Add health-aware routing and content-safe observability

[Deathcharge]

Outcome

Adds content-safe observability and cross-request provider health without adding exporters, persistence, or gateway infrastructure.

• sync/async on_attempt callback receives only immutable sanitized Attempt metadata
• observer failures are isolated while cancellation still propagates
• transient failures maintain provider-local health and bounded cooldown state
• cooling routes move behind healthy routes but remain last-resort fallbacks
• explicit provider= selection can probe immediately and successful probes reset health
• exposes content-free ProviderHealth snapshots and environment configuration

Verification

• python -m ruff format --check .
• python -m ruff check .
• python -m mypy unified_llm tests examples
• python -m pytest --cov=unified_llm --cov-report=term-missing (118 passed, 94.73% coverage)
• python examples/observability.py
• python -m build --no-isolation

Rollback

Revert commit e9cd70b; bounded routing and both HTTP adapters remain independently available.

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Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 7d592b3a-8157-481d-9217-ef5223ebcb8c

📥 Commits

Reviewing files that changed from the base of the PR and between e9cd70b and 1107a17.

📒 Files selected for processing (1)

• .env.example

Summary by CodeRabbit

• New Features

  • Added provider health monitoring with configurable failure thresholds and cooldown periods.
  • Temporarily deprioritizes repeatedly failing providers while preserving fallback behavior.
  • Added provider health inspection and sanitized attempt notifications for observability.
  • Added environment-variable configuration for health settings.
  • Assistant responses can now include tool calls for function continuation.

• Documentation

  • Updated API, architecture, README, changelog, roadmap, and examples with health and observability guidance.

• Tests

  • Added coverage for cooldown, recovery, configuration validation, callback isolation, and route behavior.

Walkthrough

UnifiedLLM now tracks provider health, applies transient-failure cooldowns, exposes health snapshots, and emits sanitized attempt callbacks. Configuration supports constructor and environment values. Tests, documentation, exports, and an observability example cover the new behavior.

Changes

Provider health and attempt observability

Layer / File(s)	Summary
Health contracts and configuration unified_llm/unified_llm.py, unified_llm/__init__.py, .env.example, tests/test_configuration.py, tests/test_router.py, docs/API.md, README.md	UnifiedLLM adds health configuration, ProviderHealth, AttemptHook, environment parsing, health inspection, validation, and public exports. API documentation also describes tool-call assistant messages.
Cooldown routing and recovery unified_llm/unified_llm.py, tests/test_health_observability.py, README.md, docs/ARCHITECTURE.md, CHANGELOG.md, ROADMAP.md	Retryable failures increment provider health, open cooldowns, reorder routes, preserve fallback, support explicit probing, and reset after recovery.
Attempt observation and example unified_llm/unified_llm.py, tests/test_health_observability.py, examples/observability.py, README.md, docs/API.md	Attempts report provider outcomes through synchronous or asynchronous callbacks. Callback failures are isolated, cancellation is preserved, and the example aggregates sanitized results.

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

Sequence Diagram(s)

sequenceDiagram
  participant Application
  participant UnifiedLLM
  participant Provider
  participant BackupProvider
  participant on_attempt
  Application->>UnifiedLLM: submit generation request
  UnifiedLLM->>Provider: execute route attempt
  Provider-->>UnifiedLLM: return transient failure
  UnifiedLLM->>on_attempt: emit sanitized Attempt
  UnifiedLLM->>BackupProvider: execute fallback route
  BackupProvider-->>UnifiedLLM: return successful response
  UnifiedLLM->>on_attempt: emit successful Attempt
  UnifiedLLM-->>Application: return response

Loading

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 17.86% 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
Description check	✅ Passed	The description clearly explains the health-aware routing and content-safe observability changes.
Title check	✅ Passed	The title clearly and concisely summarizes the pull request's main routing and observability changes.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/health-observability

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Actionable comments posted: 1

🤖 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.

Inline comments:
In @.env.example:
- Around line 16-17: Reorder the environment configuration keys so
UNIFIED_LLM_HEALTH_COOLDOWN appears before UNIFIED_LLM_HEALTH_FAILURE_THRESHOLD,
and place both health keys before UNIFIED_LLM_MAX_ATTEMPTS_PER_ROUTE in the
.env.example configuration.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 2649c9c7-64fc-4364-b108-4697e48f8a2a

📥 Commits

Reviewing files that changed from the base of the PR and between 775aecb and e9cd70b.

📒 Files selected for processing (12)

• .env.example
• CHANGELOG.md
• README.md
• ROADMAP.md
• docs/API.md
• docs/ARCHITECTURE.md
• examples/observability.py
• tests/test_configuration.py
• tests/test_health_observability.py
• tests/test_router.py
• unified_llm/__init__.py
• unified_llm/unified_llm.py