Files
codex/codex-rs/tools
jif-oai 672cc1f669 feat: wire extension tool bundles into core (#22147)
## Why

This is the next narrow step toward moving concrete tool families out of
core. After #22138 introduced `codex-tool-api`, we still needed a real
end-to-end seam that lets an extension own an executable tool definition
once and have core install it without the temporary `extension-api`
wrapper or a dependency on `codex-tools`.

`codex-tool-api` is the small extension-facing execution contract, while
`codex-tools` still has a different job: host-side shared tool metadata
and planning logic that is not “run this contributed tool”, like spec
shaping, namespaces, discovery, code-mode augmentation, and
MCP/dynamic-to-Responses API conversion

## What changed

- Moved the shared leaf tool-spec and JSON Schema types into
`codex-tool-api`, so the executable contract now lives with
[`ToolBundle`](c538758095/codex-rs/tool-api/src/bundle.rs (L19-L70)).
- Replaced the temporary extension-side tool wrapper with direct
`ToolBundle` use in `codex-extension-api`.
- Taught core to collect contributed bundles, include them in spec
planning, register them through
[`ToolRegistryBuilder::register_tool_bundle`](c538758095/codex-rs/core/src/tools/registry.rs (L653-L667)),
and dispatch them through the existing router/runtime path.
- Added focused coverage for contributed tools becoming model-visible
and dispatchable, plus spec-planning coverage for contributed function
and freeform tools.

## Verification

- Added `extension_tool_bundles_are_model_visible_and_dispatchable` in
`core/src/tools/router_tests.rs`.
- Added spec-plan coverage in `core/src/tools/spec_plan_tests.rs` for
contributed extension bundles.

## Related

- Follow-up to #22138
2026-05-11 16:42:29 +02:00
..

codex-tools

codex-tools is the host-side support crate for building, adapting, and planning tool sets outside codex-core.

It is deliberately not the API that external tool owners should depend on. Crates that contribute ordinary function tools through extensions should use codex-tool-api, which owns only that small executable-tool seam.

Today this crate owns the host-facing tool models and helpers that no longer need to live in core/src/tools/spec.rs or core/src/client_common.rs:

  • aggregate host models such as ToolSpec, ConfiguredToolSpec, LoadableToolSpec, ResponsesApiNamespace, and ResponsesApiNamespaceTool
  • host config and discovery models used while assembling tool sets, including ToolsConfig, discoverable-tool models, and request-plugin-install helpers
  • host adapters such as schema sanitization, MCP/dynamic conversion, code-mode augmentation, and image-detail normalization

That extraction is the first step in a longer migration. The goal is not to move all of core/src/tools into this crate in one shot. Instead, the plan is to peel off reusable pieces in reviewable increments while keeping compatibility-sensitive orchestration in codex-core until the surrounding boundaries are ready.

Vision

Over time, this crate should hold host-side tool machinery that is shared by multiple consumers, for example:

  • host-visible aggregate tool models
  • tool-set planning and discovery helpers
  • MCP and dynamic-tool adaptation into Responses API shapes
  • code-mode compatibility shims that do not depend on codex-core
  • other narrowly scoped host utilities that multiple crates need

The corresponding non-goals are just as important:

  • do not become the extension-facing authoring API for executable tools
  • do not move codex-core orchestration here prematurely
  • do not pull Session / TurnContext / approval flow / runtime execution logic into this crate unless those dependencies have first been split into stable shared interfaces
  • do not turn this crate into a grab-bag for unrelated helper code

Migration approach

The expected migration shape is:

  1. Keep ordinary contributed function-tool authoring in codex-tool-api.
  2. Move host-side planning/adaptation helpers here when they no longer need to stay coupled to codex-core.
  3. Leave compatibility-sensitive adapters in codex-core while downstream call sites are updated.
  4. Only extract higher-level host infrastructure after the crate boundaries are clear and independently testable.

Crate conventions

This crate should start with stricter structure than core/src/tools so it stays easy to grow:

  • src/lib.rs should remain exports-only.
  • Business logic should live in named module files such as foo.rs.
  • Unit tests for foo.rs should live in a sibling foo_tests.rs.
  • The implementation file should wire tests with:
#[cfg(test)]
#[path = "foo_tests.rs"]
mod tests;

If this crate starts accumulating code that needs runtime state from codex-core, that is a sign to revisit the extraction boundary before adding more here.