## Why
The token-budget feature currently adds remaining-token messages
whenever usage crosses the 25%, 50%, and 75% thresholds. Those periodic
inserts create prompt churn without requiring action, while the
near-compaction reminder and explicit `get_context_remaining` tool
already cover actionable and on-demand budget information.
The context-window lineage block is also easier to scan as plain labeled
text than as a `<token_budget>`-wrapped fragment.
## What changed
- Stop recording automatic remaining-token messages at percentage
thresholds.
- Render context-window lineage in `First`, `Current`, `Previous` order
with colon-separated labels.
- Omit the `Previous` line for the first context window.
- Remove `<token_budget>` wrappers from newly rendered lineage,
near-compaction reminders, and `get_context_remaining` output.
- Keep recognizing legacy wrapped fragments so existing rollouts remain
compatible.
- Remove the post-sampling token snapshot that was only needed by the
periodic threshold path.
## Testing
- `just test -p codex-core token_budget` (11 tests passed)
## Why
Prototype whether the harness can invoke the `mcp_history` MCP while
constructing full initial context and expose its thread hint to the
model without requiring a model-issued tool call.
The prototype builds on the context-window lineage added by #29256 and
is now based directly on `main`.
## What changed
- Call `mcp_history/thread_hint` with no arguments while building the
full `<token_budget>` context.
- Pass the current `threadId` through MCP request metadata, matching the
normal MCP tool-call path.
- Serialize only the unstructured `content` result and append it inside
`<token_budget>` when the call succeeds.
- Omit the additional context when the MCP call or content serialization
fails.
## Prototype limitations
- The direct call bypasses the normal model-initiated MCP approval,
lifecycle-event, telemetry, and result-sanitization path.
- The call has no prototype-specific timeout, result-size cap, or
per-window cache.
- MCP latency is added to full-context construction, including
applicable compaction paths.
## Validation
- `just test -p codex-core token_budget`
## Why
The rendered `<token_budget>` fragment identifies the thread and current
context window, but it does not expose enough lineage to identify the
first window in the thread or the immediately preceding window. Those
IDs also need to remain stable across compaction, resume, and rollback.
## What changed
- Track first, previous, and current UUIDv7 context-window IDs in
auto-compaction state.
- Render `thread_id`, `first_window_id`, `previous_window_id`, and the
current window ID in the full `<token_budget>` fragment.
- Persist the first and previous window IDs in compacted rollout
checkpoints and restore them during rollout reconstruction.
- Preserve compatibility with older compacted records that do not
contain the new optional fields.
- Update focused state, rendering, reconstruction, rollback, and
serialization coverage.
## Validation
- `just test -p codex-core token_budget`
- `just test -p codex-protocol compacted_item::tests`
- `just test -p codex-core tracks_prefill_and_window_boundaries`
- `just test -p codex-core
reconstruct_history_uses_replacement_history_verbatim`
- `just test -p codex-core
thread_rollback_restores_cleared_reference_context_item_after_compaction`
## Why
The token-budget context currently identifies a context window by its
thread-local sequence number. A UUIDv7 gives the model a stable opaque
identity that remains fixed for a window and rotates when compaction or
`new_context` starts the next one.
## What changed
- Preserve the existing monotonic value as `window_number` and add a
UUIDv7 `window_id` to `CompactedItem`.
- Generate and rotate the UUID with auto-compaction window state,
persist it alongside the number, and reconstruct it on resume and
rollback.
- Accept legacy compacted rollout records where the numeric `window_id`
represented the window number.
- Use the UUID only in token-budget context; existing request headers
and metadata continue using `thread_id:window_number`.
## Testing
- `just test -p codex-protocol compacted_item::tests`
- `just test -p codex-core token_budget`
## Why
Multi-agent v2 `send_message` deliveries already reach the receiving
model as typed `agent_message` items with encrypted content.
