# Trace Harness Launch Failure > Empty session traces mean launch failure, not agent behavior — verify api_call_count/tool_call_count and stdout.txt before analyzing. - Skill: `ashutoshsinghpr7/trace-harness-launch-failure` (Agent Skill) - Install (CLI): `npx skillmds@latest add ashutoshsinghpr7/trace-harness-launch-failure` - Raw SKILL.md: https://api.skillmd.com/api/skills/ashutoshsinghpr7/trace-harness-launch-failure/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - License: MIT - Author: ashutoshsinghpr7 (https://skillmd.com/u/ashutoshsinghpr7) - Updated: 2026-09-22 - Page: https://skillmd.com/skills/ashutoshsinghpr7/trace-harness-launch-failure --- # Trace Harness Launch Failure — empty sessions, scores from deliverables ## Problem Four training traces contain ONLY the initial task prompt: 1 message, 0 tool calls, 0 API calls, ~1 s duration. No agent reasoning, tool call, or final answer anywhere — yet `meta.json` carries scores (0.0 / 1.0). ## Root cause Every recorded run died at launch: `runs//stdout.txt` shows "HTTP 400: default is not a valid model ID" — the harness sent an invalid model ID instead of the configured model, so the agent never executed. The scores were produced by grading the on-disk deliverables against the exact-match graders in tasks.json — not from any recorded agent behavior. ## Fix - Before analyzing "agent behavior", verify the session actually ran: check `api_call_count` / `tool_call_count` / `message_count` in the trace and stdout.txt for launch errors. Empty trace == no behavioral evidence. - When traces are empty, reconstruct ground truth by diffing the on-disk deliverable against the task's grader expectation (`tasks.json` → `grader.expected`), and read spec.md + input data to explain the score. - Treat prior-iteration behavioral claims as unverifiable until new traces confirm them; flag evidence status in the run log. - Surface the harness bug so the runner is fixed before the next iteration, otherwise every proposal rests on inferred data.