
A self-healing supervisor that watches another agent through its own traces, catches fabrications before they ship, repairs the root cause, and proves the fix on a held-out set — measured, never asserted.
run_history.jsonlObservability platforms surface the problem and wait for a human to click approve. happyInference closes the loop autonomously — and proves the lift on data it never diagnosed on.
Every span of the supervised agent streams into Arize Phoenix via OpenInference auto-instrumentation.
sentinel/tracing.py
The redactor strikes unverifiable claims before output ships. Every DOI hits the Crossref oracle — fail-closed, so a plausible fake can’t pass.
sentinel/redactor.py
Root cause found by querying the agent’s own failing spans through the Phoenix MCP server — at runtime, not in a dashboard after the fact.
sentinel/diagnostician.py
GEPA-style reflective prompt optimization rewrites the failure away — no weight retraining — reinforced by Reflexion memory across runs.
sentinel/repairer.py
Faithfulness re-measured on a held-out set disjoint from the diagnosis batch. Regressing fixes are blocked — or auto-reverted over A2A.
sentinel/measure.py
Recorded to data/run_history.jsonl on June 9, 2026 — a 10-topic supervision cycle against the deliberately weak research agent. Nothing below is invented; the judges can run the repo.
“The agent’s prompt instructs it to reconstruct plausible DOIs if the exact one cannot be recalled… This encourages the agent to invent DOIs rather than admit uncertainty.”
reconstruct a plausible DOI if the exact one cannot be recalled If you are not highly confident that a DOI is real and published, you MUST leave the source field empty. Never guess, approximate, or fabricate a DOI.
Two real seams into any production agent — whether it cooperates or not. The demo Worker is just the reproducible failure source; the verifier is pluggable.
Connect any standards-compliant A2A agent by URL. happyInference discovers its card, observes, verifies, repairs, teaches — and proves the lift on a disjoint proof set.
# discovery at /.well-known/agent-card.json GET /api/collaborate?agent_url=http://localhost:8010JSON-RPC
message/send · bounded tasks/get polling · auto-revert advisories
For agents whose internals you can’t touch. No SDK, no code change beyond one environment variable — every response verified, the latest adopted advisory injected.
export OPENAI_BASE_URL=\
https://gateway.happyinference.ai/v1
export X_HAPPYINFERENCE_AGENT=acme-support
non-blocking · per-agent policy via X-Sentinel-Agent
Built for the Google Cloud Rapid Agent Hackathon, Arize track — observability data isn’t reviewed after the fact, it is the input to the repair.

Connect an agent and watch a full supervision cycle — catch, diagnose, repair, and the honest before/after.
Open the live console