Skillgrade

The easiest way to evaluate your Agent Skills. Tests that AI agents correctly discover and use your skills.

See examples/ — superlint (simple) and angular-modern (TypeScript grader).

Quick Start

Prerequisites: Node.js 20+, Docker

npm i -g skillgrade

1. Initialize — go to your skill directory (must have SKILL.md) and scaffold:

cd my-skill/
GEMINI_API_KEY=your-key skillgrade init    # or ANTHROPIC_API_KEY / OPENAI_API_KEY
# Use --force to overwrite an existing eval.yaml

Generates eval.yaml with AI-powered tasks and graders. Without an API key, creates a well-commented template.

2. Edit — customize eval.yaml for your skill (see eval.yaml Reference).

3. Run:

GEMINI_API_KEY=your-key skillgrade --smoke

The agent is auto-detected from your API key: GEMINI_API_KEY → Gemini, ANTHROPIC_API_KEY → Claude, OPENAI_API_KEY → Codex. Override with --agent=claude.

4. Review:

skillgrade preview          # CLI report
skillgrade preview browser  # web UI → http://localhost:3847

Reports are saved to $TMPDIR/skillgrade/<skill-name>/results/. Override with --output=DIR.

Presets

Options

eval.yaml Reference

version: "1"

# Optional: explicit path to skill directory (defaults to auto-detecting SKILL.md)
# skill: path/to/my-skill

defaults:
  agent: gemini          # gemini | claude | codex | acp | opencode | command
  provider: docker       # docker | local
  trials: 5
  timeout: 300           # seconds
  threshold: 0.8         # for --ci mode
  grader_model: gemini-3-flash-preview  # default LLM grader model
  grader_provider: gemini               # default LLM grader provider: gemini | anthropic | openai
  command: node mycli.js # command to run when agent is 'command' (see Custom Command Agent)
  acp:                   # ACP agent configuration (optional)
    command: gemini --acp  # command to start ACP-compatible agent
    env:                  # optional environment variables
      DEBUG: "1"
  docker:
    base: node:20-slim
    setup: |             # extra commands run during image build
      apt-get update && apt-get install -y jq
  environment:           # container resource limits
    cpus: 2
    memory_mb: 2048

tasks:
  - name: fix-linting-errors
    instruction: |
      Use the superlint tool to fix coding standard violations in app.js.

    workspace:                           # files copied into the container
      - src: fixtures/broken-app.js
        dest: app.js
      - src: bin/superlint
        dest: /usr/local/bin/superlint
        chmod: "+x"

    graders:
      - type: deterministic
        setup: npm install typescript    # grader-specific deps (optional)
        run: npx ts-node graders/check.ts
        weight: 0.7
      - type: llm_rubric
        rubric: |
          Did the agent follow the check → fix → verify workflow?
        provider: gemini                 # optional: gemini (default) | anthropic | openai
        model: gemini-3.5-flash          # optional model override
        weight: 0.3

    # Per-task overrides (optional)
    agent: claude
    grader_provider: anthropic   # override default LLM grader provider
    trials: 10
    timeout: 600

String values (instruction, rubric, run) support file references — if the value is a valid file path, its contents are read automatically:

instruction: instructions/fix-linting.md
rubric: rubrics/workflow-quality.md

Graders

Deterministic

Runs a command and parses JSON from stdout:

- type: deterministic
  run: bash graders/check.sh
  weight: 0.7

Output format:

{
  "score": 0.67,
  "details": "2/3 checks passed",
  "checks": [
    {"name": "file-created", "passed": true, "message": "Output file exists"},
    {"name": "content-correct", "passed": false, "message": "Missing expected output"}
  ]
}

score (0.0–1.0) and details are required. checks is optional.

Bash example:

#!/bin/bash
passed=0; total=2
c1_pass=false c1_msg="File missing"
c2_pass=false c2_msg="Content wrong"

if test -f output.txt; then
  passed=$((passed + 1)); c1_pass=true; c1_msg="File exists"
fi
if grep -q "expected" output.txt 2>/dev/null; then
  passed=$((passed + 1)); c2_pass=true; c2_msg="Content correct"
fi

score=$(awk "BEGIN {printf \"%.2f\", $passed/$total}")
echo "{\"score\":$score,\"details\":\"$passed/$total passed\",\"checks\":[{\"name\":\"file\",\"passed\":$c1_pass,\"message\":\"$c1_msg\"},{\"name\":\"content\",\"passed\":$c2_pass,\"message\":\"$c2_msg\"}]}"

Use awk for arithmetic — bc is not available in node:20-slim.

LLM Rubric

Evaluates the agent's session transcript against qualitative criteria:

- type: llm_rubric
  rubric: |
    Workflow Compliance (0-0.5):
    - Did the agent follow the mandatory 3-step workflow?

    Efficiency (0-0.5):
    - Completed in ≤5 commands?
  weight: 0.3
  provider: gemini           # gemini (default) | anthropic | openai
  model: gemini-2.0-flash    # optional, auto-detected from API key

The provider field selects which LLM API to call:

ANTHROPIC_BASE_URL and OPENAI_BASE_URL enable custom/self-hosted endpoints (Ollama, vLLM, etc.).

Combining Graders

graders:
  - type: deterministic
    run: bash graders/check.sh
    weight: 0.7      # 70% — did it work?
  - type: llm_rubric
    rubric: rubrics/quality.md
    weight: 0.3      # 30% — was the approach good?

Final reward = Σ (grader_score × weight) / Σ weight

CI Integration

Use --provider=local in CI — the runner is already an ephemeral sandbox, so Docker adds overhead without benefit.

# .github/workflows/skillgrade.yml
- run: |
    npm i -g skillgrade
    cd skills/superlint
    GEMINI_API_KEY=${{ secrets.GEMINI_API_KEY }} skillgrade --regression --ci --provider=local

Exits with code 1 if pass rate falls below --threshold (default: 0.8).

Tip: Use docker (the default) for local development to protect your machine. In CI, local is faster and simpler.

Environment Variables

Variables are also loaded from .env in the skill directory. Shell values override .env. All values are redacted from persisted session logs.

Custom Command Agent

Bring your own agent. The built-in adapters (gemini, claude, codex, ...) cover the popular CLIs, but you can point skillgrade at any command — a custom script, a [deepagents](https://github.com/langchain-ai/deepagen