Child-completion notifications are generated by Codex itself, so their
content is plaintext and previously fell back to a serialized JSON
envelope inside an assistant message.
With plaintext `input_text` supported for `agent_message`, both delivery
paths can use the same model-visible type while preserving explicit
author and recipient metadata.
## What changed
- add plaintext `input_text` support to `AgentMessageInputContent` and
regenerate the affected app-server schemas
- preserve `InterAgentCommunication` as structured mailbox input instead
of converting it to assistant text
- record delivered communications as typed `agent_message` history items
- persist a dedicated rollout item so local delivery metadata such as
`trigger_turn` remains available without leaking into the Responses
request
- reconstruct typed agent messages on resume and preserve fork-turn
truncation behavior
- remove request-time assistant-content parsing
- preserve plaintext and encrypted inter-agent deliveries in stage-one
memory inputs
- normalize and link plaintext and encrypted agent messages in rollout
traces without treating inbound messages as child results
- cover the real MultiAgent V2 child-completion path end to end with
deterministic mailbox synchronization
## Verification
- `just test -p codex-core
plaintext_multi_agent_v2_completion_sends_agent_message`
- `just test -p codex-core input_queue_drains_mailbox_in_delivery_order
record_initial_history_reconstructs_typed_inter_agent_message
fork_turn_positions_use_inter_agent_delivery_metadata`
- `just test -p codex-memories-write
serializes_inter_agent_communications_for_memory`
- `just test -p codex-rollout-trace
agent_messages_preserve_routing_and_content
sub_agent_started_activity_creates_spawn_edge`
- `just test -p codex-rollout-trace
agent_result_edge_falls_back_to_child_thread_without_result_message`
- `just test -p codex-protocol -p codex-rollout -p
codex-app-server-protocol`
## Why
The token budget full-context fragment identifies the current context
window, but not the thread that owns that window. Including the thread
id makes the initial context-window metadata self-contained, and
`get_context_remaining` also needs to be usable from Code Mode without
forcing callers to parse the model-facing fragment string.
## What changed
- Include the session thread id in the initial `<token_budget>` context
fragment.
- Expose `get_context_remaining` as a Code Mode nested tool while
keeping `new_context` direct-model-only.
- Keep direct model-facing `get_context_remaining` output as the
existing `<token_budget>` text fragment.
- Return only `tokens_left` from the Code Mode structured result for
`get_context_remaining`.
- Update token-budget integration tests and add Code Mode coverage for
the structured result.
## Verification
- `just test -p codex-core token_budget`
- `just test -p codex-core
code_mode_get_context_remaining_returns_structured_result`
- `just test -p core_test_support redacted_text_mode_normalizes_uuids`
## What
Introduce a `CodexResponsesMetadata` struct that defines all the core
metadata we send to Responses API. Example fields are `thread_id`,
`turn_id`, `window_id`, etc.
Going forward, `client_metadata["x-codex-turn-metadata"]` will be the
canonical way Codex sends metadata to Responses API across both HTTP and
websocket transports.
For now, we continue to emit the existing top-level HTTP headers and
top-level `client_metadata` fields from the same
`CodexResponsesMetadata` struct for compatibility reasons.
Also, app-server clients who specify additional
`responsesapi_client_metadata` via `turn/start` and `turn/steer` will
have those fields merged into
`client_metadata["x-codex-turn-metadata"]`, but cannot override the
reserved fields that core uses (i.e. the fields in
`CodexResponsesMetadata`).
## Why
Responses API request instrumentation is the source of truth for
downstream Codex analytics that join requests by Codex IDs such as
session, thread, turn, and context window. Before this change, those
values were assembled through several request-specific paths: HTTP
request bodies, websocket handshake headers, websocket `response.create`
payloads, compaction requests, and the rich `x-codex-turn-metadata`
envelope all had their own wiring.
