## Why
The `non_prefixed_mcp_tool_names` feature should be applied where MCP
tools become model-visible, not by remapping names later in core.
Keeping the decision in `McpConnectionManager` construction makes
`ToolInfo` the single shaped view that spec building, deferred tool
search, routing, and unavailable-tool placeholders can consume directly.
This also preserves the existing external behavior while the feature is
off, and keeps the feature-on behavior for code mode and hooks explicit
at the manager boundary.
## What Changed
- Add `McpToolNameMode` to `codex-mcp` and flow it through `McpConfig`
into `McpConnectionManager::new`.
- Normalize MCP `ToolInfo` names in the manager using either
legacy-prefixed namespaces or non-prefixed namespaces; the legacy path
adds `mcp__` without restoring the old trailing namespace suffix.
- Remove the core-side MCP name remapping path so specs, tool search,
session resolution, and unavailable-tool placeholder construction use
the manager-provided `ToolName` values directly.
- Keep code mode flattening on the `__` namespace separator.
- Preserve hook compatibility by giving non-prefixed MCP hook names
legacy `mcp__...` matcher aliases.
- Add/adjust integration and unit coverage for non-prefixed code-mode
behavior, hook matching with the feature on and off, and manager-level
legacy prefixing.
## Testing
- `cargo test -p codex-mcp --lib`
- `cargo test -p codex-core --lib tools::spec::tests -- --nocapture`
- `cargo test -p codex-core --lib mcp_tools -- --nocapture`
- `cargo test -p codex-core --lib mcp_tool_exposure -- --nocapture`
- `cargo test -p codex-core --test all mcp_tool -- --nocapture`
- `cargo test -p codex-core --test all search_tool -- --nocapture`
- `cargo test -p codex-core --test all hooks_mcp -- --nocapture`
- `cargo test -p codex-core --test all
code_mode_uses_non_prefixed_mcp_tool_names_when_feature_enabled --
--nocapture`
- `cargo test -p codex-tools`
- `cargo test -p codex-features`
## Summary
This PR removes the synthetic `HashMap<String, ToolInfo>` keys from MCP
tool discovery. `McpConnectionManager::list_all_tools()` now returns
normalized `Vec<ToolInfo>`, and downstream code derives identity from
`ToolInfo::canonical_tool_name()`.
The motivation is to keep model-visible tool identity on
`ToolName`/`ToolInfo` instead of parallel string map keys, so future
namespace changes do not have to preserve otherwise-unused lookup keys.
## Changes
- Rename the MCP normalization path from `qualify_tools` to
`normalize_tools_for_model` and return tool values directly.
- Flow MCP tool lists through connectors, plugin injection, router/spec
building, code mode, and tool search as vectors/slices.
- Keep direct/deferred subtraction local to `mcp_tool_exposure`, using
`ToolName` values.
- Update tests to compare `ToolName` instances where MCP identity
matters.
## Validation
- `cargo test -p codex-mcp test_normalize_tools`
- `cargo test -p codex-core mcp_tool_exposure`
- `cargo test -p codex-core
direct_mcp_tools_register_namespaced_handlers`
- `cargo test -p codex-core
search_tool_registers_namespaced_mcp_tool_aliases`
- `just fix -p codex-mcp`
- `just fix -p codex-core`
