evalyn-analyze

A guide for analyzing Evalyn evaluation runs, which are recorded tests of an agent's performance. It covers summaries, failure groups, comparisons, trends, and recommended next steps.

In plain words
What is it for?
Use it to inspect the latest run, review metric scores, find patterns and anomalies, compare two runs, track project trends, and choose follow-up actions.
Why use it?
It turns pass rates and failures into concrete findings instead of leaving developers to inspect runs manually. It also helps identify changes between evaluations.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/shihongdev/evalyn/evalyn-analyze
Any agent
npx skills add shihongDev/evalyn --skill evalyn-analyze
Clone the repo
git clone --depth 1 https://github.com/shihongDev/evalyn

Made for: Claude Code, Codex.

Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 720 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00023 $0.00720
Opus 5 $0.00012 $0.00360
Sonnet 5 $0.00005 $0.00144
Haiku 4.5 $0.00002 $0.00072

Measured 2d ago against content hash bcd62c163562, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

evalyn-analyze 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 2d 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.

sdk/skills/evalyn-analyze/SKILL.md · 101 lines

How it starts

The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.

evalyn-analyze

Overview

Analyze evaluation results progressively: summary, insights, failure clustering, and trend analysis. Interpret findings and recommend next actions based on pass rates.

Pre-flight

Verify evaluation runs exist:

evalyn list-runs --limit 3

If no runs: "You need to run an evaluation first. Invoke evalyn-eval."

Identify the latest run ID from the output.

Step 1: Metric Summary

evalyn analyze --run <run-id>

This shows:

  • Per-metric pass rates and average scores
  • Key findings (highest/lowest performing metrics)
  • Overall health rating (GOOD/MODERATE/POOR)

You can also use short IDs (first 8 characters of run ID).

Step 2: Deep Insights

evalyn insights --run <run-id>

Provides diagnostic and prescriptive analysis:

  • Metric correlations (which metrics move together)
  • Anomaly detection
  • Actionable recommendations

Step 3: Compare and Trend

If multiple runs exist (check evalyn list-runs output):

evalyn compare --run1 <previous-run-id> --run2 <latest-run-id>

For longer history across all runs in a dataset:

evalyn trend --project <project-name>

Note: use --run1 and --run2 flags for compare, not positional arguments.

Step 4: Investigate Failures

If any metric has pass rate below 90%:

evalyn cluster-failures --run-id <run-id>

This clusters failed items by failure reason, revealing patterns (e.g., "all failures involve long inputs" or "failures cluster around a specific topic").

Step 5: Interpret and Recommend

Based on the results, recommend next action:

Overall Pass Rate Interpretation Recommendation
Above 95% Agent performing well Consider evalyn simulate --dataset <path> --modes similar,outlier for edge case testing. Export report: evalyn export --run <id> --format html
80-95% Moderate issues Review failing items. Could be agent issues OR judge misalignment. Consider invoking evalyn-calibrate to verify judges are accurate.
Below 80% Significant issues Invoke evalyn-calibrate to annotate items and check if judges agree with human expectations. Fix agent if judges are correct.

Read the full file on GitHub · 101 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. 2d ago First seen · 101 lines · 23 tokens per session scan A bcd62c163562

Subscribe to this mod's changes

evalyn-analyze is a skill published in the GitHub repository shihongDev/evalyn (257 stars, last pushed 3mo ago), licensed MIT. It adds 23 tokens to every session and 720 once invoked, about $0.0001 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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