## Summary
- make `CODEX_EXEC_SERVER_URL=none` map to an explicit disabled
environment mode instead of inferring from a missing URL
- expose environment capabilities (`exec_enabled`, `filesystem_enabled`)
so tool building can gate behavior explicitly and future
multi-environment work has a clearer seam
- suppress env-backed tools when the relevant capability is unavailable,
including exec tools, `js_repl`, `apply_patch`, `list_dir`, and
`view_image`
- keep handler/runtime backstops so disabled environments still reject
execution if a tool path somehow bypasses registration
## Testing
- `just fmt`
- `cargo test -p codex-exec-server`
- `cargo test -p codex-tools
disabled_environment_omits_environment_backed_tools`
- `cargo test -p codex-tools
environment_capabilities_gate_exec_and_filesystem_tools_independently`
- remote devbox Bazel build via `codex-applied-devbox`:
`//codex-rs/cli:cli`
## Why
#16513 moved pure tool-registry planning into `codex-tools`, but much of
the corresponding spec/feature-gating coverage still lived in
`codex-core`. That leaves the tests for planner behavior in the crate
that no longer owns that logic and makes the next extraction steps
harder to review.
## What
Move the planner-only `spec_tests.rs` coverage into
`codex-rs/tools/src/tool_registry_plan_tests.rs` and wire it up from
`codex-rs/tools/src/tool_registry_plan.rs` using the crate-local `#[path
= "tool_registry_plan_tests.rs"] mod tests;` pattern.
The `codex-core` test file now keeps the core-side integration checks:
router-visible model tool lists, namespaced handler alias registration,
shell adapter behavior, and MCP schema edge cases that still exercise
the `core` binding layer.
## Verification
- `cargo test -p codex-tools`
- `cargo test -p codex-core tools::spec::tests`
starr-openai