MCP Census developer portal

The MCP Census developer resources for agents and CI: API keys, REST, MCP, OpenAPI, auth, and watch webhooks. Public sandbox is the live API under the free daily cap.

Product · The MCP Census · mcpcensus.com

API docs

Human REST + MCP reference, install commands, watch events.

API keys

Free account key, 1,000 credits/month. No card.

When to use

Jobs The MCP Census is right for, and how to call it.

Quickstart

Optional: mint a key at /account (GitHub or email). Header: x-api-key.
Agents: add the MCP server https://api.mcpcensus.com/mcp (see prompt.md).
REST: GET https://api.mcpcensus.com/v1/search?q=github then POST /v1/preflight or GET /v1/stamp with one exact canonical name — or POST /v1/audit with your whole .mcp.json (one verdict line per entry, exit code for CI; contract: /agent-setup/audit).
Stop on BLOCK. Ask a human on REVIEW. PASS is not a sandbox. Never install from a Census result alone.

Config audit

Post a whole MCP config and get one verdict per server. Reads .mcp.json, mcp.json, claude_desktop_config.json, Cursor and VS Code mcpServers / servers, and Codex config.toml. Each entry resolves by URL, npm or PyPI package, or canonical name, then gets PASS, REVIEW, BLOCK or UNKNOWN with the reasons. UNKNOWN means the Census has no row for it, not that it is fine. Contract: /agent-setup/audit.md.

curl -s -X POST https://api.mcpcensus.com/v1/audit \
  -H "content-type: application/json" -H "accept: text/plain" \
  --data-binary @.mcp.json

Keyless: one config of up to 25 entries per IP per UTC day. With a key: 1 credit per config per UTC day, repeats free, up to 100 entries.
exit_code 0 all PASS, 1 any BLOCK; ?strict=1 makes REVIEW or UNKNOWN exit 2. Also in the x-census-exit-code header.
MCP twin: census_audit_config. Resolver only, unmetered: POST /v1/resolve.
Change feed: GET /v1/changes?since=<cursor> returns what the crons observed since your last poll — new servers, remote down/up, tools changed, health and verification flips, endpoint moved, registry status. Unmetered, poll hourly. Contract: /agent-setup/changes.md.

Rule line for your agent

Put this one line in CLAUDE.md, AGENTS.md or .cursor/rules. It is the whole recurrence mechanism:

Before adding, enabling or calling any MCP server, run a Census stamp. Stop on BLOCK. Ask on REVIEW.

Install badges

On-ramps only. The hooks in the plugins are what fire every session.

Claude Code: claude mcp add --transport http mcp-census https://api.mcpcensus.com/mcp
Codex: codex mcp add mcp-census --url https://api.mcpcensus.com/mcp
Cursor: Add to Cursor (deeplink; or web handoff)
VS Code: Install in VS Code · Insiders
Any agent: https://api.mcpcensus.com/mcp (streamable HTTP). Skills: npx skills add mcpcensus/skills (repo publish pending — see prompt.md).
CI: census-preflight.yml posts your MCP config files to /v1/audit on every PR that touches them.

Sandbox

There is no separate staging host. The public MCP Census API is the sandbox.

Anonymous: 10 unique lookups/day per IP.
Free account: 1,000 credits/UTC month. Builder $19/mo, pack $9, team $49/mo. Prices.
Search/lookup 1 credit, preflight/stamp 5, watch 10, config audit 1 per config per UTC day. Repeats same UTC day are free. Empty wallet is HTTP 402 payment_required.
Unmetered: GET /v1/stats, GET /v1/recent, GET /v1/coverage, GET /v1/policies, census_credits.

curl -s https://api.mcpcensus.com/v1/stats
curl -s "https://api.mcpcensus.com/v1/search?q=github"
curl -s https://api.mcpcensus.com/v1/policies

Auth

API keys live on the account at mcpcensus.com/account. Send x-api-key. Anonymous calls work until the daily cap. Lost keys are emailed to the account address from the API page — the key is never shown in HTML.

MCP server

Endpoint: https://api.mcpcensus.com/mcp (streamable HTTP). Required: census_search then census_preflight or census_stamp before connect. Also census_credits, census_lookalikes. Full list: llms.txt.

Webhooks

Watch one server: POST https://api.mcpcensus.com/v1/watch (API key). Events fire only on observed transitions: remote down/up, health, verification legs, security. Headers: X-Census-Event, X-Census-Signature, X-Census-Watch-Id. Docs: /api#watch.

Agent files

/llms.txt — agent map, including when to use The MCP Census
/agent-instructions.md — when-to-use + call pattern
/agent-setup/prompt.md — install commands per host
/agent-setup/census-preflight.yml — CI gate (fail on BLOCK, warn on REVIEW)
/pricing — credits in USD
/openapi.json — OpenAPI
/bot — crawler identity

Contact: [email protected]. Product name: The MCP Census. Domain: mcpcensus.com.