22 Commits

• Add selected-plugin precedence and attribution to the MCP catalog (#27884)

  ## Why
  
  **In short:** this PR resolves already-discovered MCP registrations. It
  does not read selected plugins or discover their MCP servers.
  
  The resolved MCP catalog currently builds config and auto-discovered
  plugin registrations before runtime contributors are applied. A
  thread-selected plugin needs a distinct precedence tier in that same
  initial resolution pass: otherwise a disabled lower-precedence winner
  can leave stale name-level state behind, and the winning MCP tools
  cannot be attributed to the selected package reliably.
  
  This PR adds that catalog boundary before executor discovery is
  connected.
  
  ## What changed
  
  - Added an explicit selected-plugin registration tier between
  auto-discovered plugins and explicit config.
  - Collected selected-plugin contributions before the initial catalog
  build, while leaving compatibility and generic extension overlays in
  their existing runtime phase.
  - Retained the winning plugin ID and display name directly on
  plugin-owned catalog registrations.
  - Derived MCP tool provenance from the winning catalog entry instead of
  joining against local-only plugin summaries.
  - Retained the winning selected server's tool approval policy in the
  running connection manager, so a selected registration cannot inherit
  approval behavior from a losing local plugin.
  - Kept remembered approval session-scoped for selected plugins until
  there is an authority-aware persistence contract; Codex will not write
  approval back to an unrelated local plugin.
  - Preserved existing name-level disabled vetoes for discovered plugins
  and config, while keeping a selected package's own disabled registration
  scoped to that registration.
  - Preserved deterministic selection order and existing config,
  compatibility, and extension precedence.
  
  The resulting order is:
  
  ```text
  auto-discovered plugin
    < selected plugin
    < explicit config
    < compatibility registration
    < extension overlay
  ```
  
  ## Behavior and scope
  
  This is a catalog and provenance change only. No production host
  contributes selected-plugin MCP registrations yet, so existing local MCP
  behavior remains unchanged.
  
  The stacked follow-up, #27870, installs the executor plugin provider
  that produces these registrations. App-server activation remains a
  separate final step.
  
  ## Verification
  
  Focused tests cover precedence, deterministic selected-plugin conflicts,
  disabled-veto behavior across catalog phases, managed requirements
  before selected-plugin resolution, winning-server approval policy, and
  attribution when local and selected packages share an ID or server name.
  CI owns execution of the test suite.

  jif · 2026-06-15 11:10:51 +02:00
  c3a479620f
• feat: use encrypted local secrets for MCP OAuth (#27541)

  ## Summary
  
  - store MCP OAuth credentials in the configured auth credential backend
  - support encrypted-local OAuth storage, including legacy keyring
  migration
  - propagate the credential backend through MCP refresh, session, CLI,
  and app-server paths
  
  ## Stack
  
  1. #27504 — config and feature flag
  2. #27535 — auth-specific secret namespaces
  3. #27539 — encrypted CLI auth storage
  4. this PR — encrypted MCP OAuth storage
  
  This is a parallel review stack; the original #17931 remains unchanged.
  
  ## Tests
  
  - `just test -p codex-rmcp-client` (the transport round-trip test passed
  after building the required `codex` binary and retrying)
  - `just test -p codex-mcp`
  - `just test -p codex-app-server
  refresh_config_uses_latest_auth_keyring_backend`
  - `just test -p codex-core
  refresh_mcp_servers_is_deferred_until_next_turn`
  - `just test -p codex-cli mcp`
  - `just fix -p codex-rmcp-client -p codex-mcp -p codex-core -p codex-cli
  -p codex-app-server -p codex-protocol`
  - `just bazel-lock-check`

  Celia Chen · 2026-06-12 22:03:51 +00:00
  9915d34684
• Use latest-wins MCP manager replacement (#27259)

  ## Summary
  
  We originally addressed startup prewarming holding the read side of
  `RwLock<McpConnectionManager>` by snapshotting tool-list state. Review
  feedback identified the broader ownership problem: the outer
  synchronization should only publish or retrieve the current manager,
  while MCP operations rely on the manager's internal synchronization. A
  follow-up preserved operation retirement with a separate gate, but
  further review questioned whether that synchronization was actually
  required and whether we could support latest-wins replacement instead.
  
