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How Zero’s scores are calculated

The full audit trail, recomputed from the verdict data at build time through the same code that produced the leaderboard: verdict × quality × story weight per cell, cells sum to dimension scores, dimensions blend into the PA Score. Every number on the product page is reproducible from this page alone; for why the formula looks like this, see the methodology.

verdict factors: full ×1.0 · partial ×0.6 · disputed ×0.3 · none ×0.0 · n/a excluded from both sides · cell points = weight × quality × factor · cell max = weight × 10

PA Score28/100

Agent-ready 29.1 × 0.30 = 8.73

API quality 0.0 × 0.20 = 0.00

Openness 47.2 × 0.20 = 9.44

Built-in AI 57.8 × 0.15 = 8.67

Automation 8.6 × 0.15 = 1.29

(8.73 + 0.00 + 9.44 + 8.67 + 1.29) ÷ (0.30 + 0.20 + 0.20 + 0.15 + 0.15) = 28.13 ÷ 1.00 = 28.1

Scores are stored to 1 decimal; the product page’s pills round to whole numbers for display. Each dimension below shows the stories, verdicts, and cited evidence behind its number.

Agent-ready29.1/100×0.30 of the PA blend

Outside-in: can YOUR agent reach and drive this product — API, MCP, CLI, headless runs, agent docs.

Point an agent at llms.txt or agent-oriented docsweight 2

2 (weight) × 6 (quality) × 0.6 (partial) = 7.2 of 20 max

  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”
  • [probe] https://github.com/Mail-0/Zero/blob/staging/MCP.md“official MCP server documented at https://github.com/Mail-0/Zero/blob/staging/MCP.md”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“You can connecto ZeroMCP using two methods: 1. Better Auth session token 2. OAuth (Coming soon)”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”

Run the product headlessly / in CI for automationweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Plug MCP servers into this product so it can use their toolsweight 3

3 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 30 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“You can connecto ZeroMCP using two methods: 1. Better Auth session token 2. OAuth (Coming soon)”
  • [probe] https://github.com/Mail-0/Zero/blob/staging/MCP.md“official MCP server documented at https://github.com/Mail-0/Zero/blob/staging/MCP.md”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”

Connect an agent via an official MCP serverweight 3

3 (weight) × 8 (quality) × 1.0 (full) = 24.0 of 30 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“You can connecto ZeroMCP using two methods: 1. Better Auth session token 2. OAuth (Coming soon)”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Get email threads by ID - List emails in specific folders - Create and send new emails - Create email drafts - Send existing drafts - Delete emails”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”
  • [probe] https://github.com/Mail-0/Zero/blob/staging/MCP.md“official MCP server documented at https://github.com/Mail-0/Zero/blob/staging/MCP.md”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Use an official CLIweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“You can connecto ZeroMCP using two methods: 1. Better Auth session token 2. OAuth (Coming soon)”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/.github/CONTRIBUTING.md“View and edit data with Drizzle Studio pnpm db:studio”
  • [probe] https://github.com/Mail-0/Zero/blob/staging/MCP.md“official MCP server documented at https://github.com/Mail-0/Zero/blob/staging/MCP.md”

Drive the product through a documented public APIweight 3

3 (weight) × 8 (quality) × 1.0 (full) = 24.0 of 30 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“You can connecto ZeroMCP using two methods: 1. Better Auth session token 2. OAuth (Coming soon)”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Get email threads by ID - List emails in specific folders - Create and send new emails - Create email drafts - Send existing drafts - Delete emails”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”
  • [probe] https://github.com/Mail-0/Zero/blob/staging/MCP.md“official MCP server documented at https://github.com/Mail-0/Zero/blob/staging/MCP.md”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Issue scoped/least-privilege API credentials for an agentweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“You can connecto ZeroMCP using two methods: 1. Better Auth session token 2. OAuth (Coming soon)”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Build against official SDKsweight 2

2 (weight) × 5 (quality) × 0.6 (partial) = 6.0 of 20 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Modify email labels”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“You can connecto ZeroMCP using two methods: 1. Better Auth session token 2. OAuth (Coming soon)”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Get email threads by ID - List emails in specific folders - Create and send new emails - Create email drafts - Send existing drafts - Delete emails”
  • [probe] https://github.com/Mail-0/Zero/blob/staging/MCP.md“official MCP server documented at https://github.com/Mail-0/Zero/blob/staging/MCP.md”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”
  • [github] https://github.com/Mail-0/Zero“🚀 Developer-Friendly – Built with extensibility and integrations in mind.”

Subscribe to events via webhooksweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Agent-ready = 61.2 ÷ 210 × 100 = 29.1

API quality0.0/100×0.20 of the PA blend

The programmable surface once an agent is there — machine-readable spec, interactive docs, sandbox, versioning discipline.

Explore an interactive API reference with runnable examplesweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Download a machine-readable API spec (OpenAPI or equivalent)weight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Test against a sandbox environment without touching production dataweight 1

1 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 10 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Rely on versioned APIs with a documented deprecation policyweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

API quality = 0.0 ÷ 70 × 100 = 0.0

Openness47.2/100×0.20 of the PA blend

Can you leave, inspect, or self-host — data export, open source, portability.

