Daily MCP Tool Drifts- 8,931 of 12,391 drifted with no version bump

Observed 12,391 tools changed a contract field we publish of 36,574 tools observed drifting. The remainder changed in ways we record but do not publish, predominantly description-only edits. Servers affected2,191 Safety-relevant contract changesChanges that touch a safety-relevant field - not confirmed vulnerabilities.7,239 The Drift Report · as of 2026-08-18 Since tracking began, the crawler has observed 12,391 tools across 2,191 servers change their contract, 7,239 of them in a safety-relevant way.Most drift is harmless: 5,507 just added an optional parameter, and a gate should proceed silently on those. Not crying wolf on benign change is the point. Here are the ones that would actually surprise an agent mid-session. 354 tools flipped a read-only hint toward write, delete, or send (the "read tool quietly became a write tool" case). 281 tools added a newly-required parameter, which breaks an agent still calling with last week’s arguments. 476 tools removed a parameter your agent may still be sending. 2,633 tools changed their output schema, the shape of what comes back. 684 tools narrowed a constraint, a tighter enum or range than you pinned. 360 tools changed a parameter’s type. Auth is not built to catch this class of change. A server that edits a tool’s contract keeps its API key, its allow-list entry, and its name in your config - access control answers who may call a tool, not whether the tool still does what it declared when you connected it. The failure mode with MCP is rarely “I connected a bad server on day one.” It is “I connected a good server that changed on day 30.” A contract diff, observed between snapshots. Not a safety verdict, not a claim any change is malicious, and not prevention: the ledger observes, the gate holds. Every entry is a fingerprint, never a named server. Numbers update daily and are self-verifiable at /api/v1/ledger. pin and HOLD drift in your setup → Honesty These are contract changes mcpindex's crawler OBSERVED between two daily registry snapshots - a contract diff, not a safety verdict, and not an in-path prevention (that is the gate). Absence from this list is not a clean bill of health: a private or un-crawled tool never appears here. No server pays to be listed or de-listed. Generated Tue, 18 Aug 2026 20:01:35 GMT Events Tools and servers are shown as content fingerprints, not names: mcpindex reports that a contract changed without publicly naming a specific server. A dash means no server fingerprint was recorded. Contract changes the crawler observed, by tool and server fingerprint, with last-seen time, what changed (the contract-diff kind), and whether the change touched a safety-relevant field. Tool fingerprintServer fingerprintLast seenWhat changedSafety bab5fd056c7c...f96bcac56f4b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramconstraint-narrowedoutput-schema-changed safety-relevant diff 5f745caefdeb...43e7ace9e4ef...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 734425d97508...f96bcac56f4b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 2d334bc7f061...ee6db032196e...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 3d4fcd3d21dd...ce46b383273e...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 68c4502d7b4d...ce46b383273e...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 34c5b0e1da34...ce46b383273e...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramconstraint-narrowedoutput-schema-changed safety-relevant diff 740fc8c99f54...21023f01f1d0...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-added Not safety-relevant- c2f533b290a9...21023f01f1d0...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-added Not safety-relevant- f573f76728e0...ee6db032196e...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 5a9fa4b24cb6...ce46b383273e...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramconstraint-narrowedoutput-schema-changed safety-relevant diff c5329008c3b8...a9c6b4e9ef7b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramremoved-param safety-relevant diff e3e3f1e5affa...a9c6b4e9ef7b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramremoved-param safety-relevant diff 1e85bafa093e...a9c6b4e9ef7b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramremoved-param safety-relevant diff fc4854514648...c49c52abc646...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramadded-required-paramoutput-schema-addedoutput-schema-changedremoved-param safety-relevant diff 08f5c2caf85f...c49c52abc646...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-addedremoved-param safety-relevant diff 652df0dc1525...e391f61e6bc1...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changedtype-changed safety-relevant diff c9c9e65a89a9...e391f61e6bc1...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changedtype-changed safety-relevant diff 0c8cea45f0b7...e391f61e6bc1...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changedtype-changed safety-relevant diff ba5fe8fe8386...5bf38ceaa27d...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-added Not safety-relevant- 7e56b74409b7...5bf38ceaa27d...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-added Not safety-relevant- 3370525bce44...5bf38ceaa27d...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-added Not safety-relevant- f3f3bfa248bd...511299da1f6a...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- bd516ede26b3...778cd3cf8585...