  This PR now stores the current MCP manager in `ArcSwap`. Each operation
  uses `load_full()` to obtain an owned `Arc<McpConnectionManager>`, then
  performs MCP I/O without retaining the publication mechanism. Refresh
  cancels obsolete startup work, constructs a replacement, and atomically
  publishes it. New operations see the latest manager, while operations
  that already loaded the previous manager retain a valid handle. Refresh
  happens at a turn boundary, so there should be no active user tool calls
  to drain.
  
  Git history supports dropping the outer `RwLock`. It was introduced in
  `03ffe4d595` on November 17, 2025 for non-blocking MCP startup: the
  session published an empty manager, startup initialized that same object
  while holding the write lock, and readers waited for initialization.
  `7cd2e84026` on February 19, 2026 removed that two-phase initialization
  in favor of constructing a fresh manager and swapping it in, explicitly
  noting that `Option` or `OnceCell` could replace the placeholder design.
  Hot reload later reused the existing lock to publish a replacement, but
  I found no indication that the lock was introduced to guarantee
  in-flight tool calls finish before refresh or shutdown.
  
  Terminal shutdown remains separate from refresh: it aborts startup
  prewarming and active tasks before shutting down the current manager, so
  tool calls may be interrupted and no model WebSocket work continues
  after shutdown. Focused regression coverage exercises pending tool-list
  cancellation, deferred refresh, and startup-prewarm shutdown.

  Charlie Marsh · 2026-06-10 08:33:21 -07:00
  41b4fabbb4
• [codex] Make MCP connection startup fallible (#27261)

  ## Why
  
  Required MCP server startup was enforced in `Session::new` after
  `McpConnectionManager` had already created the clients. That split let
  other manager construction paths bypass the same requirement and exposed
  manager internals solely so the session could validate them. Keeping
  required-server readiness in the constructor gives every caller one
  consistent startup contract.
  
  ## What changed
  
  - make `McpConnectionManager::new` return `anyhow::Result<Self>` and
  fail when an enabled, required server cannot initialize
  - pass the startup cancellation token into the constructor so
  required-server waits remain cancellable
  - propagate constructor failures through resource reads, connector
  discovery, and MCP status collection
  - preserve the active manager and cancellation token when a refreshed
  replacement fails
  - keep required-startup failure collection private and cover the
  constructor error contract directly
  
  ## Validation
  
  - updated the focused connection-manager test to assert the complete
  required-server startup error
  - local tests not run; relying on CI

  Ahmed Ibrahim · 2026-06-10 00:17:58 -07:00
  a7b6baecc6
• Expose MCP server info as part of server status (#24698)

  # Summary
  
  Expose MCP server info via App Server (when available) so apps can
  render a richer MCP experience

  Gabriel Peal · 2026-05-28 09:38:34 -07:00
  8a827d6426
• Update rmcp to 1.7.0 (#24763)

  WIll make it easier to uprev when the new draft spec is supported.
  
  Also updates reqwest where needed for compatibility but doesn't update
  it everywhere since this is already a large diff.
  
  The new version of rmcp handles certain kinds of authentication failures
  differently, this patch includes support for identifying the failing scope
  in a WWW-Authenticate header.

  Adam Perry @ OpenAI · 2026-05-27 14:52:06 -07:00
  910578792f
• Remove reserved namespaces dedup (#24609)

  Avoid suffixing reserved namespaces.

  pakrym-oai · 2026-05-26 09:57:05 -07:00
  6937e8354a
• Move MCP tool naming mode into manager (#21576)

  ## 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`

  pakrym-oai · 2026-05-26 08:21:15 -07:00
  ff7513cd83
• Route MCP servers through explicit environments (#23583)

