ENABLE_TOOL_SEARCH

A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.138, including the newest one read.

Releases whose published page names ENABLE_TOOL_SEARCH.

1. v2.1.304 19 Oct 2026
   Tool search is tried through custom API endpoints and paused for a day if refused

   With a custom ANTHROPIC_BASE_URL, Claude Code now tries MCP tool search and turns it off for a day only if that endpoint refuses it

   found in this entry's text

2. v2.1.304 19 Oct 2026
   Tool search stays off for a conversation that has run without it

   Once a conversation has run without tool search, it stays off until you compact or clear it, unless ENABLE_TOOL_SEARCH=true is set

   found in this entry's text

3. v2.1.281 23 Sep 2026
   Managed-settings text for MCP tool search now says it is on by default for first-party providers

   The managed setting that turns on MCP tool search now says it is already on for the Claude API, Vertex AI, Bedrock and Bedrock Mantle

   found in this entry's text

4. v2.1.232 13 Aug 2026
   Environment variables read through one typed table instead of scattered process.env lookups

   Environment variables are now read through one typed table, with the same names and behaviour.

   found in this entry's text

5. v2.1.232 13 Aug 2026
   Tool search says once why it turned itself off

   Tool search logs why it disabled itself and refuses entirely against a non-Anthropic base URL.

   named in this entry, found in this entry's text

6. v2.1.227 10 Aug 2026
   ENABLE_TOOL_SEARCH=force now works from settings-composed environment

   ENABLE_TOOL_SEARCH=force now works when set through your settings, not just the shell.

   named in this entry, found in this entry's text

7. v2.1.224 7 Aug 2026
   Tool-search telemetry records the real mode and a finer skip reason

   Skipped tool-search events now report the real mode in effect and a more precise skip reason.

   named in this entry, found in this entry's text

8. v2.1.221 3 Aug 2026
   Tool search no longer disabled on Vertex AI

   Tool search now runs on Vertex AI instead of being refused outright.

   named in this entry, found in this entry's text

9. v2.1.9 15 Jan 2026
   ENABLE_TOOL_SEARCH Percentage Control

   found in this entry's text

The earliest release whose published evidence quoted ENABLE_TOOL_SEARCH was v2.1.9, 15 Jan 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.

One 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 environment variable does. All environment variables.