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codex/codex-rs/core
T
Michael Bolin d2885dc3cd core: stabilize synthesized call output IDs (#30327)
## Why

Response item IDs represent stable conversation identity.
`ContextManager::for_prompt` repairs an unmatched call by synthesizing
an `"aborted"` output in the disposable prompt projection, but that
output previously had no ID. Assigning a fresh ID on every prompt build
would make retries and resumes change otherwise identical model context
and reduce prompt-cache reuse.

The concrete bug is that these normalization-created outputs bypass the
regular item-ID allocation path. Even with item IDs enabled, a prompt
could therefore contain an identified call paired with a synthetic
output whose `id` was missing. This change closes that gap by deriving
the output ID from the source call's item ID. For legacy calls that have
no item ID, the output remains ID-less because there is no stable source
identity to derive from.

The originating call already has a stable item ID under the item-ID
model introduced in #28814. A prompt-only output can therefore derive
stable identity from that call without mutating canonical history or
persisted rollouts. This addresses the failure exposed by #30311 while
keeping normalization read-only outside its detached prompt snapshot.

UUIDv5 is intentional here because it is the standard namespaced,
deterministic UUID construction. Using the output kind and source call
ID as the name produces the same UUID on every projection while keeping
output kinds in separate name domains. UUIDv7 would introduce randomness
and time, so keeping it stable would require persisting the synthetic
repair. UUIDv5 uses SHA-1 internally, but this is only an identity
mapping—not an authenticity or security boundary.

## What changed

- Derive a deterministic UUIDv5 ID for each synthesized call output from
the source call item ID.
- Use the Responses API prefix appropriate for function, custom-tool,
tool-search, and local-shell outputs.
- Preserve the existing insertion position immediately after the
unmatched call.
- Keep synthesized outputs prompt-only; no rollout, task-lifecycle,
compaction, or raw-response behavior changes.

## Testing

- `just test -p codex-core
for_prompt_assigns_stable_id_to_synthetic_output_without_reordering_history`
- `just test -p codex-core
synthetic_call_output_id_is_stable_across_resumes`
- `just test -p codex-core normalize_adds_missing_output`
- `just test -p codex-core response_item_ids`
d2885dc3cd · 2026-06-27 10:47:54 -07:00
History
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codex-core

This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.

Wine-exec integration tests

On x86-64 Linux, run the shared suite against the Windows exec server with bazel test //codex-rs/core:core-all-wine-exec-test.

Local execution targets the host OS, Docker targets Linux, and Wine exec targets Windows. Choose the skip macro by what the test depends on:

  • skip_if_target_windows!: Windows target behavior.
  • skip_if_host_windows!: Windows host constraints.
  • skip_if_remote!: Local-only test behavior.
  • skip_if_no_remote_env!: Remote-only test behavior.
  • skip_if_wine_exec!: Wine-specific runner debt.

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 keeps the legacy default preferences read access (user-preference-read) needed for cfprefs-backed macOS behavior.

Linux

Expects the binary containing codex-core to run the equivalent of codex sandbox when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.

Legacy SandboxPolicy / sandbox_mode configs are still supported on Linux. They can continue to use the legacy Landlock path when the split filesystem policy is sandbox-equivalent to the legacy model after cwd resolution. Split filesystem policies that need direct FileSystemSandboxPolicy enforcement, such as read-only or denied carveouts under a broader writable root, automatically route through bubblewrap. The legacy Landlock path is used only when the split filesystem policy round-trips through the legacy SandboxPolicy model without changing semantics. That includes overlapping cases like /repo = write, /repo/a = none, /repo/a/b = write, where the more specific writable child must reopen under a denied parent.

The Linux sandbox helper prefers the first bwrap found on PATH outside the current working directory whenever it is available. If bwrap is present but too old to support --argv0, the helper keeps using system bubblewrap and switches to a no---argv0 compatibility path for the inner re-exec. If bwrap is missing, it falls back to the bundled codex-resources/bwrap binary shipped with Codex and Codex surfaces a startup warning through its normal notification path instead of printing directly from the sandbox helper. Codex also surfaces a startup warning when bubblewrap cannot create user namespaces. WSL2 uses the normal Linux bubblewrap path. WSL1 is not supported for bubblewrap sandboxing because it cannot create the required user namespaces, so Codex rejects sandboxed shell commands that would enter the bubblewrap path before invoking bwrap.

Windows

Legacy SandboxPolicy / sandbox_mode configs are still supported on Windows. Legacy read-only and workspace-write policies imply full filesystem read access; exact readable roots are represented by split filesystem policies instead.

The elevated Windows sandbox also supports:

  • legacy ReadOnly and WorkspaceWrite behavior
  • split filesystem policies that need exact readable roots, exact writable roots, or extra read-only carveouts under writable roots
  • backend-managed system read roots required for basic execution, such as C:\Windows, C:\Program Files, C:\Program Files (x86), and C:\ProgramData, when a split filesystem policy requests platform defaults

The unelevated restricted-token backend still supports the legacy full-read Windows model for legacy ReadOnly and WorkspaceWrite behavior. It also supports a narrow split-filesystem subset: full-read split policies whose writable roots still match the legacy WorkspaceWrite root set, but add extra read-only carveouts under those writable roots.

New [permissions] / split filesystem policies remain supported on Windows only when they can be enforced directly by the selected Windows backend or round-trip through the legacy SandboxPolicy model without changing semantics. Policies that would require direct explicit unreadable carveouts (none) or reopened writable descendants under read-only carveouts still fail closed instead of running with weaker enforcement.

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.