  ## Summary
  - route each configured MCP server through an explicit per-server
  `environment_id` instead of a manager-wide remote toggle
  - default omitted `environment_id` to `local`, resolve named ids through
  `EnvironmentManager`, and fail only the affected MCP server when an
  explicit id is unknown
  - keep local stdio on the existing local launcher path for now, while
  named-environment stdio uses the selected environment backend and
  requires an absolute `cwd`
  - allow local HTTP MCP servers to keep using the ambient HTTP client
  when no local `Environment` is configured; named-environment HTTP MCPs
  use that environment's HTTP client
  
  ## Validation
  - devbox Bazel build: `bazel build --bes_backend= --bes_results_url=
  //codex-rs/cli:codex //codex-rs/rmcp-client:test_stdio_server
  //codex-rs/rmcp-client:test_streamable_http_server`
  - devbox app-server config matrix with real `config.toml` /
  `environments.toml` files covering omitted local, explicit local,
  omitted local under remote default, explicit remote stdio, local HTTP
  without local env, explicit remote HTTP, local stdio without local env,
  unknown explicit env, and remote stdio without `cwd`

  starr-openai · 2026-05-21 17:19:54 +02:00
  298e5cfce1
• Make local environment optional in EnvironmentManager (#23369)

  ## Summary
  - make `EnvironmentManager` local environment/runtime paths optional
  - simplify constructor surface around snapshot materialization
  - rename local env accessors to `require_local_environment` /
  `try_local_environment`
  
  ## Validation
  - devbox Bazel build for touched crate surfaces
  - `//codex-rs/exec-server:exec-server-unit-tests`
  - `//codex-rs/app-server-client:app-server-client-unit-tests`
  - filtered touched `//codex-rs/core:core-unit-tests` cases

  starr-openai · 2026-05-19 12:55:34 -07:00
  5c43a64e2b
• Support explicit MCP OAuth client IDs (#22575)

  ## 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`

  Matthew Zeng · 2026-05-14 11:52:43 -07:00
  d8ddeb6869
• Remove connector_openai prefix filtering (#22555)

  Remove unnecessary prefix filtering from codex
  
  ## Test Plan
  
  Test local cli build + make sure backend returns appropriate apps 
  
  ```
  cd ~/code/codex/codex-rs
  cargo build -p codex-cli --bin codex
  ./target/debug/codex
  ```
  
  Appropriate apps show up in my list

  Eric Ning · 2026-05-13 16:59:22 -07:00
  64d8f387f9
• Simplify MCP tool handler plumbing (#21595)

  ## Why
  The MCP tool path had accumulated a few core-owned special cases: a
  dedicated payload variant, resolver plumbing, a legacy `AfterToolUse`
  translation path, and a side channel for parallel-call metadata. That
  made `ToolRegistry` and the spec builder know more about MCP than they
  needed to.
  
  This change moves MCP-specific execution details back onto `ToolInfo`
  and `McpHandler` so `codex-core` can treat MCP calls like normal
  function calls while still preserving MCP-specific dispatch and
  telemetry behavior where it belongs.
  
  ## What changed
  - removed `resolve_mcp_tool_info`, `ToolPayload::Mcp`, `ToolKind`, and
  the remaining registry-side MCP resolver path
  - stored MCP routing metadata directly on `McpHandler` and `ToolInfo`,
  including `supports_parallel_tool_calls`
  - deleted the legacy `AfterToolUse` consumer in `core`, which removes
  the need for handler-specific `after_tool_use_payload` implementations
  - switched tool-result telemetry to handler-provided tags and kept
  MCP-specific dispatch payload construction inside the handler
  - simplified tool spec planning/building by passing `ToolInfo` directly
  and dropping the direct/deferred MCP wrapper structs and the
  parallel-server side table
  
  ## Testing
  - `cargo check -p codex-core -p codex-mcp -p codex-otel`
  - `cargo test -p codex-core
  mcp_parallel_support_uses_exact_payload_server`
  - `cargo test -p codex-core
  direct_mcp_tools_register_namespaced_handlers`
  - `cargo test -p codex-core
  search_tool_description_lists_each_mcp_source_once`
  - `cargo test -p codex-mcp
  list_all_tools_uses_startup_snapshot_while_client_is_pending`
  - `just fix -p codex-core -p codex-mcp -p codex-otel`

  pakrym-oai · 2026-05-12 00:11:31 +00:00
  ed5944ba1d
• [elicitation] Advertise new url elicitation capability when auth_elicitation is enabled. (#22188)

  ## Why
  
  We've added support for auth elicitation behind the auth_elicitation
  flag, but servers need to explicitly check the capability before it
  decides to send elicitations in order to be backward compatible. This PR
  adds the capability advertising conditioned on the flag.
  
