## Summary
- add a regression test for
`InterAgentCommunication::to_response_input_item`
- assert replayed inter-agent messages keep `phase:
Some(MessagePhase::Commentary)`
## Test plan
- `cargo test -p codex-protocol`
- `just argument-comment-lint`
## Summary
When a `spawn_agent` call does a full-history fork, keep the parent's
effective agent type and model configuration instead of applying child
role/model overrides.
This is the minimal config-inheritance slice of #16055. Prompt-cache key
inheritance and MCP tool-surface stability are split into follow-up PRs.
## Design
- Reject `agent_type`, `model`, and `reasoning_effort` for v1
`fork_context` spawns.
- Reject `agent_type`, `model`, and `reasoning_effort` for v2
`fork_turns = "all"` spawns.
- Keep v2 partial-history forks (`fork_turns = "N"`) configurable;
requested model/reasoning overrides and role config still apply there.
- Keep non-forked spawn behavior unchanged.
## Tests
- `cargo +1.93.1 test -p codex-core spawn_agent_fork_context --lib`
- `cargo +1.93.1 test -p codex-core multi_agent_v2_spawn_fork_turns
--lib`
- `cargo +1.93.1 test -p codex-core
multi_agent_v2_spawn_partial_fork_turns_allows_agent_type_override
--lib`
### Motivation
- Interrupting a running turn (Ctrl+C / Esc) currently also terminates
long‑running background shells, which is surprising for workflows like
local dev servers or file watchers.
- The existing cleanup command name was confusing; callers expect an
explicit command to stop background terminals rather than a UI clear
action.
- Make background‑shell termination explicit and surface a clearer
command name while preserving backward compatibility.
### Description
- Renamed the background‑terminal cleanup slash command from `Clean`
(`/clean`) to `Stop` (`/stop`) and kept `clean` as an alias in the
command parsing/visibility layer, updated the user descriptions and
command popup wiring accordingly.
- Updated the unified‑exec footer text and snapshots to point to `/stop`
(and trimmed corresponding snapshot output to match the new label).
- Changed interrupt behavior so `Op::Interrupt` (Ctrl+C / Esc interrupt)
no longer closes or clears tracked unified exec / background terminal
processes in the TUI or core cleanup path; background shells are now
preserved after an interrupt.
- Updated protocol/docs to clarify that `turn/interrupt` (or
`Op::Interrupt`) interrupts the active turn but does not terminate
background terminals, and that `thread/backgroundTerminals/clean` is the
explicit API to stop those shells.
- Updated unit/integration tests and insta snapshots in the TUI and core
unified‑exec suites to reflect the new semantics and command name.
### Testing
- Ran formatting with `just fmt` in `codex-rs` (succeeded).
- Ran `cargo test -p codex-protocol` (succeeded).
- Attempted `cargo test -p codex-tui` but the build could not complete
in this environment due to a native build dependency that requires
`libcap` development headers (the `codex-linux-sandbox` vendored build
step); install `libcap-dev` / make `libcap.pc` available in
`PKG_CONFIG_PATH` to run the TUI test suite locally.
- Updated and accepted the affected `insta` snapshots for the TUI
changes so visual diffs reflect the new `/stop` wording and preserved
interrupt behavior.
------
[Codex
Task](https://chatgpt.com/codex/tasks/task_i_69b39c44b6dc8323bd133ae206310fae)
Backtracking multiple times could drop earlier turns. We now derive the
active user-turn positions from the transcript on demand (keying off the
latest session header) instead of caching state. This keeps the replayed
context intact during repeated edits and adds a regression test.
friel-openai