[mmabrouk]

Do not merge into main. This PR waits for the next release branch.

Problem

There are two ways to stop an agent turn. POST /sessions/{session_id}/cancel queues a durable stop, and the runner keeps the partial answer. The older stop mode of POST /sessions/streams/ (a call with no inputs and no force) clears the running owner at once. Since v0.124.0 that made the runner drop the partial answer. #7827 made the old path safe, and we agreed to retire it after external callers get notice.

Our own code still called the old stop mode in two places: the /w tab close and the channel !stop command. The web package also kept two helpers that used it.

Change

• The /w tab close now calls cancelSessionExecution. This path is still switched off (CLOSE_CANCELS_RUN = false), so nothing changes for users today.
• The channel !stop command now calls SessionCommandsService.request_cancel, the same service the cancel route uses. Both channel dispatchers (API and worker) get the commands service. No channel offers !stop today, so this is also dormant.
• Removed the unused web helpers cancelSessionStream and commandSessionStream, their response schema, and their test.
• The set_session_stream route now has an OpenAPI description that marks the stop mode deprecated. The API reference page carries the same note. Send, steer and attach are not deprecated.
• The route logs each call in stop mode, so we can count the remaining callers before we remove the mode.

The stop mode itself stays. We remove it one or two releases later.

Closing the /w browser tab does not stop a turn

On staging (v0.125.2), closing the /w browser tab during an answer did not stop the turn. This is expected, and this PR does not change it:

• Nothing in /w sends a stop when the browser tab closes. The code this PR changes in AgentChatPanel.tsx runs when a user closes a session tab inside the chat, not the browser tab.
• Even that session-tab stop is switched off today (CLOSE_CANCELS_RUN = false in closeSessionCancel.ts). This PR only changes which route it would call if someone turns it on.
• A turn that keeps running after the browser tab closes is the right behavior. /m works the same way, and the user sees the finished answer when they come back. So this PR adds no stop on browser-tab close.

Tests

• Channel command tests now assert request_cancel.
• Removed the test that a channel stop creates an ownerless session row. The new path creates no row.
• Kept test_cancel_cancels_pending_interactions.py and the "stream cancel" probe row, because the old route is still public. Both have a note to delete them with the mode.
• Ran 2600 API unit tests (channels and sessions), 2584 @agenta/entities unit tests, and the @agenta/entities and web/oss type checks. All pass.
• A Codex review approved the change with no regression found.

Before anyone turns on !stop or the tab-close cancel

These gaps existed before this PR:

• A redelivered message can stop a later turn, because the call sends no idempotency key.
• The channel reply says "Stopping the current run" even when nothing runs.
• The channel path does not check that the installation may act on the session.

[github-actions]

📘 Docs preview

Status	✅ Ready
Preview	https://pr-7835-agenta-docs-preview.mahmoud-637.workers.dev/docs/
Inspect	Actions run
Commit	668b4a43597e3faf8f664a1d761303d9c5517b4e

Pages changed in this pull request

• Set Session Stream

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[coderabbitai]

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Recent review info

Run configuration

• Source mode: Auto
• Repository: Agenta-AI/agenta
• Branch: fix/deprecate-stream-stop-mode
• File: .coderabbit.yaml
• Commit: 668b4a4
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Commits

Reviewing files that changed from the base of the PR and between 4957b15 and 668b4a4.

Files selected for processing: 9

• api/entrypoints/routers.py
• api/entrypoints/worker_queues.py
• api/oss/src/apis/fastapi/sessions/router.py
• api/oss/src/core/channels/commands.py
• api/oss/src/tasks/asyncio/channels/inbox.py
• api/oss/tests/pytest/integration/channels/test_channels_composition_seam.py
• api/oss/tests/pytest/unit/channels/test_channels_commands.py
• api/oss/tests/pytest/unit/sessions/test_cancel_cancels_pending_interactions.py
• api/oss/tests/pytest/unit/sessions/test_insert_paths_require_access.py

Files with no reviewable changes: 1

• api/oss/tests/pytest/unit/sessions/test_insert_paths_require_access.py

Files skipped from review as they are similar to previous changes: 1

• api/oss/tests/pytest/unit/sessions/test_cancel_cancels_pending_interactions.py

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📝 Summary

Summary by CodeRabbit

• Updates
  • Stopping a run with !stop or closing an eligible chat now uses the session cancellation flow.
• Documentation
  • The stream endpoint’s stop mode is marked deprecated. Use the session cancellation endpoint to stop a running turn.
  • The stream endpoint documentation clarifies how it sends, steers, or attaches to a turn.

Channel !stop now requests cancellation through SessionCommandsService. The web chat panel uses cancelSessionExecution, and the stream-command and stream-cancellation client APIs are removed. The stream endpoint documents its deprecated stop mode and logs requests that derive cancel mode.

Changes: Session cancellation and stream stop mode

Layer / File(s)	Summary
Channel stop dispatch and service wiring api/oss/src/core/channels/commands.py, api/oss/src/tasks/asyncio/channels/inbox.py, api/entrypoints/routers.py, api/entrypoints/worker_queues.py, api/oss/tests/pytest/integration/channels/*, api/oss/tests/pytest/unit/channels/*, api/oss/tests/pytest/unit/sessions/test_insert_paths_require_access.py	Channel !stop calls SessionCommandsService.request_cancel with project, user, and session IDs. Startup configures the service with the direct control-delivery adapter and passes it to InboxDispatcher. Related tests use the commands service; the ownerless-policy channel test is removed.
Web client cancellation API web/oss/src/components/AgentChatSlice/AgentChatPanel.tsx, web/packages/agenta-entities/src/session/api/api.ts, web/packages/agenta-entities/src/session/core/schema.ts, web/packages/agenta-entities/src/session/index.ts, web/packages/agenta-entities/tests/unit/session-cancel-stream.test.ts	The chat panel calls cancelSessionExecution when its existing close-time condition is met. The stream-command and stream-cancellation APIs, response schema and exports, and cancellation API test suite are removed.
Deprecated stream stop mode documentation and logging api/oss/src/apis/fastapi/sessions/router.py, docs/docs/reference/api/set-session-stream.api.mdx, api/oss/tests/pytest/acceptance/sharing/test_private_session_probe.py, api/oss/tests/pytest/unit/sessions/test_cancel_cancels_pending_interactions.py	The endpoint and API documentation describe the deprecated stop condition and direct callers to the cancel endpoint. The route logs project and session IDs when the derived command mode is cancel. Related test comments identify the deprecated mode.

