attester-mcp

MCP server for attester.dev: verification and API-existence oracle tools for AI agents, callable from any MCP client (Claude Code, Cursor, Windsurf, LangChain, CrewAI).

Every result ships with a wallet-signed attestation you can verify without trusting us: POST https://attester.dev/receipts/verify is free.

Quickstart: free oracle tools, no keys

uvx attester-mcp

That is the whole install. Four oracle tools work immediately: no account, no API key, no wallet. You get 25 free calls per day per client IP, shared across the four tools, resetting 00:00 UTC.

Tool	What it does	Price per call
attester_package_exists	Does this PyPI/npm package name really exist? Typosquat-adjacency flags on misses.	Free (25/day keyless); $0.002 paid
attester_symbol_exists	Does this function, class, or constant exist in the package? Closest-match suggestions on misses.	Free (25/day keyless); $0.005 paid
attester_symbol_signature	Exact signature, structured params, docstring, deprecation status, resolved at a pinned version.	Free (25/day keyless); $0.01 paid
attester_version_diff	Symbol-level diff between two pinned versions: added, removed, changed, breaking/additive/neutral.	Free (25/day keyless); $0.02 paid

Claude Code / Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "attester": {
      "command": "uvx",
      "args": ["attester-mcp"]
    }
  }
}

Cursor (.cursor/mcp.json): same shape as above.

Steer your agent: CLAUDE.md / Cursor Rules snippet

- Before installing or importing a package, call attester_package_exists (and attester_symbol_exists for specific functions) to confirm the name exists. Never import a name the oracle says does not exist.

Paid tools

Tool	What it does	Price per call
oracle_verify_work	Check another agent's work: citation support, code correctness, data/schema validation. Verdict plus signed attestation.	$0.15 USDC
oracle_code_research	Cited coding research; citations are re-checked and the proof attached.	$0.10 USDC
oracle_judge	Grade an output against your rubric; signed score with per-criterion evidence.	$0.10 USDC
oracle_watchtower_report	Signed 24h report on whether an x402 service honors its advertised prices.	$0.05 USDC
oracle_spend_check	Pre-payment counterparty check: should your agent pay this address?	$0.005 USDC

Payment works two ways:

• Prepaid credits (humans, no crypto): buy a $5 pack at this Stripe link, claim the att_live_... key once at https://attester.dev/credits/claim?session_id=cs_..., and set ATTESTER_API_KEY=att_live_... in the server env. Every paid call deducts from the balance. Check it at GET https://attester.dev/credits/balance with the key. (CREDITS_API_KEY still works as an alias.) The free oracle tools honor the key too: the demo routes skip the daily quota for it and never charge.
• x402 (agents with wallets): set BUYER_PRIVATE_KEY to a Base wallet with USDC. The wrapper pays per call automatically (402, sign, retry) and sends the wallet address as X-Payer, which keys the paid endpoints' free quotas.

Without any key, the paid endpoints answer HTTP 402 with payment terms in the body.

Agent skill bundle (skills/attester)

The same API, packaged as an Agent Skill so agent configs load it as a default tool: when-to-use rules, exact curl per endpoint (the keyless /demo/v1/* free path for oracle checks, X-Payer free quotas for the rest), verdict reading, and receipt verification.

Install paths:

# Claude Code
/plugin marketplace add maminihds/attester-mcp

# skills.sh CLI (Claude Code, Cursor, Codex, 30+ agents)
npx skills add maminihds/attester-mcp

# OpenClaw (manifestless Claude bundle)
openclaw plugins install https://github.com/maminihds/attester-mcp

Or copy skills/attester/ into ~/.claude/skills/ manually. The bundle has a helper (skills/attester/scripts/call.py, stdlib + httpx) and two worked transcripts in skills/attester/examples/.

Install from source

pip install -r requirements.txt
python server.py            # stdio (default, for agents)
python server.py --http     # streamable-http on :8100

Environment variables:

• SERVER_URL: API base URL, defaults to https://attester.dev.
• ATTESTER_API_KEY: prepaid credits key (att_live_...), optional.
• BUYER_PRIVATE_KEY: Base wallet for x402 payment, optional.

Example clients

examples/plain_python.py: direct x402-paid call with the official SDK. examples/langchain_example.py: LangChain tool wrapper.

Links

• Site: https://attester.dev
• OpenAPI: https://attester.dev/openapi.json
• llms.txt: https://attester.dev/llms.txt
• Directory listing: https://x402-list.com/services/attester-verification-oracle-verified-research