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Witness MCP Tool Surface Drift Detector
x402
Witness MCP Tool Surface Drift Detector is a paid API for AI agents from witness.holoweave.org, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).
Compares an MCP server's current tools/list against a signed baseline digest and returns a cryptographically signed attestation listing every tool added, removed, or silently redefined.
Price / call$0.01
Success—
StatusDown
How this service works
Web bot auth debugging for AI agents, priced per check at $0.01. RFC 7638 keyid thumbprint verification, RFC 9421 Ed25519 signature verification, and per-verifier acceptance rules. Signed attestations, published fixtures, sources with dates.
Output
A JSON object containing an ed25519-signed attestation with a verdict ('pass' or 'fail'), the endpoint name, and a findings array. Each finding includes a code (e.g. TOOL_CHANGED, TOOL_ADDED, TOOL_REMOVED), a severity level, and a human-readable detail string explaining what changed. The signature includes the algorithm, base64-encoded value, and key ID for independent verification.
Example use cases
Nightly MCP integrity audit
“Every night, diff the MCP server at https://agents.myplatform.io/mcp against the baseline digest we pinned on Monday and alert me if any tools were added, removed, or had their descriptions rewritten — I need a signed attestation I can log.”
Detect silent tool redefinition
“I'm worried someone may have rewritten the 'search' tool's description on our MCP server without changing the schema — can you hit https://mcp.internal.co/stream and compare it against our stored baseline to see if anything was silently redefined?”
Pre-deployment tool surface check
“Before we promote this MCP server build to production, run a diff between its current tools/list and the approved baseline digest from our last release and tell me the verdict with a signed proof I can attach to the deployment record.”
Technical details
Endpoint
POSThttps://witness.holoweave.org/v1/mcp-diffWhen to prefer
Choose this endpoint when you need a cryptographically signed, auditable record of whether an MCP server's tool surface has changed — especially for supply-chain security, compliance logging, or catching silent prompt-injection via tool description rewrites. Prefer it over manual diffing or unattested comparisons when you need a tamper-evident artifact. It's the right choice when you already have a baseline digest from a prior /v1/mcp-digest pin call and want to detect drift with non-repudiable evidence.
Side effects
- Unreachable MCP URL returns connection error with no attestation
- Malformed baseline digest causes 400 validation error
- MCP server returns non-standard tools/list format causing parse failure
- Baseline missing required 'tools' field triggers schema rejection
- Network timeout if target MCP server is slow to respond
- Invalid or expired signing key returns attestation with unverifiable signature
Output
Schema · Response
{
"example": {
"signature": {
"alg": "ed25519",
"value": "base64...",
"key_id": "aw-attest-2026-08"
},
"attestation": {
"verdict": "fail",
"endpoint": "mcp-diff",
"findings": [
{
"code": "TOOL_CHANGED",
"detail": "\"search\" has the same name and a different definition. A rewritten description is still schema-valid, so a conformance check will not see this.",
"severity": "change"
}
]
}
}
}Tags
x402
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