fix(security): reject API key auth when LANGGRAPH_API_KEY is not configured

[NP-compete]

Closes #234

Summary

• Change validate_api_key() to raise AuthError(status_code=500) when LANGGRAPH_API_KEY is empty, instead of returning True for any key
• Update test test_accepts_when_no_key_configured to test_raises_when_no_key_configured, verifying the 500 status code

Test plan

• test_raises_when_no_key_configured: verifies AuthError is raised with status 500 when API key is not set
• test_accepts_correct_key: still passes with a configured key
• test_rejects_wrong_key: still rejects incorrect keys
• All 13 middleware tests pass
• Pre-commit hooks pass (ruff, mypy, bandit)

[coderabbitai]

Walkthrough

When API-key authentication is enabled without LANGGRAPH_API_KEY, validate_api_key now raises a 500 AuthError instead of accepting any key. The unit test now verifies the error message and status code.

Suggested reviewers: anish701

Merge Risk: 🔵 Low · up to e6541

The change makes API-key authentication fail closed when LANGGRAPH_API_KEY is not configured. Merge readiness has one bounded issue remaining: a localized Ruff lint violation should be fixed or explicitly accepted.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% 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 clearly identifies the security fix for rejecting API-key authentication when LANGGRAPH_API_KEY is not configured.
Description check	✅ Passed	The description accurately explains the authentication change, linked issue, test updates, and verification results.
Linked Issues check	✅ Passed	The changes satisfy issue #234 by raising AuthError with status 500 when LANGGRAPH_API_KEY is not configured.
Out of Scope Changes check	✅ Passed	The changes are limited to the API-key validation behavior and its corresponding unit test, with no unrelated code changes.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

🚀 Post-Merge Actions

• Update changelog

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[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In `@deep_agent/aegra/middleware.py`:
- Around line 40-43: Update AuthError and its call site in the authentication
middleware to move the long LANGGRAPH_API_KEY message into the exception class,
allowing the raise to pass only the appropriate structured data while preserving
the existing 500 status and resulting error message.

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Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
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📥 Commits

Reviewing files that changed from the base of the PR and between 67fddb8 and e654178.

📒 Files selected for processing (2)

• deep_agent/aegra/middleware.py
• tests/unit/aegra/test_middleware.py

🔗 Linked repositories identified

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

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[vishnusrichand]

LGTM