  ## What changed
  
  - Build `client_elicitation_capability` from the `AuthElicitation`
  feature state.
  - Thread that capability through MCP config, session startup, and
  `McpConnectionManager` so RMCP initialization advertises the correct
  elicitation support.
  - Advertise both `form` and `url` elicitation when the feature is
  enabled, and preserve the empty default capability when it is disabled.
  - Add coverage for the feature-derived config shape and the advertised
  initialization payload.
  
  ## Testing
  
  - `cargo test -p codex-mcp`
  - `cargo test -p codex-core
  to_mcp_config_preserves_auth_elicitation_feature_from_config`
  - `cargo test -p codex-core` *(currently fails outside this change in
  `tools::handlers::multi_agents::tests::tool_handlers_cascade_close_and_resume_and_keep_explicitly_closed_subtrees_closed`
  with a stack overflow after unrelated tests have started running)*

  Matthew Zeng · 2026-05-11 12:23:55 -07:00
  192481d1a1
• Remove ToolName display helper (#21465)

  ## Why
  
  `ToolName::display()` made it too easy to flatten tool identity and
  accidentally compare rendered strings. Tool identity should stay
  structural until a legacy string boundary actually requires the
  flattened spelling.
  
  ## What
  
  - Removes `ToolName::display()` and relies on the existing `Display`
  impl for messages and errors.
  - Adds structural ordering for `ToolName` and uses it for
  sorting/deduping deferred tools.
  - Carries `ToolName` through tool/sandbox plumbing, flattening only at
  legacy boundaries such as hook payloads, telemetry tags, and Responses
  tool names.
  - Updates MCP normalization tests to assert `ToolName` structure instead
  of rendered strings.
  
  ## Testing
  
  - `cargo test -p codex-mcp test_normalize_tools`
  - `cargo test -p codex-core unavailable_tool`
  - `just fix -p codex-protocol`
  - `just fix -p codex-mcp`
  - `just fix -p codex-core`

  pakrym-oai · 2026-05-08 12:17:48 -07:00
  61142b6169
• [codex] Remove string-keyed MCP tool maps (#21454)

  ## 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`

  pakrym-oai · 2026-05-07 10:16:10 -07:00
  857e731478
• feat: make built-in MCPs first-class runtime servers (#21356)

  ## DISCLAIMER
  This is experimental and no production service must rely on this
  
  ## Why
  
  Built-in MCPs are product-owned runtime capabilities, but they were
  previously flattened into the same config-backed stdio path as
  user-configured servers. That made them depend on a hidden `codex
  builtin-mcp` re-exec path, exposed them through config-oriented CLI
  flows, and erased distinctions the runtime needs to preserve—most
  notably whether an MCP call should count as external context for
  memory-mode pollution.
  
  ## What changed
  
  - Model product-owned built-ins separately from config-backed MCP
  servers via `BuiltinMcpServer` and `EffectiveMcpServer`.
  - Launch built-ins in process through a reusable async transport instead
  of the hidden `builtin-mcp` stdio subcommand.
  - Keep config-oriented CLI operations such as `codex mcp
  list/get/login/logout` scoped to configured servers, while merging
  built-ins only into the effective runtime server set.
  - Retain server metadata after launch so parallel-tool support and
  context classification come from the live server set; built-in
  `memories` is now classified as local Codex state rather than external
  context.
  
