## Why Tool registration used to bind a tool name to a handler externally, which left ownership split between the registry plan and the handler implementation. Some built-in handlers also multiplexed multiple in-core tools by switching on the invoked tool name internally. This moves the registry identity onto the handler itself and makes built-in multi-tool areas use separate concrete handlers, so each registered handler instance owns exactly one tool name and one dispatch path. ## What Changed - Added `ToolHandler::tool_name()` and changed `ToolRegistryBuilder::register_handler` to derive the registry key from the handler. - Split built-in multiplexed handlers into concrete per-tool handlers for unified exec, shell/local shell/container exec, MCP resources, goal tools, and agent job tools. - Kept name-carrying handler instances only where the runtime target is inherently external or dynamic, such as MCP tools, dynamic tools, and unavailable placeholders. - Updated `ToolHandlerKind` and registry-plan construction so plan entries map directly to concrete handler registrations. ## Verification - `cargo test -p codex-tools tool_registry_plan` - `cargo test -p codex-core --lib tools::registry_tests` - `just fix -p codex-tools` - `just fix -p codex-core`
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:
JsonSchemaAdditionalPropertiesToolDefinitionToolSpecConfiguredToolSpecResponsesApiToolFreeformToolFreeformToolFormatLoadableToolSpecResponsesApiWebSearchFiltersResponsesApiWebSearchUserLocationResponsesApiNamespaceResponsesApiNamespaceTool- code-mode
ToolSpecadapters andexec/waitspec builders - MCP resource and
test_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_searchandrequest_plugin_install 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_loadable_tool_spec()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.