tengu_mcp_drop_invalid_tool_schemas
A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.259 and was gone by v2.1.260.
Default [], a list of hostnames. For an MCP server whose url hostname equals or is a subdomain of a listed entry (or for every server when the list contains ""), a tool whose input schema fails Claude Code's API-compatibility check is skipped and logged as Skipping tool "...": its input schema would be rejected by the Anthropic API. For other servers the tool is kept and only a warning is logged that requests including it may fail; servers without a string url only match "".
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.259 bundle, and it can be wrong.
In the changelogs
1Releases whose published page names tengu_mcp_drop_invalid_tool_schemas.
-
v2.1.216
MCP Tool Schema Validation Upgraded to JSON Schema Draft 2020-12
gate cited by this entry, found in this entry's text
Gate readings
1| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.216 read on another version | Not enough to say | no value returned | no value returned | not a boolean we can read |
Two arms, because they disagree: this account is the one account this site reads and anonymous is a baseline with no identity attached. A reading says nothing about your account, and off cannot rule out a rollout both readings sit outside of. What these readings can and cannot show.
Flag server, over time
12| Read as | Reading | From | Until | Version installed |
|---|---|---|---|---|
| anonymous | ["*"] | 2026-10-17T05:30:04Z | 2026-10-22T21:05:05Z | v2.1.302 to v2.1.308 |
| this account | ["*"] | 2026-09-10T21:47:12Z | 2026-10-22T21:05:05Z | v2.1.268 to v2.1.308 |
| anonymous | no longer carried | 2026-10-17T05:25:57Z | 2026-10-17T05:25:57Z | v2.1.302 |
| anonymous | ["*"] | 2026-08-23T18:00:04Z | 2026-10-17T05:10:04Z | v2.1.233 to v2.1.302 |
| this account | no longer carried | 2026-09-10T21:46:45Z | 2026-09-10T21:46:45Z | v2.1.268 |
| this account | ["*"] | 2026-09-08T20:36:15Z | 2026-09-10T17:40:05Z | v2.1.263 to v2.1.267 |
| this account | no longer carried | 2026-09-08T20:34:58Z | 2026-09-08T20:34:58Z | v2.1.265 |
| this account | ["*"] | 2026-09-06T02:40:05Z | 2026-09-08T18:45:05Z | v2.1.261 to v2.1.263 |
| this account | no longer carried | 2026-09-06T02:36:19Z | 2026-09-06T02:36:19Z | v2.1.263 |
| this account | ["*"] | 2026-08-23T18:30:05Z | 2026-09-06T01:55:04Z | v2.1.233 to v2.1.261 |
| this account | [] | 2026-08-20T04:25:04Z | 2026-08-23T18:00:04Z | v2.1.233 |
| anonymous | [] | 2026-08-20T04:00:05Z | 2026-08-23T15:25:05Z | v2.1.233 |
One row per unbroken stretch of one reading, newest first, from snapshots taken every twenty-five minutes or so. No longer carried is not off: it means the flag server stopped returning the gate at all, which is what a retired experiment looks like. The version column is what was installed when the reading was taken, not what caused it.
First cited
0No release's published evidence quotes this name. The ledger indexes the Evidence lines of every changelog on this site, so this says nobody here has ever quoted it; it says nothing about how old the name is.
Presence across releases
2Build by build
46One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the feature flag does. All feature flags.