  ## Test plan
  
  - `cargo test -p codex-mcp`
  - `cargo test -p codex-core --test suite
  builtin_memories_mcp_call_does_not_mark_thread_memory_mode_polluted_when_configured`
  
  ---------
  
  Co-authored-by: Codex <noreply@openai.com>

  jif-oai · 2026-05-07 10:36:32 +02:00
  b2268999fe
• Route opted-in MCP elicitations through Guardian (#19431)

  # Motivation
  
  Browser Use origin-access prompts are MCP elicitations, not direct
  tool-call approval prompts, so they were bypassing the Guardian approval
  path. We need a generic opt-in that lets eligible MCP elicitations use
  Guardian when the current turn already routes approvals there.
  
  # Description
  
  Add a generic elicitation reviewer hook in codex-mcp and wire codex-core
  to pass a Guardian reviewer callback when creating the MCP connection
  manager. The reviewer validates explicit mcp_tool_call opt-in metadata,
  builds a Guardian MCP tool-call review request from
  server/tool/connector metadata and tool params, and maps Guardian
  approval, denial, timeout, and cancellation decisions back to MCP
  elicitation responses.
  
  The new option to trigger this in the `_meta` object is:
  ```
  "codex_request_type": "approval_request",
  ```
  
  # Testing
  
  - RUST_MIN_STACK=8388608 NEXTEST_STATUS_LEVEL=leak cargo nextest run
  --no-fail-fast --cargo-profile ci-test --test-threads 2
  - cargo clippy --tests -- -D warnings
  - cargo fmt -- --config imports_granularity=Item --check
  - cargo shear
  - pnpm run format
  - python3 .github/scripts/verify_cargo_workspace_manifests.py
  - python3 .github/scripts/verify_tui_core_boundary.py
  - python3 .github/scripts/verify_bazel_clippy_lints.py
  - git diff --check

  Clark DuVall · 2026-05-06 19:42:45 +00:00
  346070a424
• Use MCP server instructions in deferred namespace descriptions (#21053)

  ## Why
  
  MCP servers can provide `instructions` that explain what their tools are
  for. Directly exposed MCP namespaces already use those instructions when
  a connector description is not available, but deferred `tool_search`
  results did not preserve that fallback. The direct path falls back from
  connector metadata to server instructions, while the deferred path only
  carried `connector_description` and otherwise fell back to generic
  namespace text.
  
  That meant a plain MCP server could provide useful model-facing guidance
  and still appear as `Tools in the X namespace.` whenever it was
  discovered lazily through `tool_search`.
  
  ## What changed
  
  - Store one model-facing `namespace_description` on `ToolInfo`, using
  connector descriptions for connector-backed tools and server
  instructions for plain MCP servers.
  - Thread that namespace description through the `tool_search` source
  list, search indexing, and returned namespace metadata.
  - Add an end-to-end regression test for deferred non-app MCP search
  results exposing server instructions as the namespace description.
  
  ## Verification
  
  - `cargo test -p codex-tools
  search_tool_description_lists_each_mcp_source_once --lib`
  - `cargo test -p codex-core --test all
  tool_search_uses_non_app_mcp_server_instructions_as_namespace_description`

  sayan-oai · 2026-05-04 19:36:07 +00:00
  b9e8df47da
• Use the 2025-06-18 elicitation capability shape (#20562)

  # Why
  
  Codex currently negotiates MCP `2025-06-18`, where the client
  elicitation capability is represented as an empty object. We were still
  serializing `capabilities.elicitation.form`, which belongs to the later
  capability shape and can cause strict `2025-06-18` servers to reject
  `initialize` with an unrecognized-field error.
  
  This keeps the handshake aligned with the protocol version Codex
  actually negotiates and fixes the compatibility regression tracked in
  #17492.
  
  # What
  
  - Serialize the client elicitation capability as `elicitation: {}` for
  `2025-06-18`.
  - Keep elicitation advertised for both Codex Apps and custom MCP
  servers.
  - Tighten regression coverage so the unit test asserts both the Rust
  value and the serialized wire shape.
  - Add an app-server integration test that round-trips a form elicitation
  from a custom MCP server; the existing connector round-trip continues to
  cover the connector path.
  
