## Why
Multi-agent v2 currently routes agent instructions through normal tool
arguments and inter-agent context. That means the parent model can emit
plaintext task text, Codex can persist it in history/rollouts, and the
recipient can receive it as ordinary assistant-message JSON.
This changes the v2 path so agent instructions stay encrypted between
model calls: Responses encrypts the `message` argument returned by the
model, Codex forwards only that ciphertext, and Responses decrypts it
internally for the recipient model.
## What changed
- Mark the v2 `message` parameter as encrypted for `spawn_agent`,
`send_message`, and `followup_task`.
- Treat multi-agent v2 tool `message` values as ciphertext
unconditionally.
- Store v2 inter-agent task text in
`InterAgentCommunication.encrypted_content` with empty plaintext
`content`.
- Convert encrypted inter-agent communications into the Responses
`agent_message` input item before sending the child request.
- Preserve `agent_message` items across history, rollout, compaction,
telemetry, and app-server schema paths.
- Leave multi-agent v1 unchanged.
## Message shape
The model still calls the v2 tools with a `message` argument, but that
value is now ciphertext:
```json
{
"name": "spawn_agent",
"arguments": {
"task_name": "worker",
"message": "<ciphertext>"
}
}
```
Codex stores the task as encrypted inter-agent communication:
```json
{
"author": "/root",
"recipient": "/root/worker",
"content": "",
"encrypted_content": "<ciphertext>",
"trigger_turn": true
}
```
When Codex builds the recipient request, it forwards the ciphertext
using the new Responses input item:
```json
{
"type": "agent_message",
"author": "/root",
"recipient": "/root/worker",
"content": [
{
"type": "encrypted_content",
"encrypted_content": "<ciphertext>"
}
]
}
```
Responses decrypts that item internally for the recipient model.
## Context impact
- Parent context no longer carries plaintext v2 agent task instructions
from these tool arguments.
- Codex rollout/history stores ciphertext for v2 agent instructions.
- Recipient requests receive an `agent_message` item instead of
assistant commentary JSON for encrypted task delivery.
- Plaintext completion/status notifications are still plaintext because
they are Codex-generated status messages, not encrypted model tool
arguments.
## Validation
- `just test -p codex-tools`
- `just test -p codex-protocol`
- `just test -p codex-rollout`
- `just test -p codex-rollout-trace`
- `just test -p codex-otel`
- `just write-app-server-schema`
## Why
Standalone image generation returns image bytes to the model, but the
model also needs the host artifact path to reference the generated file
in follow-up work.
## What changed
- Append the default saved-image path hint alongside the generated image
tool output.
- Reuse the existing core image-generation hint text.
- Pass the thread ID and Codex home directory needed to compute the
artifact path.
- Add app-server and extension coverage for the model-visible hint.
## Validation
- `just fmt`
- `just bazel-lock-check`
- `just test -p codex-app-server
standalone_image_generation_returns_saved_path_hint_to_model`
## Why
Standalone image generation remained top-level-only in code-mode
sessions.
## What changed
- Change imagegen exposure from `DirectModelOnly` to `Direct`.
- Keep direct-mode access while enabling nested code-mode access.
- Add a focused regression test for the exposure contract.
## Validation
- `just test -p codex-image-generation-extension`
## Why
Standalone image-generation extensions emitted turn items through the
low-level event path, bypassing host-owned finalization such as image
persistence and contributor processing. At the same time, the
generated-image save-path hint must remain visible to the model through
the extension tool's `FunctionCallOutput`, rather than the legacy
built-in developer-message path.
## What changed
- Extended `ExtensionTurnItem` to support image-generation items while
keeping the extension-facing emitter API limited to `emit_started` and
`emit_completed`.
- Routed extension completion through core `finalize_turn_item`, so
standalone image-generation items receive host-owned processing and
persisted `saved_path` values before publication.
- Kept legacy built-in image generation on its existing
developer-message hint path, while standalone image generation returns
its deterministic saved-path hint in `FunctionCallOutput`.
