feat(agui): support custom RuntimeContext in AguiAgentAdapter

[ningmeng0503]

Summary

Allow callers to provide a custom RuntimeContext when running an agent through AguiAgentAdapter and AguiRequestProcessor, and let subclasses override the default context construction.

Problem

AguiAgentAdapter.run(RunAgentInput) always built the RuntimeContext internally, so callers could not:

• Pass an existing runtime context that already carries request-scoped metadata.
• Customize the default context via subclassing, because buildRuntimeContext was private.

More importantly, because the adapter owned the context instance, any custom data written by downstream middleware or tools during the run was invisible to the upstream caller. The caller had no way
to read that data back or use it to customize post-run processing.

AguiRequestProcessor had the same limitation: it only exposed process(RunAgentInput, String, String), so AG-UI request handlers could not inject a pre-built context either.

Changes

• Added AguiAgentAdapter.run(RunAgentInput input, RuntimeContext runtimeContext).
  • Uses the supplied context when non-null; otherwise falls back to buildRuntimeContext(input).
  • The caller keeps the same context reference, so values written by middleware/tools are observable after the run.
• Changed AguiAgentAdapter.buildRuntimeContext from private to protected for subclass overrides.
• Added AguiRequestProcessor.process(RunAgentInput, String, String, RuntimeContext).
  • Forwards the context to the adapter; passing null preserves the original behavior.
• Kept the original run(RunAgentInput) and process(RunAgentInput, String, String) methods unchanged for backward compatibility.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[oss-maintainer]

Summary

Clean feature addition — allows callers to inject a custom RuntimeContext into AguiAgentAdapter and AguiRequestProcessor, with proper null-fallback and backward compatibility.

Findings

• [Info] AguiAgentAdapter.java:104 — The null-check + fallback pattern is correct and consistent.
• [Info] AguiRequestProcessor.java:99 — Good that the original 3-arg method is preserved as a delegate.
• [Info] Tests cover all three paths (custom context, null fallback, subclass override) — well done.

Verdict

Straightforward, well-tested, fully backward compatible. LGTM.

---

Automated review by github-manager