That made metadata propagation easy to drift across API-key/direct
Responses API requests, ChatGPT-auth/proxied requests, websocket
requests, and compaction requests. It also made additions like
`window_id` error-prone because a field could be added to one transport
projection but missed in another.
## What changed
- Added `CodexResponsesMetadata` as the core-owned snapshot for Codex
metadata sent to ResponsesAPI.
- Render `client_metadata["x-codex-turn-metadata"]`, flat
`client_metadata` projections, and direct compatibility headers from
that same snapshot.
- Include the known Codex-owned fields in the turn metadata blob,
including installation/session/thread/turn/window IDs, request kind,
lineage, sandbox/workspace metadata, timing, and compaction details.
- Treat app-server `responsesapi_client_metadata` as enrichment for the
Codex turn metadata blob while preventing those extras from overriding
Codex-owned fields.
- Use the same metadata path for normal turns, websocket prewarm, local
compaction, remote v1 compaction, and remote v2 compaction.
- Keep websocket connection-only preconnect metadata separate so
handshakes carry compatibility identity headers without inventing a fake
turn metadata blob.
## Verification
- `cargo check -p codex-core`
- `just fix -p codex-core`
## Why
The token budget feature tells the model how much room remains in the
current context window. When the model decides the current window is no
longer useful, it needs a way to ask Codex to start over with a fresh
context window without spending tokens on a compaction summary.
This PR adds that model-requestable escape hatch on top of #27438.
## What changed
- Added a direct-model-only `new_context` tool behind
`Feature::TokenBudget`.
- Stores the tool request on `AutoCompactWindow` and consumes it after
sampling so the next follow-up request in the same turn starts in the
new window.
- Starts the new window as a no-summary compaction checkpoint that
contains only fresh initial context, not preserved conversation history.
- Keeps the new window aligned with token-budget startup context,
including the `Current context window Z` message.
- Added integration coverage and a snapshot showing the same-turn
`new_context` flow into a fresh full-context follow-up request.
## Validation
- `just test -p codex-core token_budget`
## Why
The realtime frontend model and the backing Codex thread should present
one coherent assistant. Raw typed messages, steers, and worker reports
belong to the orchestrator; the frontend model should receive the
orchestrator's user-facing result rather than a second copy of those
inputs.
Today normal `turn/start` input is automatically inserted into the
realtime conversation, while `turn/steer` is not. Besides creating
inconsistent context, this can make the frontend model react
independently before Codex has produced the response it should speak.
## What changed
- Remove automatic accepted-user-input mirroring into realtime
- Remove the mirror-only echo-suppression flag and dead V2 prefix helper
- Preserve explicit app-to-realtime text injection and FEM-to-Codex
delegation
- Replace the positive mirror tests and obsolete snapshots with a
negative routing regression test
## Test plan
- `cargo test -p codex-core
conversation_user_text_turn_is_not_sent_to_realtime`
- `cargo test -p codex-core
conversation_startup_context_is_truncated_and_sent_once_per_start`
- `cargo test -p codex-core inbound_handoff_request_starts_turn`
## Summary
- Keep the existing `x-codex-window-id` HTTP header unchanged.
- Also send the same window ID in Responses `client_metadata`, allowing
supported backend paths to surface it as
`x-client-meta-x-codex-window-id`.
- Cover normal HTTP Responses and remote compaction v2 requests without
changing window generation or compaction behavior.
## Why
In the `2026-06-06T23` production hour, all 28,729 HTTP compaction
requests had `window_id` in `x-codex-turn-metadata`, but only 73
retained the direct `x-codex-window-id` header. The request-body
`client_metadata` path is already used for installation ID and is
preserved through supported Responses API paths.
This is additive metadata only. It does not change the direct header,
request count, model input, compaction routing, window generation, or
user response behavior.
Legacy `/v1/responses/compact` is intentionally unchanged. Its current
server-side `CompressBody` schema does not accept `client_metadata` and
rejects unknown fields, so supporting that path requires a backend
schema change before the Codex client can safely send this field.
