Move the general `Apps`, `Skills` and `Plugins` instructions blocks out
of `user_instructions` and into the developer message, with new `Apps ->
Skills -> Plugins` order for better clarity.
Also wrap those sections in stable XML-style instruction tags (like
other sections) and update prompt-layout tests/snapshots. This makes the
tests less brittle in snapshot output (we can parse the sections), and
it consolidates the capability instructions in one place.
#### Tests
Updated snapshots, added tests.
`<AGENTS_MD>` disappearing in snapshots is expected: before this change,
the wrapped user-instructions message was kept alive by `Skills`
content. Now that `Skills` and `Plugins` are in the developer message,
that wrapper only appears when there is real
project-doc/user-instructions content.
---------
Co-authored-by: Charley Cunningham <ccunningham@openai.com>
## Summary
- defer fresh-session `build_initial_context()` until the first real
turn instead of seeding model-visible context during startup
- rely on the existing `reference_context_item == None` turn-start path
to inject full initial context on that first real turn (and again after
baseline resets such as compaction)
- add a regression test for `InitialHistory::New` and update affected
deterministic tests / snapshots around developer-message layout,
collaboration instructions, personality updates, and compact request
shapes
## Notes
- this PR does not add any special empty-thread `/compact` behavior
- most of the snapshot churn is the direct result of moving the initial
model-visible context from startup to the first real turn, so first-turn
request layouts no longer contain a pre-user startup copy of permissions
/ environment / other developer-visible context
- remote manual `/compact` with no prior user still skips the remote
compact request; local first-turn `/compact` still issues a compact
request, but that request now reflects the lack of startup-seeded
context
---------
Co-authored-by: Codex <noreply@openai.com>
- Replay thread rollback from the persisted rollout history instead of
truncating in-memory state.\n- Add rollback coverage, including
rollback-behind-compaction snapshot coverage.
## Summary
- record a realtime close developer message when a new realtime session
replaces an active one
- assert the replacement marker through the mocked responses request
path
---------
Co-authored-by: Codex <noreply@openai.com>
Co-authored-by: Charles Cunningham <ccunningham@openai.com>
## Summary
- bundle contextual prompt injection into at most one developer message
plus one contextual user message in both:
- per-turn settings updates
- initial context insertion
- preserve `<model_switch>` across compaction by rebuilding it through
canonical initial-context injection, instead of relying on
strip/reattach hacks
- centralize contextual user fragment detection in one shared definition
table and reuse it for parsing/compaction logic
- keep `AGENTS.md` in its natural serialized format:
- `# AGENTS.md instructions for {dirname}`
- `<INSTRUCTIONS>...</INSTRUCTIONS>`
- simplify related tests/helpers and accept the expected snapshot/layout
updates from bundled multi-part messages
## Why
The goal is to converge toward a simpler, more intentional prompt shape
where contextual updates are consistently represented as one developer
envelope plus one contextual user envelope, while keeping parsing and
compaction behavior aligned with that representation.
## Notable details
- the temporary `SettingsUpdateEnvelope` wrapper was removed; these
paths now return `Vec<ResponseItem>` directly
- local/remote compaction no longer rely on model-switch strip/restore
helpers
- contextual user detection is now driven by shared fragment definitions
instead of ad hoc matcher assembly
- AGENTS/user instructions are still the same logical context; only the
synthetic `<user_instructions>` wrapper was replaced by the natural
AGENTS text format
## Testing
- `just fmt`
- `cargo test -p codex-app-server
codex_message_processor::tests::extract_conversation_summary_prefers_plain_user_messages
-- --exact`
- `cargo test -p codex-core
compact::tests::collect_user_messages_filters_session_prefix_entries
--lib -- --exact`
- `cargo test -p codex-core --test all
'suite::compact::snapshot_request_shape_pre_turn_compaction_strips_incoming_model_switch'
-- --exact`
- `cargo test -p codex-core --test all
'suite::compact_remote::snapshot_request_shape_remote_pre_turn_compaction_strips_incoming_model_switch'
-- --exact`
- `cargo test -p codex-core --test all
'suite::client::includes_apps_guidance_as_developer_message_when_enabled'
-- --exact`
- `cargo test -p codex-core --test all
'suite::client::includes_developer_instructions_message_in_request' --
--exact`
- `cargo test -p codex-core --test all
'suite::client::includes_user_instructions_message_in_request' --
--exact`
- `cargo test -p codex-core --test all
'suite::client::resume_includes_initial_messages_and_sends_prior_items'
-- --exact`
- `cargo test -p codex-core --test all
'suite::review::review_input_isolated_from_parent_history' -- --exact`
- `cargo test -p codex-exec --test all
'suite::resume::exec_resume_last_respects_cwd_filter_and_all_flag' --
--exact`
- `cargo test -p core_test_support
context_snapshot::tests::full_text_mode_preserves_unredacted_text --
--exact`
## Notes
- I also ran several targeted `compact`, `compact_remote`,
`prompt_caching`, `model_visible_layout`, and `event_mapping` tests
while iterating on prompt-shape changes.
- I have not claimed a clean full-workspace `cargo test` from this
environment because local sandbox/resource conditions have previously
produced unrelated failures in large workspace runs.
