Great job! For my use case, Bevy web (and mobile is nice too) support would …”

   proof ↗⚑ flag

2. web developerThe engine installs from a package registry into my existing toolchain — a library I import, bundle, and tree-shake like any dependency

   weight 2 · round drawn
   Unity—none0/10

   The axis applies to this product kind (peer products hold positive or none verdicts on this story), so lack of evidence for an applicable capability is "none", never "na". (na/none harmonized at arena bring-up — see pipeline/scripts/na-harmonize.ts.)

   ⚑ flag

   Bevy—none0/10

   Bevy is distributed exclusively as a Rust crate via crates.io/cargo (bevy-docs-21, bevy-probe-rt-1), not as an npm/JS package; its 'Web' platform support (bevy-docs-6) means compiling to WASM as a game binary, not shipping a tree-shakeable JS library a web developer imports and bundles. No evidence shows npm registry presence, ES-module packaging, or tree-shaking support.

   • [claimed-docs] “Bevy is just a normal Rust dependency. You can either add it to an existing Rust project or create a new one.”
   • [claimed-docs] “Support for all major platforms: Windows, MacOS, Linux, Web, iOS, Android”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

Iteration

1. game developerThe edit-run loop is fast — hot reload or near-instant preview after a script change

   weight 2 · round to Bevy
   Unity—none0/10

   The evidence pack covers scripting APIs, editor extensibility, CLI/build automation, and packages, but contains no documentation or community evidence specifically about hot reload, domain reload speed, or near-instant preview after script changes — a well-known pain point/feature area for Unity that simply isn't addressed here.

   ⚑ flag

   Bevy~partialprobed5/10

   Bevy's own docs directly claim 'instant feedback on your changes without app restarts or recompiles' and cite very fast compile times (0.8–3.0s) with a 'fast compiles' config, which matches the story's intent. However, Bevy is a Rust-native engine (not script-based), so this reload speed is achieved via build tooling/dynamic linking rather than a true scripting hot-reload workflow, and there is no independent/hands-on community confirmation of this specific edit-run loop experience — community comments focus on ECS ergonomics, docs quality, and breaking changes instead. Missing for 10: independent/hands-on verification of the hot-reload claim, clarity on scripting vs. Rust recompilation semantics, and community testimony specifically about iteration speed.

   • [claimed-docs] “Get instant feedback on your changes without app restarts or recompiles”
   • [claimed-docs] “With Bevy you can expect 0.8-3.0 seconds with the "fast compiles" configuration”
   • [probe] “PROBE runtime (recorded 2026-09-15): bevy resolves on crates.io — `cargo search bevy` → 'bevy = "0.19.1" # A refreshingly simple data-driven…”

   proof ↗⚑ flag

Language

1. game developerThe primary scripting language is productive and fully exposes the engine API, with a debugger behind it

   weight 3 · round to Bevy
   Unity~partialcommunity4/10

   Evidence confirms Unity exposes public scripting APIs directly for fine-grained control and customization (unity-docs-11), and community comments corroborate that C# scripting is product993 and lets devs 'ignore the engine features' (unity-comm-4), supporting productivity. However, there is no evidence in the pack about a debugger being available or integrated for the scripting language, nor any detail on API completeness/coverage. Missing for 10: documentation or corroboration of a debugger (breakpoints, step-through, attach-to-process) for the scripting workflow, and evidence of full API surface coverage beyond general scripting docs.

   • [claimed-docs] “Interacting directly with the public Unity APIs allows for finer control and a greater degree of customization.”
   • [community] “I used XNA, then MS killed it... then switched to Unity, been using it since 2012... As a lone indie dev I find Unreal very tedious and slow…”

   proof ↗⚑ flag

   Bevy~partialcommunity5/10

   Bevy uses plain Rust as its 'scripting' layer, and docs plus community comments confirm the ECS API is idiomatic, fully native Rust with no macros/lifetimes needed (bevy-docs-14, bevy-docs-20, bevy-comm-3, bevy-comm-4), which is a strong productivity/API-exposure signal. However, there is no evidence at all of a dedicated debugger or debugging workflow behind this scripting layer, and community feedback flags limited/out-of-date docs and frequent breaking changes as productivity friction (bevy-comm-14, bevy-comm-15, bevy-comm-12). Missing for 10: explicit debugger/debugging-tool evidence, confirmation of full API surface coverage beyond ECS basics, and independent hands-on accounts of debugging Bevy games.

   • [claimed-docs] “Components: Rust structs that implement the Component trait”
   • [claimed-docs] “Unlike other Rust ECS implementations, which often require complex lifetimes, traits, builder patterns, or macros, Bevy ECS uses normal Rust…”
   • [community] “I have to say the API seems to be very pleasant and simple at a glance. Kudos to the author! This pattern is a great example of how Rust ach…”
   • [community] “This is amazing. Seriously: I had a look at nearly every game engine/GUI solution in Rust and this is by far the most thought out, ergonomic…”
   • [community] “I'm put off by the limited docs. I've read the Bevy book, only takes a few minutes, and just like that I'm out of resources to turn to when …”
   • [community] “There's an unofficial complement to the docs... Unfortunately it's somewhat out of date... The effort to keep it up to date is somewhat low …”
   • [community] “Things have started to stabilize, but unless you're willing to get your hands dirty and deal with regular breaking changes, I don't yet reco…”

   proof ↗⚑ flag

Visual

1. technical artistBuild gameplay logic with visual scripting without writing code

   weight 2 · round drawn
   Unity—none0/10

   The evidence pack contains no mention of Unity's Visual Scripting tool (or any no-code/node-based logic system) — it only documents C# scripting, editor extension APIs, and command-line tooling. Missing for 10: any documentation of a visual/node-based scripting system, tutorials or community proof of technical artists building gameplay logic without code.

   ⚑ flag

   Bevy—none0/10

   Bevy is explicitly a code-first, Rust-based ECS engine (bevy-docs-1, bevy-docs-14, bevy-docs-20, bevy-docs-21) with no mention of a visual scripting system or node-based logic editor anywhere in the evidence; community feedback even discusses concerns about being forced into a code editor, reinforcing the code-only workflow.

   • [claimed-docs] “All engine and game logic uses Bevy ECS, a custom Entity Component System”
   • [claimed-docs] “Components: Rust structs that implement the Component trait”
   • [claimed-docs] “Unlike other Rust ECS implementations, which often require complex lifetimes, traits, builder patterns, or macros, Bevy ECS uses normal Rust…”
   • [claimed-docs] “Bevy is just a normal Rust dependency. You can either add it to an existing Rust project or create a new one.”
   • [community] “The integrated code editor in Godot is actually something I don't like... I hope that Bevy users won't be forced to use the Bevy editor for …”

   proof ↗⚑ flag