## Why Follow-up to #16379. `codex-rs/core/src/tools/spec.rs` and the corresponding handlers still owned several pure tool-definition helpers even though they do not need `codex-core` runtime state. Keeping that spec-only logic in `codex-core` keeps the crate boundary blurry and works against the guidance in `AGENTS.md` to keep shared tooling out of `codex-core` when possible. This change takes another step toward a dedicated `codex-tools` crate by moving more metadata and schema-building code behind the `codex-tools` API while leaving the actual tool execution paths in `codex-core`. ## What Changed - Added `codex-rs/tools/src/apply_patch_tool.rs` to own `ApplyPatchToolArgs`, the freeform/json `apply_patch` tool specs, and the moved `tool_apply_patch.lark` grammar. - Updated `codex-rs/tools/BUILD.bazel` so Bazel exposes the moved grammar file to `codex-tools`. - Moved the `request_user_input` availability and description helpers into `codex-rs/tools/src/request_user_input_tool.rs`, with the related unit tests moved alongside that business logic. - Moved `request_permissions_tool_description()` into `codex-rs/tools/src/local_tool.rs`. - Rewired `codex-rs/core/src/tools/spec.rs`, `codex-rs/core/src/tools/handlers/apply_patch.rs`, and `codex-rs/core/src/tools/handlers/request_user_input.rs` to consume the new `codex-tools` exports instead of local helper code. - Removed the now-redundant helper implementations and tests from `codex-core`, plus a couple of stale `client_common` re-exports that became unused after the move. ## Testing - `cargo test -p codex-tools` - `cargo test -p codex-core tools::spec::tests` - `cargo test -p codex-core tools::handlers::apply_patch::tests`
codex-tools
codex-tools is intended to become the home for tool-related code that is
shared across multiple crates and does not need to stay coupled to
codex-core.
Today this crate is intentionally small. It currently owns the shared tool
schema and Responses API tool primitives that no longer need to live in
core/src/tools/spec.rs or core/src/client_common.rs:
JsonSchemaAdditionalPropertiesToolDefinitionToolSpecConfiguredToolSpecResponsesApiToolFreeformToolFreeformToolFormatToolSearchOutputToolResponsesApiWebSearchFiltersResponsesApiWebSearchUserLocationResponsesApiNamespaceResponsesApiNamespaceTool- code-mode
ToolSpecadapters andexec/waitspec builders - JS REPL spec builders
- MCP resource,
list_dir, andtest_sync_toolspec builders - local host tool spec builders for shell/exec/request-permissions/view-image
- collaboration and agent-job
ToolSpecbuilders for spawn/send/wait/close,request_user_input, and CSV fanout/reporting - discoverable-tool models, client filtering, and
ToolSpecbuilders fortool_searchandtool_suggest parse_tool_input_schema()parse_dynamic_tool()parse_mcp_tool()create_tools_json_for_responses_api()mcp_call_tool_result_output_schema()tool_definition_to_responses_api_tool()dynamic_tool_to_responses_api_tool()mcp_tool_to_responses_api_tool()mcp_tool_to_deferred_responses_api_tool()augment_tool_spec_for_code_mode()tool_spec_to_code_mode_tool_definition()
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 tool-facing primitives that are shared by multiple consumers, for example:
- schema and spec data models
- tool input/output parsing helpers
- tool metadata and compatibility shims that do not depend on
codex-core - other narrowly scoped utility code that multiple crates need
The corresponding non-goals are just as important:
- do not move
codex-coreorchestration 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:
- Move low-coupling tool primitives here.
- Switch non-core consumers to depend on
codex-toolsdirectly. - Leave compatibility-sensitive adapters in
codex-corewhile downstream call sites are updated. - Only extract higher-level tool infrastructure after the crate boundaries are clear and independently testable.
That means it is normal for codex-core to temporarily re-export types or
helpers from codex-tools during the transition.
Crate conventions
This crate should start with stricter structure than core/src/tools so it
stays easy to grow:
src/lib.rsshould remain exports-only.- Business logic should live in named module files such as
foo.rs. - Unit tests for
foo.rsshould live in a siblingfoo_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.