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 88a9d439f996...778cd3cf8585...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff f38ebaead41d...9cab4e94690c...Tue, 18 Aug 2026 17:00:00 GMT enum-values-removedtype-changed safety-relevant diff 2cf8cd2cceb7...e391f61e6bc1...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff c343f5e0db0a...e244fd3531d5...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 6c7ed74e7c90...b5f31717ca91...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramenum-values-removedremoved-param safety-relevant diff bf805ba8c52c...aea425e9d430...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changedtype-changed safety-relevant diff 3dc087e15e40...c49c52abc646...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-addedoutput-schema-changedtype-changed safety-relevant diff 119cb278c4d2...c49c52abc646...Tue, 18 Aug 2026 17:00:00 GMT output-schema-addedoutput-schema-changedremoved-param safety-relevant diff 66088bb696e7...c49c52abc646...Tue, 18 Aug 2026 17:00:00 GMT output-schema-addedremoved-paramtype-changed safety-relevant diff 08faae2f9ffa...778cd3cf8585...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 3104efdcf99d...d3a356891b93...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- 64b5ced10ef4...d24a22ef4021...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- db42f34d463a...83460e45cca7...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- 60a7f3e7a42c...8578c6d1919f...Tue, 18 Aug 2026 17:00:00 GMT tool-removed (toolset replaced) safety-relevant diff 22daea1d9ee9...8578c6d1919f...Tue, 18 Aug 2026 17:00:00 GMT tool-removed (toolset replaced) safety-relevant diff 97a885667af7...8578c6d1919f...Tue, 18 Aug 2026 17:00:00 GMT tool-removed (toolset replaced) safety-relevant diff 6d36a0894eda...4984e07b904f...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changedtool-removed safety-relevant diff 41358708a4e7...c49c52abc646...Tue, 18 Aug 2026 17:00:00 GMT output-schema-addedoutput-schema-changed safety-relevant diff 7d02c1266b8b...3c247630136e...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramadded-required-paramoutput-schema-changedtype-changed safety-relevant diff 7dca7923b5a1...3c247630136e...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 8ccd2a64476e...e828f2d57016...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-addedremoved-param safety-relevant diff bc7909e38eae...30153f6df04b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramtype-changed safety-relevant diff e5e7a0233477...08c40bbfbf0d...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 365567189fa3...0b56a2a1efa8...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff c3acf3deca94...0b56a2a1efa8...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 1e8c1494fe46...96c9f6b70c29...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- 6a9d084a3888...ac5975b9aa7b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- 652083290e2d...0f42e5fa1bd5...Tue, 18 Aug 2026 17:00:00 GMT output-schema-added Not safety-relevant- a3a29c587c27...0f42e5fa1bd5...Tue, 18 Aug 2026 17:00:00 GMT output-schema-added Not safety-relevant- 031a091a2a12...0f42e5fa1bd5...Tue, 18 Aug 2026 17:00:00 GMT output-schema-added Not safety-relevant- 67f52398e408...0f42e5fa1bd5...Tue, 18 Aug 2026 17:00:00 GMT output-schema-added Not safety-relevant- 3aa75d39faf1...0f42e5fa1bd5...Tue, 18 Aug 2026 17:00:00 GMT output-schema-added Not safety-relevant- 7e6a4862bb2d...4dd149593847...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff c512fff5217f...4dd149593847...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 3d898046e89b...4dd149593847...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 351713fb4aef...4dd149593847...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 2dcd3157f9df...4dd149593847...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff e7aad13d76d6...4dd149593847...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 29bbadfd4d4b...778cd3cf8585...Tue, 18 Aug 2026 17:00:00 GMT output-schema-changed safety-relevant diff 6fb8363424b9...7b21d969f00b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- 41db3ee1d672...7b21d969f00b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 97cc6b0e799b...7b21d969f00b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 31dd502a13d9...7b21d969f00b...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff 5b6334ea5a72...830351b0e9a4...Tue, 18 Aug 2026 17:00:00 GMT enum-values-removed safety-relevant diff 9888d120d2b0...550d0b59e3de...Tue, 18 Aug 2026 17:00:00 GMT output-schema-added Not safety-relevant- fb83fe06b0ff...550d0b59e3de...Tue, 18 Aug 2026 17:00:00 GMT output-schema-added Not safety-relevant- 4b38526fe8ee...753e2a6a4205...Tue, 18 Aug 2026 17:00:00 GMT tool-removed safety-relevant diff f18e8d84612c...21dd20eaf8ab...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- 979be13d1928...21dd20eaf8ab...Tue, 18 Aug 2026 17:00:00 GMT added-optional-paramoutput-schema-changed safety-relevant diff eec4dc1ba8a9...f7c208c08ae9...Tue, 18 Aug 2026 17:00:00 GMT added-optional-param Not safety-relevant- 9528d0bc2ecf...f7c208c08ae9...Tue, 18 Aug 2026 17:00:00 GMT tool-removed safety-relevant diff 6fe8a4f63280...f7c208c08ae9...Tue, 18 Aug 2026 17:00:00 GMT tool-removed safety-relevant diff fa3aa8295bc6...f7c208c08ae9...Tue, 18 Aug 2026 17:00:00 GMT tool-removed safety-relevant diff ee755bb924da...503aff61a32b...Tue, 18 Aug 2026 17:00:00 GMT tool-removed safety-relevant diff 96185a137b6c...503a [truncated for AI cost control]