## Summary
- When `WEB_SEARCH_DRIVER` is set to a non-native driver (e.g. `EXA`),
the `web_search` action tool was only listed in the tool catalog and had
to be discovered via `learn_tools` before use. Worse,
`system-prompt-builder` explicitly instructed the model **not** to call
`web_search` whenever it wasn't in the preloaded set, so even setting
`EXA_API_KEY` correctly resulted in the model never calling Exa.
- Fix: preload `web_search` from the registry alongside the other action
tools when `shouldUseNativeSearch()` is false, mirroring how native
provider search is already injected into `directTools`. The system
prompt builder picks this up automatically and advertises `web_search`
as a ready-to-use tool.
- Unrelated: pass `isSystemBuild: true` to the messageThread upgrade
command's migration build.
## Test plan
- [ ] With `WEB_SEARCH_DRIVER=EXA` and `EXA_API_KEY` set, ask the chat
agent for current/news information and verify it calls `web_search`
directly (not via `learn_tools` / `execute_tool`) and that Exa is hit.
- [ ] With `WEB_SEARCH_PREFER_NATIVE=true`, verify native provider
search is still used and the action tool is not preloaded.
- [ ] With `WEB_SEARCH_DRIVER=DISABLED`, verify behavior is unchanged
(`shouldUseNativeSearch()` returns true → no Exa preload).
- [ ] Run the 1-21 fix-message-thread-view-and-label-identifier upgrade
command on a workspace and confirm the migration builds/runs as a system
build.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Félix Malfait
7aed9291cd