Priority: Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant InboxDispatcher
  participant dispatch_command
  participant SessionCommandsService
  InboxDispatcher->>dispatch_command: Dispatch channel command
  dispatch_command->>SessionCommandsService: request_cancel(project_id, user_id, session_id)

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Possibly related issues

• Agenta-AI/agenta issue 7131: The PR changes the channel !stop cancellation call, but does not change inbox deduplication or add an idempotency key.
• Agenta-AI/agenta issue 7760: The PR moves channel and web stop callers to cancellation APIs, but does not change runner-side delivery for unscoped runs.

Merge Risk: Minimal · up to 668b4

Legacy stream stop remains available, and built-in channels do not offer !stop. No merge-blocking issue was identified.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 50.00% which is insufficient. The required threshold is 60.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documenta…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Title check		The title names the main change: the last stop callers move to the cancel route, and the stream stop mode is deprecated. The raw summary confirms the channel !stop path, the web helper removal, and th…
Description check		The description states the problem, the change, and the scope. It covers the /w tab close and channel !stop callers, the removed web helpers, the deprecation notes, the logging, the tests run, and the…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title names the main change: the last stop callers move to the cancel route, and the stream stop mode is deprecated. The raw summary confirms the channel !stop path, the web helper removal, and the OpenAPI deprecation note. The title uses the 'fix(api)' prefix, which fits a deprecation-and-reroute change, and it is 91 characters, slightly long but still specific.

Full details: Description check

Explanation

The description states the problem, the change, and the scope. It covers the /w tab close and channel !stop callers, the removed web helpers, the deprecation notes, the logging, the tests run, and the known gaps. The description is detailed and clearly related to the changeset.

Full details: Docstring Coverage

Explanation

Docstring coverage is 50.00% which is insufficient. The required threshold is 60.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 4 functions across 9 files.

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

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[github-actions]

Website preview

Preview URL: https://pr-7835-agenta-website-preview.mahmoud-637.workers.dev

Built from 668b4a43597e3faf8f664a1d761303d9c5517b4e. This comment updates in place on every push.

[coderabbitai]

🧹 Nitpick comments: 1

web/oss/src/components/AgentChatSlice/AgentChatPanel.tsx: 1

123-123: Trivial · Data Integrity & Integration · Quick win

Bind close-time cancellation to the observed execution.

When enabled, this call sends neither expectedExecutionId nor idempotencyKey. The endpoint then resolves the current eligible execution. A delayed close request can cancel a later execution that started before the request arrives. Pass the session's tracked execution ID and a stable key for close retries, or keep this path disabled until those values are available.

---

Review info

Run configuration

• Source mode: Auto
• Repository: Agenta-AI/agenta
• Branch: fix/deprecate-stream-stop-mode
• File: .coderabbit.yaml
• Commit: 4957b15
• Layers: Repository YAML (base), Organization UI (inherited)
• Review profile: CHILL
• Plan: Advanced
• Run ID: 698263db-9b76-4c04-9ca9-872cfd24300d

Commits

Reviewing files that changed from the base of the PR and between dd43c87 and 4957b15.

Files selected for processing: 16

• api/entrypoints/routers.py
• api/entrypoints/worker_queues.py
• api/oss/src/apis/fastapi/sessions/router.py
• api/oss/src/core/channels/commands.py
• api/oss/src/tasks/asyncio/channels/inbox.py
• api/oss/tests/pytest/acceptance/sharing/test_private_session_probe.py
• api/oss/tests/pytest/integration/channels/test_channels_composition_seam.py
• api/oss/tests/pytest/unit/channels/test_channels_commands.py
• api/oss/tests/pytest/unit/sessions/test_cancel_cancels_pending_interactions.py
• api/oss/tests/pytest/unit/sessions/test_insert_paths_require_access.py
• docs/docs/reference/api/set-session-stream.api.mdx
• web/oss/src/components/AgentChatSlice/AgentChatPanel.tsx
• web/packages/agenta-entities/src/session/api/api.ts
• web/packages/agenta-entities/src/session/core/schema.ts
• web/packages/agenta-entities/src/session/index.ts
• web/packages/agenta-entities/tests/unit/session-cancel-stream.test.ts

Files with no reviewable changes: 4

• web/packages/agenta-entities/tests/unit/session-cancel-stream.test.ts
• web/packages/agenta-entities/src/session/core/schema.ts
• web/packages/agenta-entities/src/session/index.ts
• web/packages/agenta-entities/src/session/api/api.ts

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[mmabrouk]

🤖 The AI agent says: About the CodeRabbit nitpick on AgentChatPanel.tsx line 123 (close-time cancel sends no expectedExecutionId or idempotencyKey): we are not fixing this in this PR. The close-time cancel is switched off (CLOSE_CANCELS_RUN = false), so the call never runs today. The PR body already lists this gap under "Before anyone turns on !stop or the tab-close cancel". Whoever turns that path on must pass the tracked execution id and a stable key first.