## Validation
- Current head: `219baef3c`, rebased onto `origin/main` at `26d932983`.
- The post-rebase diff remains limited to the original five files (`22`
insertions, `6` deletions); the legacy experiment remains fully
reverted.
- `just test -p codex-core
responses_stream_includes_subagent_header_on_review`: passed; validates
normal HTTP Responses metadata.
- `just test -p codex-core
remote_compact_v2_reuses_compaction_trigger_for_followups`: passed;
validates remote compaction v2.
- `just test -p codex-core
remote_manual_compact_chatgpt_auth_reuses_service_tier_and_prompt_cache_key`:
passed; validates that legacy compact keeps its accepted payload shape.
- `just test -p codex-core
remote_manual_compact_api_auth_omits_service_tier_and_reuses_prompt_cache_key`:
passed; validates the legacy API-key payload as well.
- `just fmt`: passed; an unrelated root `justfile` rewrite produced by
the formatter was discarded.
- `git diff --check origin/main...HEAD`: passed.
The focused server pytest could not start in the local monorepo
environment because test setup is missing the `dotenv` module. Server
source and tests explicitly show that `CompressBody` omits
`client_metadata` and `/v1/responses/compact` returns HTTP 400 for
unknown body fields.
## Why
Remote image submissions currently wrap native `input_image` spans in
literal `<image>` and `</image>` text spans. Those extra prompt tokens
add structure without providing label or routing information.
## What Changed
- Serialize `UserInput::Image` directly as an `input_image` content
span.
- Preserve named local-image framing and legacy wrapper parsing for
labeled attachments and existing histories.
- Update existing request-shape expectations for drag-and-drop images,
model switching, and compaction.
## Validation
- `just test -p codex-protocol`
- Focused `codex-core` run covering
`drag_drop_image_persists_rollout_request_shape`,
`model_change_from_image_to_text_strips_prior_image_content`, and
`snapshot_request_shape_pre_turn_compaction_including_incoming_user_message`
## Notes
- A broader `just test -p codex-core` run was attempted; the affected
tests passed, while the overall run failed in unrelated CLI, MCP, and
tooling tests plus a `thread_manager` timeout.
## Summary
Adds experimental `additionalContext` support to `turn/start` and
`turn/steer` so clients can provide ephemeral external context, such as
browser or automation state, without turning that plumbing into a
visible user prompt or triggering user-prompt lifecycle behavior.
## API Shape
The parameter shape is:
```ts
additionalContext?: Record<string, {
value: string
kind: "untrusted" | "application"
}> | null
```
Example:
```json
{
"additionalContext": {
"browser_info": {
"value": "Active tab is CI failures.",
"kind": "untrusted"
},
"automation_info": {
"value": "CI rerun is in progress.",
"kind": "application"
}
}
}
```
The keys are opaque and caller-defined.
## Context Injection
When provided, accepted entries are inserted into model context as
hidden contextual message items, not as visible thread user-message
items.
`kind: "untrusted"` entries are inserted with role `user`:
```text
<external_${key}>${value}</external_${key}>
```
`kind: "application"` entries are inserted with role `developer`:
```text
<${key}>${value}</${key}>
```
Values are not escaped. Each value is truncated to 1k approximate tokens
before wrapping.
For `turn/start`, accepted additional context is inserted before normal
user input. For `turn/steer`, additional context is merged only when the
steer includes non-empty user input; context-only steers still reject as
empty input.
## Dedupe Strategy
`AdditionalContextStore` lives on session state and stores the latest
complete additional-context map.
Each `turn/start` or non-empty `turn/steer` treats its
`additionalContext` as the current complete set of values. Entries are
injected only when the key is new or the exact entry for that key
changed, including `value` or `kind`. After merging, the store is
replaced with the provided map, so omitted keys are removed from the
retained set and can be injected again later if reintroduced.
