# nsega

- **Event:** [Claude Build Day](https://cerebralvalley.ai/e/claude-startups-build-day)
- **When:** Sat, Jun 13 at 9:00 AM – 10:00 PM (PDT)
- **Where:** San Francisco, CA
- **Team:** [Naoki Sega](https://cerebralvalley.ai/u/nsega)
- **GitHub:** https://github.com/nsega/routecause
- **Website:** https://clarity-debug-seal-wearing.trycloudflare.com/
- **Demo video:** https://youtu.be/XXl5l0c5GmM
- **Gallery:** https://cerebralvalley.ai/e/claude-startups-build-day/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/claude-startups-build-day/hackathon/gallery/35

The project "RouteCause" is an autonomous diagnostics agent for LLM inference infrastructure on Kubernetes. When shared model-serving degrades, it investigates and hands platform/infra engineers a root-cause report with a concrete fix — turning a slow, manual, four-source correlation into one automated run.

The problem: LLM serving on Kubernetes (Gateway API Inference Extension / InferencePool / Endpoint Picker (EPP) scheduling, now llm-d Router) usually degrades because of routing and scheduling misconfiguration, not capacity. Symptoms — P95 Time to First Token(TTFT)/latency breaching SLO, queue depth piling on some replicas while others idle, KV-cache saturation, prefix-cache hit-rate collapse after a rollout — require cross-referencing gateway/EPP metrics, scheduler config, endpoint health, and recent manifest diffs. When you're paged on an SLO breach, that correlation is slow and error-prone.

How it works: an SLO breach (or a manual POST /diagnose) triggers the agent. Context-isolated subagents each pull one evidence source — Prometheus metrics, the EPP ConfigMap, and live cluster/endpoint state — and form hypotheses independently, so no single context owns all the evidence. Each surviving hypothesis then faces an independent verifier subagent whose job is to falsify it. The output is a single root-cause report: the diagnosis, ≥2 pieces of cross-source evidence, and a fix as a manifest diff or "kubectl patch" validated with "kubectl apply --dry-run=server". It targets three fault classes — EPP scorer-weight misconfig, an unhealthy endpoint left in rotation, and prefix-cache routing silently disabled by a rollout. Stretch goal: apply the fix and confirm recovery against the SLO.

Scope and provenance: the agent was built today in "nsega/routecause". The Kubernetes test environment (kind cluster + llm-d Router + InferencePool + simulated backends + fault injection) is a pre-existing project, "nsega/inference-lab", brought in as scaffolding and referenced, not rebuilt — see PROVENANCE.md for the build-today vs. brought-in boundary. The deliverable is the agent and its reports; there is no metrics dashboard.

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Markdown version of https://cerebralvalley.ai/e/claude-startups-build-day/hackathon/gallery/35. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt