feat: emit LangGraph interrupts as first-class SSE events

[joewood-redhat]

Summary

• Emit LangGraph __interrupt__ updates as typed SSE events (type: "interrupt") instead of wrapping them in synthetic AIMessage payloads.
• Include run/thread/session/user/trace metadata on interrupt events for client correlation.
• Parse JSON-string interrupt payloads (e.g. MCP auth mcp_auth_required) so clients can use value.type without an extra JSON.parse.

Motivation: discover-agent UI needs to detect MCP auth interrupts and show connect flows; message-shaped interrupts were easy to miss or mishandle in the stream pipeline.

Test plan

• uv run pytest tests/unit/streaming/test_streaming.py -q
• Trigger an MCP auth interrupt in a local run — SSE stream includes type: "interrupt" with parsed JSON payload
• Confirm regular assistant message streaming is unchanged for non-interrupt runs

Made with Cursor

Closes #198

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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• tests/unit/streaming/test_streaming.py

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• redhat-data-and-ai/template-mcp (manual)
• redhat-data-and-ai/template-ui (manual)

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Walkthrough

The streaming handler normalizes JSON-string interrupt payloads and emits first-class interrupt SSE events with thread and run metadata. Interrupt events are returned separately from formatted messages. Existing message overwrite, deduplication, and tracking behavior remains in place. Unit tests verify event structure and MCP authentication payload parsing.

Suggested reviewers: np-compete

Merge Risk: 🔵 Low · up to 1bd0f

The new interrupt SSE contract includes correlation metadata, but the current tests do not verify every required field, leaving a bounded risk that clients could receive incomplete correlation data; merge is reasonable with explicit owner follow-up to strengthen the test.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the primary change: emitting LangGraph interrupts as first-class SSE events.
Description check	✅ Passed	The description directly explains the interrupt SSE changes, metadata, payload parsing, motivation, and testing.
Linked Issues check	✅ Passed	The implementation and tests satisfy issue #198 by emitting typed interrupt SSE events with parsed payloads and correlation metadata.
Out of Scope Changes check	✅ Passed	The changes remain within issue #198 and cover interrupt handling, payload normalization, metadata, and related tests.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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• Update changelog

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[joewood-redhat]

CI follow-up: Linked issue #198. @redhat-data-and-ai/template-agent-maintainers — please assign @joewood-redhat to #198 (fork contributors cannot self-assign on this repo). DCO sign-off added to all commits.

[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In `@tests/unit/streaming/test_streaming.py`:
- Around line 561-564: Extend the interrupt event assertions in the streaming
test to also validate the required correlation fields trace_id, session_id, and
user_id against their corresponding values in stream_context, while preserving
the existing type, content, thread_id, and run_id checks.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 6df1b0e9-e4d5-4e2f-8b7b-0bc59d8e3ea3

📥 Commits

Reviewing files that changed from the base of the PR and between 17a3d72 and b814086.

📒 Files selected for processing (2)

• deep_agent/src/streaming/handlers.py
• tests/unit/streaming/test_streaming.py

🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

• redhat-data-and-ai/template-mcp (manual)
• redhat-data-and-ai/template-ui (manual)

[joewood-redhat]

Review feedback addressed in 1d0d49a — interrupt correlation field assertions plus malformed JSON and raw-interrupt coverage tests.

@redhat-data-and-ai/template-agent-maintainers — please assign @joewood-redhat to #198 so Check Issue Link CI passes (fork contributors cannot self-assign).

[ipbabble]

Nice! LGTM.