  # Verification
  
  - `cargo test -p codex-mcp`
  - `cargo test -p codex-app-server mcp_server_elicitation_round_trip`
  - `cargo test -p codex-app-server
  mcp_server_tool_call_round_trips_elicitation`
  
  # Next steps
  
  - Decide whether `tool_call_mcp_elicitation=false` should also suppress
  capability advertisement during `initialize`.
  - Revisit `form` / `url` capability advertisement when Codex is ready to
  negotiate MCP `2025-11-25`, which defines that newer shape.

  Abhinav · 2026-05-01 14:16:22 -07:00
  443f6b831e
• Terminate stdio MCP servers on shutdown to avoid process leaks (#19753)

  ## Why
  
  Several bug reports describe thread shutdown (including subagent
  threads) leaving stdio MCP server processes behind. These reports all
  point at the same lifecycle gap: Codex launches stdio MCP servers, but
  the session-level shutdown path does not explicitly close MCP clients or
  terminate the server process tree.
  
  Fixes #12491
  Fixes #12976
  Fixes #18881
  Fixes #19469
  
  ## History
  
  This is best understood as a regression/coverage gap in MCP session
  lifecycle management, not as stdio MCP cleanup being absent all along.
  #10710 added process-group cleanup for stdio MCP servers, but that
  cleanup only runs when the `RmcpClient`/transport is dropped. The older
  reports (#12491 and #12976) came after that cleanup existed, which
  suggests the remaining problem was that some higher-level shutdown paths
  kept the MCP manager alive or replaced it without explicitly draining
  clients. The newer reports (#18881 and #19469) exposed the same family
  around manager replacement and shutdown.
  
  ## What changed
  
  - Added an explicit stdio MCP process handle in `codex-rmcp-client` so
  local MCP servers terminate their process group and executor-backed MCP
  servers call the executor process terminator.
  - Added `RmcpClient::shutdown()` and manager-level MCP shutdown draining
  so session shutdown, channel-close fallback, MCP refresh, and connector
  probing stop owned MCP clients.
  - Added regression coverage that starts a stdio MCP server, begins an
  in-flight blocking tool call, shuts down the client, and asserts the
  server process exits.
  
  ## Verification
  
  - `cargo test -p codex-rmcp-client`
  - `cargo test -p codex-mcp`
  - `just fix -p codex-rmcp-client`
  - `just fix -p codex-mcp`
  - `just fix -p codex-core`
  
  - Manual before/after validation with a temporary repro script:
  - Pre-fix binary from `HEAD^` (`fed0a8f4fa`): reproduced the leak with
  surviving MCP server and child PIDs, `survivors=[77583, 77592]`,
  `leaked=true`.
  - Post-fix binary from this branch (`67e318148b`): verified both MCP
  processes were gone after interrupting `codex exec`, `survivors=[]`,
  `leaked=false`.

  Eric Traut · 2026-04-28 09:29:57 -07:00
  4e0cf945b7
• Split MCP connection modules (#19725)

  ## Why
  
  The MCP connection manager module had grown to mix orchestration, RMCP
  client startup, elicitation handling, Codex Apps cache and naming
  behavior, tool qualification and filtering, and runtime data. The
  previous stacked PRs split these responsibilities incrementally; this PR
  collapses that work into one self-contained refactor on latest main.
  
  ## What changed
  
  - Move McpConnectionManager into connection_manager.rs.
  - Move RMCP client lifecycle, startup, and uncached tool listing into
  rmcp_client.rs.
  - Move elicitation request tracking and policy handling into
  elicitation.rs.
  - Move Codex Apps cache, key, filtering, and naming helpers into
  codex_apps.rs.
  - Rename the tool-name helper module to tools.rs and move ToolInfo, tool
  filtering, schema masking, and qualification there.
  - Move runtime and sandbox shared types into runtime.rs.
  - Preserve latest main PermissionProfile-based MCP elicitation
  auto-approval behavior.
  
  ## Verification
  
  - just fmt
  - cargo check -p codex-mcp
  - cargo check -p codex-mcp --tests
  - cargo check -p codex-core
  
  ---------
  
  Co-authored-by: Codex <noreply@openai.com>

  Ahmed Ibrahim · 2026-04-26 23:23:34 +00:00
  0bda8161a2