## Why
`skills/list` is already exposed through app-server v2 and covered by
the app-server test suite. Keeping the separate core `Op::ListSkills`
path leaves a duplicate legacy protocol surface that no longer needs to
be maintained.
## What Changed
- Removed `Op::ListSkills` and `EventMsg::ListSkillsResponse` from the
core protocol.
- Deleted the corresponding core session handler and stale core
integration tests.
- Removed rollout/MCP ignore branches and protocol v1 docs references
for the deleted event/op.
- Left app-server `skills/list` and its existing coverage intact.
## Validation
- `cargo test -p codex-protocol`
- `cargo test -p codex-core --test all suite::skills`
- `cargo check -p codex-mcp-server -p codex-rollout -p
codex-rollout-trace`
- `just fix -p codex-core`
## Why
Thread names are app-server metadata now, backed by the thread store and
sqlite state database. Keeping a core `SetThreadName` op plus a rollout
`thread_name_updated` event made rename persistence live in the wrong
layer and required historical replay support for an event that new
app-server flows should not write.
## What changed
- Removed `Op::SetThreadName` and `EventMsg::ThreadNameUpdated` from the
core protocol and deleted the core handler path that appended rename
events to rollouts.
- Updated app-server `thread/name/set` so both loaded and unloaded
threads write through thread-store metadata and app-server emits
`thread/name/updated` notifications.
- Updated local thread-store name metadata updates to write sqlite title
metadata and the legacy thread-name index without appending rollout
events.
- Removed state extraction and rollout handling for the deleted
thread-name event.
## Validation
- `cargo test -p codex-app-server thread_name_updated_broadcasts`
- `cargo test -p codex-app-server
thread_name_set_is_reflected_in_read_list_and_resume`
- `cargo test -p codex-thread-store
update_thread_metadata_sets_name_on_active_rollout_and_indexes_name`
- `cargo test -p codex-state`
- `cargo check -p codex-mcp-server -p codex-rollout-trace`
- `just fix -p codex-app-server -p codex-thread-store -p codex-state -p
codex-mcp-server -p codex-rollout-trace`
## Docs
No external documentation update is expected for this internal ownership
change.
## Why
Image-view results should be represented as a core-produced turn item
instead of being reconstructed by app-server. At the same time, existing
rollout/history paths still understand the legacy `ViewImageToolCall`
event, so this keeps that event as compatibility output generated from
the new item lifecycle.
## What changed
- Added `TurnItem::ImageView` to `codex-protocol`.
- Emitted image-view item start/completion directly from the core
`view_image` handler.
- Kept `ViewImageToolCall` as a legacy event and generate it from
completed `TurnItem::ImageView` items.
- Kept `thread_history.rs` on the legacy `ViewImageToolCall` replay
path, with `ImageView` item lifecycle events ignored there.
- Updated app-server protocol conversion, rollout persistence, and
affected exhaustive event matches for the new item plus legacy fan-out
shape.
## Verification
- `cargo test -p codex-protocol -p codex-app-server-protocol -p
codex-rollout -p codex-rollout-trace -p codex-mcp-server -p
codex-app-server --lib`
- `cargo test -p codex-core --test all
view_image_tool_attaches_local_image`
- `just fix -p codex-protocol -p codex-core -p codex-app-server-protocol
-p codex-app-server -p codex-rollout -p codex-rollout-trace -p
codex-mcp-server`
- `git diff --check`
## Why
Several legacy `EventMsg` variants were still emitted or mapped even
though clients either ignored them or had moved to item/lifecycle
events. `Op::Undo` had also degraded to an unavailable shim, so this
removes that dead task path instead of preserving a command that cannot
do useful work.
`McpStartupComplete`, `WebSearchBegin`, and `ImageGenerationBegin` are
intentionally kept because useful consumers still depend on them: MCP
startup completion drives readiness behavior, and the begin events let
app-server/core consumers surface in-progress web-search and
image-generation items before the final payload arrives.
## What Changed
- Removed weak legacy event variants and payloads from `codex-protocol`,
including legacy agent deltas, background events, and undo lifecycle
events.
- Kept/restored `EventMsg::McpStartupComplete`,
`EventMsg::WebSearchBegin`, and `EventMsg::ImageGenerationBegin` with
serializer and emission coverage.
- Updated core, rollout, MCP server, app-server thread history,
review/delegate filtering, and tests to rely on the useful replacement
events that remain.
- Removed `Op::Undo`, `UndoTask`, the undo test module, and stale TUI
slash-command comments.
- Stopped agent job/background progress and compaction retry notices
from emitting `BackgroundEvent` payloads.
## Verification
- `cargo check -p codex-protocol -p codex-app-server-protocol -p
codex-core -p codex-rollout -p codex-rollout-trace -p codex-mcp-server`
- `cargo test -p codex-protocol -p codex-app-server-protocol -p
codex-rollout -p codex-rollout-trace -p codex-mcp-server`
- `cargo test -p codex-core --test all suite::items`
- `just fix -p codex-protocol -p codex-app-server-protocol -p codex-core
-p codex-rollout -p codex-rollout-trace -p codex-mcp-server`
- Earlier coverage on this PR also included `codex-mcp`, `codex-tui`,
core library tests, MCP/plugin/delegate/review/agent job tests, and MCP
startup TUI tests.
Adds the app-server v2 goal API on top of the persisted goal state from
PR 1.
## Why
Clients need a stable app-server surface for reading and controlling
materialized thread goals before the model tools and TUI can use them.
Goal changes also need to be observable by app-server clients, including
clients that resume an existing thread.
## What changed
- Added v2 `thread/goal/get`, `thread/goal/set`, and `thread/goal/clear`
RPCs for materialized threads.
- Added `thread/goal/updated` and `thread/goal/cleared` notifications so
clients can keep local goal state in sync.
- Added resume/snapshot wiring so reconnecting clients see the current
goal state for a thread.
- Added app-server handlers that reconcile persisted rollout state
before direct goal mutations.
- Updated the app-server README plus generated JSON and TypeScript
schema fixtures for the new API surface.
## Verification
- Added app-server v2 coverage for goal get/set/clear behavior,
notification emission, resume snapshots, and non-local thread-store
interactions.
## Summary
Adds the debug CLI entry point for reducing recorded rollout traces.
This gives developers a direct way to inspect whether the emitted trace
stream reduces into the expected conversation/runtime model.
## Stack
This is PR 5/5 in the rollout trace stack.
- [#18876](https://github.com/openai/codex/pull/18876): Add rollout
trace crate
- [#18877](https://github.com/openai/codex/pull/18877): Record core
session rollout traces
- [#18878](https://github.com/openai/codex/pull/18878): Trace tool and
code-mode boundaries
- [#18879](https://github.com/openai/codex/pull/18879): Trace sessions
and multi-agent edges
- [#18880](https://github.com/openai/codex/pull/18880): Add debug trace
reduction command
## Review Notes
This PR is intentionally last: it depends on the trace crate, core
recorder, runtime/tool events, and session/agent edge data all existing.
The command should remain a debug/developer tool and avoid adding new
runtime behavior.
The useful review question is whether the CLI exposes the reducer in the
smallest practical way for local inspection without turning the debug
command into a supported user-facing workflow.