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.
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Dependencies
Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this support matrix is:
macOS
Expects /usr/bin/sandbox-exec to be present.
When using the workspace-write sandbox policy, the Seatbelt profile allows
writes under the configured writable roots while keeping .git (directory or
pointer file), the resolved gitdir: target, and .codex read-only.
Network access and filesystem read/write roots are controlled by
SandboxPolicy. Seatbelt consumes the resolved policy and enforces it.
Seatbelt also supports macOS permission-profile extensions layered on top of
SandboxPolicy:
- no extension profile provided:
keeps legacy default preferences read access (
user-preference-read). - extension profile provided with no
macos_preferencesgrant: does not add preferences access clauses. macos_preferences = "readonly": enables cfprefs read clauses anduser-preference-read.macos_preferences = "readwrite": includes readonly clauses plususer-preference-writeand cfprefs shm write clauses.macos_automation = true: enables broad Apple Events send permissions.macos_automation = ["com.apple.Notes", ...]: enables Apple Events send only to listed bundle IDs.macos_accessibility = true: enablescom.apple.axservermach lookup.macos_calendar = true: enablescom.apple.CalendarAgentmach lookup.
Linux
Expects the binary containing codex-core to run the equivalent of codex sandbox linux (legacy alias: codex debug landlock) when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.
All Platforms
Expects the binary containing codex-core to simulate the virtual apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the codex-arg0 crate for details.