- Shared the image artifact path and output-hint formatting used by core
and the image-generation extension.
- Passed thread identity through extension tool calls so standalone
image generation can construct the same intended artifact path as core.
- Added an app-server integration test covering real standalone image
generation, saved artifact publication, model-visible output hint
wiring, and absence of the legacy developer-message hint.
## Validation
- `just fmt`
- `just test -p codex-image-generation-extension`
- `just test -p codex-web-search-extension`
- `just test -p codex-goal-extension`
- `just test -p codex-memories-extension`
- Targeted `codex-core` tests for image save history, extension
completion finalization, and contributor execution
- `just test -p codex-app-server
standalone_image_generation_returns_saved_path_hint_to_model`
- `just fix -p codex-core`
- `just fix -p codex-image-generation-extension`
- `just bazel-lock-update`
- `just bazel-lock-check`
## Why
The standalone `image_gen.imagegen` extension should behave like native
image generation for artifact persistence and UI completion, while
returning its save-location guidance as part of the tool result instead
of injecting a developer message.
## What Changed
- Added an image-generation completion hook for extension tools so core
can persist generated images and emit the existing `ImageGeneration`
lifecycle events.
- Reused core image artifact persistence for extension output and
removed extension-local save-path/file-writing logic.
- Split shared image persistence from built-in finalization so native
image generation keeps its existing developer-message instruction
behavior.
- Returned the generated image save-location instruction through the
extension `FunctionCallOutput`, alongside the generated image input for
model follow-up.
- Preserved the existing image-generation event shape for current UI and
replay compatibility.
- Avoided cloning the full generated-image base64 payload when emitting
the in-progress image item.
- Removed dependencies no longer needed after moving persistence out of
the extension crate.
## Fast Follow
- Adjust the existing Extension API and add a general `TurnItem`
finalization path for re-usability of code
## Validation
- Ran `just fmt`.
- Ran `just bazel-lock-update`.
- Ran `just bazel-lock-check`.
- Ran `just test -p codex-tools -p codex-extension-api -p
codex-image-generation-extension`.
- Ran `just test -p codex-core
image_generation_publication_is_finalized_by_core`.
- Ran `just test -p codex-core
handle_output_item_done_records_image_save_history_message`.
- Ran `just fix -p codex-tools -p codex-extension-api -p codex-core -p
codex-image-generation-extension`.
## Why
Add a standalone image generation path that can be exercised
independently of hosted Responses image generation, while retaining the
hosted tool as fallback unless the extension is actually available to
the model.
## What changed
- Added the `codex-image-generation-extension` crate with standalone
generate/edit execution, prior-image selection for edits, model-visible
image output, and local generated-image persistence.
- Installed the extension in app-server behind the disabled-by-default
`imagegenext` feature and backend eligibility checks.
- Updated core tool planning so eligible `image_gen.imagegen` exposure
replaces hosted `image_generation`, while unavailable configurations
retain hosted fallback.
- Added coverage for extension behavior, edit history reuse, feature
gating, auth eligibility, and hosted-tool replacement.
- The extension is installed through app-server only in this PR; other
execution paths retain hosted image generation because hosted
replacement occurs only when the standalone executor is actually
registered and model-visible.
- The initial extension contract intentionally fixes the image model to
`gpt-image-2` and uses automatic image parameters.
- Native generated-image history/card parity and rollout persistence
cleanup are intentionally deferred follow-up work.
## Validation
- `just test -p codex-image-generation-extension`
- `just test -p codex-features`
- `just test -p codex-core
hosted_tools_follow_provider_auth_model_and_config_gates`
- `just test -p codex-app-server`
- `just fix -p codex-image-generation-extension -p codex-features -p
codex-core -p codex-app-server`
- `just fmt`
- `just bazel-lock-update`
- `just bazel-lock-check`
---------
Co-authored-by: jif-oai <jif@openai.com>
jifandGitHub
Won ParkandGitHub