Omitting `additionalContext`, passing `null`, or passing an empty object
resets the store to empty and injects nothing.
## What Changed
- Threads experimental v2 `additionalContext` through app-server into
core turn start and steer handling.
- Adds separate contextual fragment types for untrusted user-role
context and application developer-role context.
- Uses pending response input items so additional context can be
combined with normal user input without treating it as prompt text.
- Adds integration coverage for start/steer flow, role routing,
dedupe/reset behavior, deletion/re-add behavior, hook-blocked input
behavior, empty context-only steer rejection, external-fragment marker
matching, and truncation.
## Why
Recent session history showed no active use of the raw `shell`,
`local_shell`, or `container.exec` execution surfaces. Keeping those
handlers/specs wired into core leaves duplicate shell execution paths
alongside the supported `shell_command` and unified exec tools.
## What changed
- Removed the raw `shell` handler/spec and its `ShellToolCallParams`
protocol helper.
- Removed the legacy `local_shell` and `container.exec` handler/spec
plumbing while preserving persisted-history compatibility for old
response items.
- Normalized model/config `default` and `local` shell selections to
`shell_command`.
- Pruned tests that exercised removed raw-shell/local-shell/apply-patch
variants and kept coverage on `shell_command`, unified exec, and
freeform `apply_patch`.
## Verification
- `git diff --check`
- `cargo test -p codex-protocol`
- `cargo test -p codex-tools`
- `cargo test -p codex-core tools::handlers::shell`
- `cargo test -p codex-core tools::spec`
- `cargo test -p codex-core tools::router`
- `cargo test -p codex-core
active_call_preserves_triggering_command_context`
- `cargo test -p codex-core guardian_tests`
- `cargo test -p codex-core --test all shell_serialization`
- `cargo test -p codex-core --test all apply_patch_cli`
- `cargo test -p codex-core --test all shell_command_`
- `cargo test -p codex-core --test all local_shell`
- `cargo test -p codex-core --test all otel::`
- `cargo test -p codex-core --test all hooks::`
- `just fix -p codex-core`
- `just fix -p codex-tools`
## Summary
API-key-auth remote compaction requests should not inherit
`service_tier` from normal `/responses` turns. This path needs to match
API auth expectations, while ChatGPT-auth remote compaction should keep
reusing the shared request fields that still apply there.
This change keeps the decision inline in
`codex-rs/core/src/compact_remote.rs` only. Under API key auth, the
classic remote `/responses/compact` path now omits `service_tier`; under
ChatGPT auth, it keeps reusing the configured tier.
`codex-rs/core/src/compact_remote_v2.rs` is unchanged. The remote
compaction parity coverage and snapshots were updated to assert the
API-key omission and preserve the ChatGPT-auth behavior.
## Testing
- Updated remote compaction parity coverage in
`codex-rs/core/tests/suite/compact_remote.rs` and the corresponding
snapshots.
## Why
`/responses/compact` should preserve the request-affinity fields that
apply to the active auth mode. ChatGPT-auth compact requests need the
effective `service_tier`, and compact requests for every auth mode need
the stable `prompt_cache_key`, so compaction does not quietly lose
routing or cache behavior that normal sampling already has.
This follows the request-parity direction from #20719, but keeps the net
change focused on the compact payload fields needed here.
## What changed
- Add `service_tier` and `prompt_cache_key` to the compact endpoint
input payload.
- Build the remote compact payload from the existing responses request
builder output so `Fast` still maps to `priority` when compact sends a
service tier.
- Pass the turn service tier into remote compaction, but only include it
in compact payloads for ChatGPT-backed auth.
- Keep `prompt_cache_key` on compact payloads for all auth modes.
- Add request-body diff snapshot coverage in
`core/tests/suite/compact_remote.rs` for:
- API-key auth reusing `prompt_cache_key` while omitting `service_tier`
even when `Fast` is configured.