## Summary
- move regular-turn context diff/full-context persistence into
`run_turn` so pre-turn compaction runs before incoming context updates
are recorded
- after successful pre-turn compaction, rely on a cleared
`reference_context_item` to trigger full context reinjection on the
follow-up regular turn (manual `/compact` keeps replacement history
summary-only and also clears the baseline)
- preserve `<model_switch>` when full context is reinjected, and inject
it *before* the rest of the full-context items
- scope `reference_context_item` and `previous_model` to regular user
turns only so standalone tasks (`/compact`, shell, review, undo) cannot
suppress future reinjection or `<model_switch>` behavior
- make context-diff persistence + `reference_context_item` updates
explicit in the regular-turn path, with clearer docs/comments around the
invariant
- stop persisting local `/compact` `RolloutItem::TurnContext` snapshots
(only regular turns persist `TurnContextItem` now)
- simplify resume/fork previous-model/reference-baseline hydration by
looking up the last surviving turn context from rollout lifecycle
events, including rollback and compaction-crossing handling
- remove the legacy fallback that guessed from bare `TurnContext`
rollouts without lifecycle events
- update compaction/remote-compaction/model-visible snapshots and
compact test assertions (including remote compaction mock response
shape)
## Why
We were persisting incoming context items before spawning the regular
turn task, which let pre-turn compaction requests accidentally include
incoming context diffs without the new user message. Fixing that exposed
follow-on baseline issues around `/compact`, resume/fork, and standalone
tasks that could cause duplicate context injection or suppress
`<model_switch>` instructions.
This PR re-centers the invariants around regular turns:
- regular turns persist model-visible context diffs/full reinjection and
update the `reference_context_item`
- standalone tasks do not advance those regular-turn baselines
- compaction clears the baseline when replacement history may have
stripped the referenced context diffs
## Follow-ups (TODOs left in code)
- `TODO(ccunningham)`: fix rollback/backtracking baseline handling more
comprehensively
- `TODO(ccunningham)`: include pending incoming context items in
pre-turn compaction threshold estimation
- `TODO(ccunningham)`: inject updated personality spec alongside
`<model_switch>` so some model-switch paths can avoid forced full
reinjection
- `TODO(ccunningham)`: review task turn lifecycle
(`TurnStarted`/`TurnComplete`) behavior and emit task-start context
diffs for task types that should have them (excluding `/compact`)
## Validation
- `just fmt`
- CI should cover the updated compaction/resume/model-visible snapshot
expectations and rollout-hydration behavior
- I did **not** rerun the full local test suite after the latest
resume-lookup / rollout-persistence simplifications
## Summary
- add a dedicated `core/tests/suite/model_visible_layout.rs` snapshot
suite to materialize model-visible request layout in high-value
scenarios
- add three reviewer-focused snapshot scenarios:
- turn-level context updates (cwd / permissions / personality)
- first post-resume turn with model hydration + personality change
- first post-resume turn where pre-turn model override matches rollout
model
- wire the new suite into `core/tests/suite/mod.rs`
- commit generated `insta` snapshots under `core/tests/suite/snapshots/`
## Why
This creates a stable, reviewable baseline of model-visible context
layout against `main` before follow-on context-management refactors. It
lets subsequent PRs show focused snapshot diffs for behavior changes
instead of introducing the test surface and behavior changes at once.
## Testing
- `just fmt`
- `INSTA_UPDATE=always cargo test -p codex-core model_visible_layout`
## Summary
- standardize remote compaction test mocking around one default behavior
in shared helpers
- make default remote compact mocks mirror production shape: keep
`message/user` + `message/developer`, drop assistant/tool artifacts,
then append a summary user message
- switch non-special `compact_remote` tests to the shared default mock
instead of ad-hoc JSON payloads
## Special-case tests that still use explicit mocks
- remote compaction error payload / HTTP failure behavior
- summary-only compact output behavior
- manual `/compact` with no prior user messages
- stale developer-instruction injection coverage
## Why
This removes inconsistent manual remote compaction fixtures and gives us
one source of truth for normal remote compact behavior, while preserving
explicit mocks only where tests intentionally cover non-default
behavior.
This PR keeps compaction context-layout test coverage separate from
runtime compaction behavior changes, so runtime logic review can stay
focused.
## Included
- Adds reusable context snapshot helpers in
`core/tests/common/context_snapshot.rs` for rendering model-visible
request/history shapes.
- Standardizes helper naming for readability:
- `format_request_input_snapshot`
- `format_response_items_snapshot`
- `format_labeled_requests_snapshot`
- `format_labeled_items_snapshot`
- Expands snapshot coverage for both local and remote compaction flows:
- pre-turn auto-compaction
- pre-turn failure/context-window-exceeded paths
- mid-turn continuation compaction
- manual `/compact` with and without prior user turns
- Captures both sides where relevant:
- compaction request shape
- post-compaction history layout shape
- Adds/uses shared request-inspection helpers so assertions target
structured request content instead of ad-hoc JSON string parsing.
- Aligns snapshots/assertions to current behavior and leaves explicit
`TODO(ccunningham)` notes where behavior is known and intentionally
deferred.
## Not Included
- No runtime compaction logic changes.
- No model-visible context/state behavior changes.
