fix(plugin): route registration banner to stderr

[WilliamK112]

Summary

Routes the NemoClaw plugin registration banner directly to stderr instead of api.logger.info, so non-JSON nemoclaw <sandbox> agent passthrough stdout remains reserved for the agent reply.

Related Issue

Fixes #5654

Changes

• Writes the registration banner with process.stderr.write.
• Updates plugin registration tests to capture stderr.
• Adds a regression assertion that the banner no longer uses api.logger.info.

Type of Change

• Code change for a new feature, bug fix, or refactor.
• Code change with doc updates.
• Doc only. Prose changes without code sample modifications.
• Doc only. Includes code sample changes.

Testing

• npx prek run --all-files passes (or equivalently make check).
• npm test passes.
• make docs builds without warnings. (for doc-only changes)

Targeted checks run:

• cd nemoclaw && npm test -- src/register.test.ts
• cd nemoclaw && npm run lint -- src/index.ts src/register.test.ts
• cd nemoclaw && npm run build

Checklist

General

• I have read and followed the contributing guide.
• I have read and followed the style guide. (for doc-only changes)

Code Changes

• Tests added or updated for new or changed behavior.
• No secrets, API keys, or credentials committed.
• Doc pages updated for any user-facing behavior changes, or no doc update needed because this restores the expected stdout/stderr contract.

Signed-off-by: WilliamK112 164879897+WilliamK112@users.noreply.github.com

Summary by CodeRabbit

• Refactor

  • Updated the plugin startup banner to write directly to standard error, improving reliability of banner rendering across environments.

• Tests

  • Revised registration-banner tests to validate output captured from standard error instead of logger calls, including coverage for model selection and fallback behavior.

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[coderabbitai]

📝 Walkthrough

Walkthrough

The plugin registration startup banner in register() is changed from emitting via api.logger.info to writing directly to process.stderr. Corresponding tests replace logger-based assertions with a process.stderr.write spy and updated banner content checks.

Changes

Banner output routed to stderr

Layer / File(s)	Summary
Banner redirected to process.stderr nemoclaw/src/index.ts	renderBox(bannerLines) output and surrounding blank lines are now emitted via process.stderr.write(line + '\n') instead of api.logger.info(...).
Tests updated for stderr assertions nemoclaw/src/register.test.ts	Adds afterEach import and stderr capture helpers (mockStderrWrite, stderrOutput); wires stderr spying into beforeEach for the plugin registration and before_tool_call suites; replaces prior api.logger.info assertions with stderrOutput() checks for banner lines ("NemoClaw registered", "Endpoint", "Provider", "Model"); adds afterEach cleanup via vi.restoreAllMocks().

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~4 minutes

Poem

🐰 Hop hop, the banner took a wrong turn,
It cluttered stdout — quite a concern!
Now stderr's the home for the plugin's big shout,
No more init box leaking the agent reply out.
The rabbit grins wide: clean pipes all around! 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title concisely and accurately summarizes the main change: redirecting the registration banner output to stderr instead of stdout.
Linked Issues check	✅ Passed	The PR directly addresses issue #5654 by routing the registration banner to stderr instead of stdout, preventing stdout pollution in non-JSON mode.
Out of Scope Changes check	✅ Passed	All changes are directly related to the objective of routing the registration banner to stderr; no unrelated modifications are present.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[coderabbitai]

🧹 Nitpick comments (1)

nemoclaw/src/register.test.ts (1)

81-81: 🩺 Stability & Availability | 🔵 Trivial | ⚡ Quick win

Restore process.stderr.write after each test to prevent cross-test bleed.

vi.clearAllMocks() resets call history but does not restore spied implementations. Adding afterEach(() => vi.restoreAllMocks()) (or restoring stderrWrite directly) avoids leakage into other suites.

Suggested patch

 describe("plugin registration", () => {
   beforeEach(() => {
     vi.clearAllMocks();
     mockStderrWrite();
   });
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
@@
 describe("before_tool_call secret scanner hook (`#1233`)", () => {
   beforeEach(() => {
     vi.clearAllMocks();
     mockStderrWrite();
   });
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });

Also applies to: 209-210

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@nemoclaw/src/register.test.ts` at line 81, The mockStderrWrite function call
spies on process.stderr.write but the spy is not being restored between tests,
which can cause state to leak from one test to another. Add an afterEach hook in
the test suite that calls vi.restoreAllMocks() to properly restore the original
implementations of spied functions after each test completes, ensuring no
cross-test contamination occurs.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@nemoclaw/src/register.test.ts`:
- Line 81: The mockStderrWrite function call spies on process.stderr.write but
the spy is not being restored between tests, which can cause state to leak from
one test to another. Add an afterEach hook in the test suite that calls
vi.restoreAllMocks() to properly restore the original implementations of spied
functions after each test completes, ensuring no cross-test contamination
occurs.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: 7e1e9707-82ef-4363-87d5-7e7005ad92e2

📥 Commits

Reviewing files that changed from the base of the PR and between a9f31e4 and daad68c.

📒 Files selected for processing (2)

• nemoclaw/src/index.ts
• nemoclaw/src/register.test.ts

[wscurran]

✨ Thanks for routing the plugin registration banner to stderr to keep non-JSON agent passthrough stdout clean. This proposes a way to write the banner via process.stderr.write and updates plugin registration tests to capture stderr.

---

Related open issues:

• #5654 [Ubuntu 26.04][CLI&UX] nemoclaw agent writes "[plugins] NemoClaw registered" init box to stdout in non-json mode, polluting piped output

[cjagwani]

Reviewed the exact head after the shared-test rerun: the registration banner is redirected to stderr, stdout remains machine-readable, and the focused regression coverage plus full CI are green.

[cjagwani]

Superseded by current-main replacement #6480, which preserves the banner-to-stderr fix, adds the non-JSON passthrough boundary coverage, and is green/approved at exact head 6b82a4d. Closing this stale duplicate so the release queue has one merge candidate.