- ChatGPT auth reusing both `service_tier` and `prompt_cache_key`.
- Drive the snapshot coverage through five varied turns: plain text,
multi-part text, tool-call continuation, image+text input, local-shell
continuation, and final-turn reasoning output.
## Verification
- Added insta snapshots for compact request-body parity against the last
normal `/responses` request after five varied turns.
- Not run locally per repo guidance; relying on GitHub CI for test
execution.
---------
Co-authored-by: Codex <noreply@openai.com>
## Summary
- Reverts PR #17749 so queued inter-agent mail can again preempt after
reasoning/commentary output item boundaries.
- Applies the revert to the current `codex/turn.rs` module layout and
restores the prior pending-input test expectations/snapshots.
## Testing
- `just fmt`
- `cargo test -p codex-core --test all pending_input`
- `cargo test -p codex-core` failed in unrelated
`tools::js_repl::tests::js_repl_imported_local_files_can_access_repl_globals`:
dotslash download hit `mktemp: mkdtemp failed ... Operation not
permitted` in the sandbox temp dir.
Co-authored-by: Codex <noreply@openai.com>
## Summary
- wrap realtime startup context in
`<startup_context>...</startup_context>` tags
- prefix V2 mirrored user text and relayed backend text with `[USER]` /
`[BACKEND]`
- remove the V2 progress suffix and replace the final V2 handoff output
with a short completion acknowledgement while preserving the existing V1
wrapper
## Testing
- cargo test -p codex-api
realtime_v2_session_update_includes_background_agent_tool_and_handoff_output_item
-- --exact
- cargo test -p codex-app-server webrtc_v2_background_agent_
- cargo test -p codex-app-server webrtc_v2_text_input_is_
- cargo test -p codex-core conversation_user_text_turn_is_
This changes multi-agent v2 mailbox handling so incoming inter-agent
messages no longer preempt an in-flight sampling stream at reasoning or
commentary output-item boundaries.
Cap mirrored user text sent to realtime with the existing 300-token turn
budget while preserving the full model turn.
Adds integration coverage for capped realtime mirror payloads.
---------
Co-authored-by: Codex <noreply@openai.com>
- Let typed user messages submit while realtime is active and mirror
accepted text into the realtime text stream.
- Add integration coverage and snapshot for outbound realtime text.
Select Current Thread startup context by budget from newest turns, cap
each rendered turn at 300 approximate tokens, and add formatter plus
integration snapshot coverage.
Send pending mailbox mail after completed reasoning or commentary items
so follow-up requests can pick it up mid-turn.
---------
Co-authored-by: Codex <noreply@openai.com>
## Summary
- trim contiguous developer/contextual-user pre-turn updates when
rollback cuts back to a user turn
- add a focused history regression test for the trim behavior
- update the rollback request-boundary snapshots to show the fixed
non-duplicating context shape
---------
Co-authored-by: Codex <noreply@openai.com>
## What changed
- adds a targeted snapshot test for rollback with contextual diffs in
`codex_tests.rs`
- snapshots the exact model-visible request input before the rolled-back
turn and on the follow-up request after rollback
- shows the duplicate developer and environment context pair appearing
again before the follow-up user message
## Why
Rollback currently rewinds the reference context baseline without
rewinding the live session overrides. On the next turn, the same
contextual diff is emitted again and duplicated in the request sent to
the model.
## Impact
- makes the regression visible in a canonical snapshot test
- keeps the snapshot on the shared `context_snapshot` path without
adding new formatting helpers
- gives a direct repro for future fixes to rollback/context
reconstruction
---------
Co-authored-by: Codex <noreply@openai.com>
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.
pakrym-oaiandGitHub
jifandGitHub
Owen LinandGitHub
guinness-oaiandGitHub
ningyi-oaiandGitHub
Ahmed IbrahimandGitHub
bxie-openaiandGitHub
Thibault SottiauxandGitHub
