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answering

Assay is answering right now. Last checked 4 min ago. It exposes 4 tools.

A2A & MCP Pre-Flight Security: SHA-256 tool schema rug-pull detection and liveness grades.

Uptime history 10 days of history
10 days agonow
100.0%
Uptime 24h
92 of 92 checks
4
Tools
read from the server
203 ms
Response time
average over 24h
open, no key
Access
streamable-http

What changed 39

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 17 October 2026. No other catalogue keeps this.

19 Oct 4 tools changed the parameters they ask for8 times that day assay_get_ledger_policy, assay_preflight, assay_probe and 1 more
19 Oct a tool changed version7 times that day
19 Oct 4 tool descriptions were rewritten assay_get_ledger_policy, assay_preflight, assay_probe and 1 more
18 Oct 4 tool descriptions were rewritten assay_get_ledger_policy, assay_preflight, assay_probe and 1 more
18 Oct 3 tools changed the parameters they ask for assay_get_ledger_policy, assay_preflight, assay_verify_delivery
18 Oct a tool changed version2 times that day
17 Oct 3 tool descriptions were rewritten5 times that day assay_preflight, assay_probe, assay_verify_delivery
17 Oct 3 tools changed the parameters they ask for assay_preflight, assay_probe, assay_verify_delivery
17 Oct a tool changed version2 times that day
17 Oct a tool appeared assay_get_ledger_policy
and 14 more, back to 17 October 2026

Nothing serious here today

Today is the operative word: we check Assay every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Three servers free · no card

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 4 min ago.

run in your terminal
claude mcp add assay --transport http https://assay-207908449630.us-central1.run.app/mcp
Settings → Connectors → Add custom connector, then paste this address
https://assay-207908449630.us-central1.run.app/mcp
~/.codex/config.toml
[mcp_servers.assay]
url = "https://assay-207908449630.us-central1.run.app/mcp"
.cursor/mcp.json
{
  "mcpServers": {
    "assay": {
      "url": "https://assay-207908449630.us-central1.run.app/mcp"
    }
  }
}
.vscode/mcp.json
{
  "servers": {
    "assay": {
      "type": "http",
      "url": "https://assay-207908449630.us-central1.run.app/mcp"
    }
  }
}

Available tools 4

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

assay
assay_get_ledger_policy
Retrieve historical conformance observations and manage pinned SHA-256 tools/list policy hashes in the Assay ledger for a target endpoint. When expected_tools_hash is provided, it pins that 64-hex digest as the target's baseline policy and compares it against the latest stored observation; when omitted, it returns the stored dossier and last 20 drift observations without network probing unless the target is unindexed. Idempotent; first 5 calls/IP are free. Use to audit historical drift or pin mcp-lock.json hashes; for live pre-execution gating use assay_preflight; for live re-indexing use assay_probe; for post-payment SLA receipts use assay_verify_delivery. Example: target='https://agentdiet-72343955726.us-central1.run.app/mcp'.
assay_preflight
Gate a remote MCP, A2A, or x402 endpoint before calling or paying it by probing live JSON-RPC reachability, hashing tools/list (SHA-256), and scanning for prompt-injection poisoning. When expected_tools_hash is provided, any mismatch against the live tools/list digest forces verdict='deny' to block silent schema rug-pulls; when omitted, verdict reflects liveness and injection safety alone. Read-only gate; first 5 calls/IP are free and quota-exceeded calls return a 402 top-up prompt. Use before tool execution or payment; to register or refresh public leaderboard telemetry use assay_probe; to read or pin stored policy hashes use assay_get_ledger_policy; after payment use assay_verify_delivery. Example: target='https://agentdiet-72343955726.us-central1.run.app/mcp'.
assay_probe
Register a new remote MCP, A2A, or x402 endpoint or refresh its public Assay Observatory dossier by running a live HTTP, agent-card, and JSON-RPC tools/list inspection without policy gating. Target must be a public HTTPS origin (private IPs are rejected with a 400 error); each call appends a timestamped observation and increments rug_pulls if tools_hash drifted since the prior stored observation. Writes to the public ledger; first 5 calls/IP are free and retries are idempotent on steady schemas. Use to onboard or re-index a server; for pre-call allow/deny gating use assay_preflight; for historical observations or hash pinning use assay_get_ledger_policy; for post-payment disputes use assay_verify_delivery. Example: target='https://agentdiet-72343955726.us-central1.run.app/mcp'.
assay_verify_delivery
Audit a paid x402 or A2A provider after payment to confirm delivery or prove an SLA breach with an HMAC-SHA256 signed receipt. Passing status_code >= 500 forces verdict='sla_breach_confirmed' even if the live re-probe succeeds, while passing tx_hash cryptographically binds your Base or Solana payment signature into the receipt (omitting tx_hash still verifies liveness and issues a probe-bound receipt). Non-destructive; first 5 calls/IP are free and failed target connections do not throw tool errors. Use only after paying a provider; before payment use assay_preflight; for public indexing use assay_probe; for policy history use assay_get_ledger_policy. Example: target='https://agentdiet-72343955726.us-central1.run.app/mcp'.

Endpoints

URLTransportStateLatencyChecked
https://assay-207908449630.us-central1.run.app/mcp streamable-http answering 200 ms 4 min ago

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Assay — questions

Answers built from our own checks of this server.

What can Assay do?
It exposes 4 tools, read directly from the server on our last check. Among them: assay_get_ledger_policy, assay_preflight, assay_probe, assay_verify_delivery. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →
Is Assay working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 203 ms. The bar chart above shows every period we have measured.
How do I connect Assay?
Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does Assay need an API key?
No. Assay completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 4 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is Assay?
It answers our handshake in 203 ms on average, which is faster than 78% of all working MCP servers we measure. That puts it in the quick quarter of the ecosystem. The comparison comes from our own checks across the whole registry, every 15 minutes.