## Why
Some MCP OAuth providers require a pre-registered public client ID and
cannot rely on dynamic client registration. Codex already supports MCP
OAuth, but it had no way to supply that client ID from config into the
PKCE flow.
## What changed
- add `oauth.client_id` under `[mcp_servers.<server>]` config, including
config editing and schema generation
- thread the configured client ID through CLI, app-server, plugin login,
and MCP skill dependency OAuth entrypoints
- configure RMCP authorization with the explicit client when present,
while preserving the existing dynamic-registration path when it is
absent
- add focused coverage for config parsing/serialization and OAuth URL
generation
## Verification
- `cargo test -p codex-config -p codex-rmcp-client -p codex-mcp -p
codex-core-plugins`
- `cargo test -p codex-core blocking_replace_mcp_servers_round_trips
--lib`
- `cargo test -p codex-core
replace_mcp_servers_streamable_http_serializes_oauth_resource --lib`
- `cargo test -p codex-core config_schema_matches_fixture --lib`
## Notes
Broader local package runs still hit unrelated pre-existing stack
overflows in:
- `codex-app-server::in_process_start_clamps_zero_channel_capacity`
-
`codex-core::resume_agent_from_rollout_uses_edge_data_when_descendant_metadata_source_is_stale`
## Why
`PreToolUse` already exposes `updatedInput` in its hook output schema,
but Codex currently rejects it instead of applying the rewrite. That
leaves hook authors unable to make the documented pre-execution
adjustment to a tool call before it runs.
## What
- Accept `updatedInput` from `PreToolUse` hooks when paired with
`permissionDecision: "allow"`.
- Apply the rewritten input before dispatch so the tool executes the
updated payload, not the original one.
- Preserve the stable hook-facing compatibility shapes that
participating tool handlers expose:
- Bash-like tools (`shell`, `container.exec`, `local_shell`,
`shell_command`, `exec_command`) use `{ "command": ... }`.
- `apply_patch` exposes its patch body through the same command-shaped
hook contract.
- MCP tools expose their JSON argument object directly.
- Keep each participating tool handler responsible for translating
hook-facing `updatedInput` back into its concrete invocation shape.
## Verification
Direct Bash-like rewrite coverage:
- `pre_tool_use_rewrites_shell_before_execution`
- `pre_tool_use_rewrites_container_exec_before_execution`
- `pre_tool_use_rewrites_local_shell_before_execution`
- `pre_tool_use_rewrites_shell_command_before_execution`
- `pre_tool_use_rewrites_exec_command_before_execution`
These cases assert that each supported Bash-like surface runs only the
rewritten command while the hook still observes the original `{
"command": ... }` input.
`pre_tool_use_rewrites_apply_patch_before_execution`
- Model emits one patch.
- Hook swaps in a different patch.
- Asserts only the rewritten file is created, and the hook saw the
original patch.
`pre_tool_use_rewrites_code_mode_nested_exec_command_before_execution`
- Model runs one nested shell command from code mode.
- Hook rewrites it.
- Asserts only the rewritten command runs, and the hook saw the original
nested input.
`pre_tool_use_rewrites_mcp_tool_before_execution`
- Model calls the RMCP echo tool.
- Hook rewrites the MCP arguments.
- Asserts the MCP server receives and returns the rewritten message, not
the original one.
# Why
We want shared hook trust that both the app and the TUI can build on,
but the metadata is only useful if runtime behavior agrees with it. This
PR adds a single backend trust model for hooks so unmanaged hooks cannot
run until the current definition has been reviewed, while managed hooks
remain runnable and non-configurable.
# What
- persist `trusted_hash` alongside hook state in `config.toml`
- expose `currentHash` and derived `trustStatus` through `hooks/list`
- derive trust from normalized hook definitions so equivalent hooks from
`config.toml` and `hooks.json` share the same trust identity
- gate unmanaged hooks on trust before they enter the runnable handler
set
# Reviewer Notes
- key file to review is `codex-rs/hooks/src/engine/discovery.rs`
- the only **core** change is schema related
## Summary
Lifecycle hooks currently treat `PreToolUse`, `PostToolUse`, and
`PermissionRequest` as Bash-only flows
- hook schema constrains `tool_name` to `Bash`
- hook input assumes a command-shaped `tool_input`
- core hook dispatch path passes only shell command strings
That means hooks cannot target MCP tools even though MCP tool names are
model-visible and stable
This change generalizes those hook paths so they can match and receive
payloads for MCP tools while preserving the existing Bash behavior.
## Reviewer Notes
I think these are the key files
- `codex-rs/core/src/tools/handlers/mcp.rs`
- `codex-rs/core/src/mcp_tool_call.rs`
Otherwise the changes across apply_patch, shell, and unified_exec are
mainly to rewire everything to be `tool_input` based instead of just
`command` so that it'll make sense for MCP tools.
## Changes
- Allow `PreToolUse`, `PostToolUse`, and `PermissionRequest` hook inputs
to carry arbitrary `tool_name` and `tool_input` values instead of
hard-coding `Bash` and command-only payloads.
- Add MCP hook payload support through `McpHandler`, using the
model-visible tool name from `ToolInvocation` and the raw MCP arguments
as `tool_input`.
- Include MCP tool responses in `PostToolUse` by serializing
`McpToolOutput` into the hook response payload.
- Run `PermissionRequest` hooks for MCP approval requests after
remembered approval checks and before falling back to user-facing MCP
elicitation.
- Preserve exact matching for literal hook matchers like `Bash` and
`mcp__memory__create_entities`, while keeping regex matcher support for
patterns like `mcp__memory__.*` and `mcp__.*__write.*`.
---------
Co-authored-by: Andrei Eternal <eternal@openai.com>
Co-authored-by: Codex <noreply@openai.com>
Matthew Zeng ·
Abhinav ·