Do everything through the API that I can do in the UIweight 2

2 (weight) × 6 (quality) × 0.6 (partial) = 7.2 of 20 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Search emails with custom queries - Filter emails by labels”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about mailbox content - Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Get email threads by ID - List emails in specific folders - Create and send new emails - Create email drafts - Send existing drafts - Delete emails”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Get all user labels - Create new custom labels with custom colors - Delete existing labels”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/ROADMAP.md“Customizable keyboard shortcuts”
  • [github] https://github.com/Mail-0/Zero“Customizable UI & Features – Tailor your email experience the way you want it.”

Export all of my data in open formats and leaveweight 3

3 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 30 max

  • [github] https://github.com/Mail-0/Zero“gives users the power to **self-host** their own email app”
  • [github] https://github.com/Mail-0/Zero“gives users the power to self-host their own email app while also integrating external services like Gmail and other email providers”
  • [github] https://github.com/Mail-0/Zero“Zero does not track, collect, or sell your data in any way.”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/.github/CONTRIBUTING.md“View and edit data with Drizzle Studio pnpm db:studio”

Read the product's source under an open licenseweight 2

2 (weight) × 8 (quality) × 1.0 (full) = 16.0 of 20 max

  • [github] https://github.com/Mail-0/Zero“Self-Hosting Freedom – Run your own email app with ease.”
  • [github] https://github.com/Mail-0/Zero“gives users the power to **self-host** their own email app”
  • [github] https://github.com/Mail-0/Zero“gives users the power to self-host their own email app while also integrating external services like Gmail and other email providers”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/.github/CONTRIBUTING.md“View and edit data with Drizzle Studio pnpm db:studio”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Self-host the core productweight 3

3 (weight) × 8 (quality) × 1.0 (full) = 24.0 of 30 max

  • [github] https://github.com/Mail-0/Zero“Self-Hosting Freedom – Run your own email app with ease.”
  • [github] https://github.com/Mail-0/Zero“⚙️ Self-Hosting Freedom – Run your own email app with ease.”
  • [github] https://github.com/Mail-0/Zero“gives users the power to **self-host** their own email app”
  • [github] https://github.com/Mail-0/Zero“⚙️ **Self-Hosting Freedom** – Run your own email app with ease.”
  • [github] https://github.com/Mail-0/Zero“gives users the power to self-host their own email app while also integrating external services like Gmail and other email providers”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/ROADMAP.md“Self-hosting capabilities”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Openness = 47.2 ÷ 100 × 100 = 47.2

Built-in AI57.8/100×0.15 of the PA blend

Inside-out: how agentic the product itself is for its users — built-in assistants, autonomous features.

Get AI-generated insights and suggestions from my data inside the productweight 2

2 (weight) × 7 (quality) × 1.0 (full) = 14.0 of 20 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about mailbox content - Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”
  • [community] https://hn.algolia.com/api/v1/items/43862892“Zero founder describes it as an AI-powered email client that auto-categorizes, summarizes threads, drafts replies, and lets users chat with their inbox; works on top of Gmail, in public beta.”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Set up automations that run autonomously in the backgroundweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Delegate tasks to a built-in AI assistant inside the productweight 3

3 (weight) × 8 (quality) × 1.0 (full) = 24.0 of 30 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about mailbox content - Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”
  • [community] https://hn.algolia.com/api/v1/items/43862892“Zero founder describes it as an AI-powered email client that auto-categorizes, summarizes threads, drafts replies, and lets users chat with their inbox; works on top of Gmail, in public beta.”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Operate the product with natural-language commandsweight 2

2 (weight) × 7 (quality) × 1.0 (full) = 14.0 of 20 max

  • [community] https://hn.algolia.com/api/v1/items/43862892“Zero founder describes it as an AI-powered email client that auto-categorizes, summarizes threads, drafts replies, and lets users chat with their inbox; works on top of Gmail, in public beta.”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Ask questions about mailbox content - Ask questions about specific email threads”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance”

Built-in AI = 52.0 ÷ 90 × 100 = 57.8

Automation8.6/100×0.15 of the PA blend

Depth of automation primitives — rules, scheduling, bulk operations, webhooks.

Perform bulk operations across many items at onceweight 2

2 (weight) × 5 (quality) × 0.6 (partial) = 6.0 of 20 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Bulk delete emails - Bulk archive emails”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Get email threads by ID - List emails in specific folders - Create and send new emails - Create email drafts - Send existing drafts - Delete emails”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Define rules that trigger actions automatically on eventsweight 3

3 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 30 max

  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Modify email labels”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Get email threads by ID - List emails in specific folders - Create and send new emails - Create email drafts - Send existing drafts - Delete emails”
  • [claimed-docs] https://raw.githubusercontent.com/Mail-0/Zero/staging/MCP.md“Compose emails with AI assistance - Ask questions about mailbox content - Ask questions about specific email threads - Web search using Perplexity AI”
  • [probe] https://github.com/Mail-0/Zero“PROBE runtime (recorded 2026-09-06): a keyless shallow git clone of Mail-0/Zero landed a REAL self-hostable source tree — repo-root MCP.md ('Zero MCP' server: get/send/draft/delete emails, labels, AI compose, mailbox Q&A, auth via Better Auth session token), AGENT.md agent-configuration docs, and docker-compose.db.yaml + docker-compose.prod.yaml for self-hosting.”

Schedule recurring jobs or workflowsweight 2

2 (weight) × 0 (quality) × 0.0 (none) = 0.0 of 20 max

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Version, review, and roll back my automationsweight 1

n/a — not applicable to this product: excluded from numerator and denominator

no evidence cited — the verdict rests on absence of evidence, re-checked on refresh

Automation = 6.0 ÷ 70 × 100 = 8.6