eval-diagnose

eval-diagnose is a skill for Claude Code, Codex from Galileo-Agent-Labs/eval-engineer. It costs 41 tokens per session (584 once invoked), scanned A, original, MIT.

A troubleshooting guide for finding why an AI application's behavior or evaluation result failed, worsened, or became unsafe. It uses Galileo evidence such as traces, sessions, logs, tool calls, and metric results rather than guesses from source code alone.

In plain words
What is it for?
Use it to diagnose failed evaluations, inspect AI execution evidence, identify the failing metric or contract, classify the likely fix area, and write an evidence-based diagnosis with a limited repair plan.
Why use it?
It connects observed failures to the part of the system that may need changing, such as a prompt, tool, retriever, ranking method, safety rule, metric, dataset, or software connection.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to diagnose failed evaluations, inspect AI execution evidence, identify the failing metric or contract, classify the likely fix area, and write an evidence-based diagnosis with a limited repair plan.

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Install with agentmods
npx agentmods add skills/galileo-agent-labs/eval-engineer/eval-diagnose
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Galileo-Agent-Labs/eval-engineer --skill eval-diagnose
Clone the repo
git clone --depth 1 https://github.com/Galileo-Agent-Labs/eval-engineer

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for eval-diagnose

README.md
[![agentmods](https://agentmods.dev/badge/skills/galileo-agent-labs/eval-engineer/eval-diagnose.svg)](https://agentmods.dev/skills/galileo-agent-labs/eval-engineer/eval-diagnose)
Your own site
<a href="https://agentmods.dev/skills/galileo-agent-labs/eval-engineer/eval-diagnose"><img src="https://agentmods.dev/badge/skills/galileo-agent-labs/eval-engineer/eval-diagnose.svg" alt="Measured on agentmods" height="20"></a>
Per session 41 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 584 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00041 $0.00584
Opus 5 $0.00020 $0.00292
Sonnet 5 $0.00008 $0.00117
Haiku 4.5 $0.00004 $0.00058

Measured 8d ago against content hash 40c50e7e3f67, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

eval-diagnose scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/eval-diagnose/SKILL.md · 62 lines

How it starts

The opening of the file, as written. The whole thing — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Eval Diagnose

Use this skill for evidence-backed RCA once a packet, URL-derived evidence, or trace/session/log-stream context is available.

Required Reference

Use skills/eval-engineer/references/rca-recipe.md, skills/eval-engineer/references/debug-packets.md, skills/eval-engineer/references/evidence-provenance.md, and skills/eval-engineer/assets/diagnosis-template.md.

Do

  • Start from fetched evidence, not source-code guesses.
  • Name the failing metric contract and what it proves.
  • Label hosted Galileo evidence separately from local deterministic packets before making metric or score claims.
  • Inspect traces, spans, sessions, tool calls, retrieval context, and scorer status to classify the fix surface.
  • Classify the fix surface: prompt, tool schema, adapter, retriever, ranker, guardrail, metric, dataset, or SDK wiring.
  • Write diagnosis and bounded fix plan only when evidence supports it.
  • Honor read-only requests. If the user says read-only, dry run, no edits, or "do not edit files", do not write .galileo/ artifacts. Return the RCA inline and include a short "Would write" list for any suggested artifact paths.

Gotchas

  • Fetched debug packets are the RCA source of truth when scorer jobs are still settling or runner output disagrees with fetched metrics.
  • A prompt diff, local score, or code diff is not proof of improvement without before/after Galileo evidence.
  • Bare correctness or factuality can be a smoke test only. Prefer the metric contract tied to the case risk.
  • Safe final wording is not enough for source-authority cases if unsafe or forbidden retrieved context entered the task surface.

Validation Loop

Before finalizing:

  1. Run python3 skills/eval-engineer/scripts/summarize_debug_packet.py <packet> unless a compact summary is already available.
  2. Check that every RCA claim names supporting metric, trace, span, session, experiment, dataset, or log-stream evidence.
  3. Confirm the fix surface is bounded and allowed by .galileo/config.yml.
  4. If any claim lacks evidence, downgrade it to a hypothesis or route to /eval-fetch or /eval-measure.

Read the full file on GitHub · 62 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 62 lines · 41 tokens per session scan A 40c50e7e3f67

Subscribe to this mod's changes

eval-diagnose is a skill published in the GitHub repository Galileo-Agent-Labs/eval-engineer (41 stars, last pushed 26d ago), licensed MIT. It adds 41 tokens to every session and 584 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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