stacked on #17402.
MCP tools returned by `tool_search` (deferred tools) get registered in
our `ToolRegistry` with a different format than directly available
tools. this leads to two different ways of accessing MCP tools from our
tool catalog, only one of which works for each. fix this by registering
all MCP tools with the namespace format, since this info is already
available.
also, direct MCP tools are registered to responsesapi without a
namespace, while deferred MCP tools have a namespace. this means we can
receive MCP `FunctionCall`s in both formats from namespaces. fix this by
always registering MCP tools with namespace, regardless of deferral
status.
make code mode track `ToolName` provenance of tools so it can map the
literal JS function name string to the correct `ToolName` for
invocation, rather than supporting both in core.
this lets us unify to a single canonical `ToolName` representation for
each MCP tool and force everywhere to use that one, without supporting
fallbacks.
## Why
The previous `codex-tools` migration steps moved the shared schema
models, local-host specs, collaboration specs, and related adapters out
of `codex-core`, but `core/src/tools/spec.rs` still contained a grab bag
of pure utility tool builders. Those specs do not need session state or
handler logic; they only describe wire shapes for tools that
`codex-core` already knows how to execute.
Moving that remaining low-coupling layer into `codex-tools` keeps the
migration moving in meaningful chunks and trims another large block of
passive tool-spec construction out of `codex-core` without touching the
runtime-coupled handlers.
## What changed
- extended `codex-tools` to own the pure spec builders for:
- code-mode `exec` / `wait`
- `js_repl` / `js_repl_reset`
- MCP resource tools `list_mcp_resources`,
`list_mcp_resource_templates`, and `read_mcp_resource`
- utility tools `list_dir` and `test_sync_tool`
- split those builders across small module files with sibling
`*_tests.rs` coverage, keeping `src/lib.rs` exports-only
- rewired `core/src/tools/spec.rs` to call the extracted builders and
deleted the duplicated core-local implementations
- moved the direct JS REPL grammar seam test out of
`core/src/tools/spec_tests.rs` so it now lives with the extracted
implementation in `codex-tools`
- updated `codex-rs/tools/README.md` so the documented crate boundary
matches the new utility-spec surface
## Test plan
- `CARGO_TARGET_DIR=/tmp/codex-tools-utility-specs cargo test -p
codex-tools`
- `CARGO_TARGET_DIR=/tmp/codex-core-utility-specs cargo test -p
codex-core --lib tools::spec::`
- `just fix -p codex-tools -p codex-core`
- `just argument-comment-lint`
## References
- #15923
- #15928
- #15944
- #15953
- #16031
- #16047
- #16129
- #16132
- #16138
- #16141
## Why
The longer-term `codex-tools` migration is to move pure tool-definition
and tool-spec plumbing out of `codex-core` while leaving session- and
runtime-coupled orchestration behind.
The remaining code-mode adapter layer in
`core/src/tools/code_mode_description.rs` was a good next extraction
seam because it only transformed `ToolSpec` values for code mode and
already delegated the low-level description rendering to
`codex-code-mode`.
## What Changed
- added `codex-rs/tools/src/code_mode.rs` with
`augment_tool_spec_for_code_mode()` and
`tool_spec_to_code_mode_tool_definition()`
- added focused unit coverage in `codex-rs/tools/src/code_mode_tests.rs`
- rewired `core/src/tools/spec.rs` and `core/src/tools/code_mode/mod.rs`
to use the extracted adapters from `codex-tools`
- removed the old `core/src/tools/code_mode_description.rs` shim and its
test file from `codex-core`
- added the `codex-code-mode` dependency to `codex-tools`, updated
`Cargo.lock`, and refreshed the `codex-tools` README to reflect the
expanded boundary
## Test Plan
- `cargo test -p codex-tools`
- `CARGO_TARGET_DIR=/tmp/codex-core-code-mode-adapters cargo test -p
codex-core --lib tools::spec::`
- `CARGO_TARGET_DIR=/tmp/codex-core-code-mode-adapters cargo test -p
codex-core --lib tools::code_mode::`
- `just bazel-lock-update`
- `just bazel-lock-check`
- `just argument-comment-lint`
## References
- #15923
- #15928
- #15944
- #15953
- #16031
- #16047
- #16129
