evals

name	Evals
description	Agent evaluation framework based on Anthropic's best practices. USE WHEN eval, evaluate, test agent, benchmark, verify behavior, regression test, capability test. Includes three grader types (code-based, model-based, human), transcript capture, pass@k/pass^k metrics, and ALGORITHM integration.
implements	Science
science_cycle_time	meso

Customization

Before executing, check for user customizations at: ~/.claude/skills/CORE/USER/SKILLCUSTOMIZATIONS/Evals/

If this directory exists, load and apply any PREFERENCES.md, configurations, or resources found there. These override default behavior. If the directory does not exist, proceed with skill defaults.

🚨 MANDATORY: Voice Notification (REQUIRED BEFORE ANY ACTION)

You MUST send this notification BEFORE doing anything else when this skill is invoked.

1. Send voice notification:

   curl -s -X POST http://localhost:8888/notify \
     -H "Content-Type: application/json" \
     -d '{"message": "Running the WORKFLOWNAME workflow in the Evals skill to ACTION"}' \
     > /dev/null 2>&1 &
   

2. Output text notification:

   Running the **WorkflowName** workflow in the **Evals** skill to ACTION...
   

This is not optional. Execute this curl command immediately upon skill invocation.

Evals - AI Agent Evaluation Framework

Comprehensive agent evaluation system based on Anthropic's "Demystifying Evals for AI Agents" (Jan 2026).

Key differentiator: Evaluates agent workflows (transcripts, tool calls, multi-turn conversations), not just single outputs.

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When to Activate

• "run evals", "test this agent", "evaluate", "check quality", "benchmark"
• "regression test", "capability test"
• Compare agent behaviors across changes
• Validate agent workflows before deployment
• Verify ALGORITHM ISC rows
• Create new evaluation tasks from failures

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Core Concepts

Three Grader Types

Type	Strengths	Weaknesses	Use For
Code-based	Fast, cheap, deterministic, reproducible	Brittle, lacks nuance	Tests, state checks, tool verification
Model-based	Flexible, captures nuance, scalable	Non-deterministic, expensive	Quality rubrics, assertions, comparisons
Human	Gold standard, handles subjectivity	Expensive, slow	Calibration, spot checks, A/B testing

Evaluation Types

Type	Pass Target	Purpose
Capability	~70%	Stretch goals, measuring improvement potential
Regression	~99%	Quality gates, detecting backsliding

Key Metrics

• pass@k: Probability of at least 1 success in k trials (measures capability)
• pass^k: Probability all k trials succeed (measures consistency/reliability)

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Workflow Routing

Trigger	Workflow
"run evals", "evaluate suite"	Run suite via Tools/AlgorithmBridge.ts
"log failure"	Log failure via Tools/FailureToTask.ts log
"convert failures"	Convert to tasks via Tools/FailureToTask.ts convert-all
"create suite"	Create suite via Tools/SuiteManager.ts create
"check saturation"	Check via Tools/SuiteManager.ts check-saturation

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Quick Reference

CLI Commands

# Run an eval suite
bun run ~/.claude/skills/Evals/Tools/AlgorithmBridge.ts -s <suite>

# Log a failure for later conversion
bun run ~/.claude/skills/Evals/Tools/FailureToTask.ts log "description" -c category -s severity

# Convert failures to test tasks
bun run ~/.claude/skills/Evals/Tools/FailureToTask.ts convert-all

# Manage suites
bun run ~/.claude/skills/Evals/Tools/SuiteManager.ts create <name> -t capability -d "description"
bun run ~/.claude/skills/Evals/Tools/SuiteManager.ts list
bun run ~/.claude/skills/Evals/Tools/SuiteManager.ts check-saturation <name>
bun run ~/.claude/skills/Evals/Tools/SuiteManager.ts graduate <name>

ALGORITHM Integration

Evals is a verification method for THE ALGORITHM ISC rows:

# Run eval and update ISC row
bun run ~/.claude/skills/Evals/Tools/AlgorithmBridge.ts -s regression-core -r 3 -u

ISC rows can specify eval verification:

| # | What Ideal Looks Like | Verify |
|---|----------------------|--------|
| 1 | Auth bypass fixed | eval:auth-security |
| 2 | Tests all pass | eval:regression |

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Available Graders

Code-Based (Fast, Deterministic)

Grader	Use Case
string_match	Exact substring matching
regex_match	Pattern matching
binary_tests	Run test files
static_analysis	Lint, type-check, security scan
state_check	Verify system state after execution
tool_calls	Verify specific tools were called

Model-Based (Nuanced)

Grader	Use Case
llm_rubric	Score against detailed rubric
natural_language_assert	Check assertions are true
pairwise_comparison	Compare to reference with position swap

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Domain Patterns

Pre-configured grader stacks for common agent types:

Domain	Primary Graders
coding	binary_tests + static_analysis + tool_calls + llm_rubric
conversational	llm_rubric + natural_language_assert + state_check
research	llm_rubric + natural_language_assert + tool_calls
computer_use	state_check + tool_calls + llm_rubric

See Data/DomainPatterns.yaml for full configurations.

---

Task Schema (YAML)

task:
  id: "fix-auth-bypass_1"
  description: "Fix authentication bypass when password is empty"
  type: regression  # or capability
  domain: coding

  graders:
    - type: binary_tests
      required: [test_empty_pw.py]
      weight: 0.30

    - type: tool_calls
      weight: 0.20
      params:
        sequence: [read_file, edit_file, run_tests]

    - type: llm_rubric
      weight: 0.50
      params:
        rubric: prompts/security_review.md

  trials: 3
  pass_threshold: 0.75

---

Resource Index

Resource	Purpose
Types/index.ts	Core type definitions
Graders/CodeBased/	Deterministic graders
Graders/ModelBased/	LLM-powered graders
Tools/TranscriptCapture.ts	Capture agent trajectories
Tools/TrialRunner.ts	Multi-trial execution with pass@k
Tools/SuiteManager.ts	Suite management and saturation
Tools/FailureToTask.ts	Convert failures to test tasks
Tools/AlgorithmBridge.ts	ALGORITHM integration
Data/DomainPatterns.yaml	Domain-specific grader configs

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Key Principles (from Anthropic)

1. Start with 20-50 real failures - Don't overthink, capture what actually broke
2. Unambiguous tasks - Two experts should reach identical verdicts
3. Balanced problem sets - Test both "should do" AND "should NOT do"
4. Grade outputs, not paths - Don't penalize valid creative solutions
5. Calibrate LLM judges - Against human expert judgment
6. Check transcripts regularly - Verify graders work correctly
7. Monitor saturation - Graduate to regression when hitting 95%+
8. Build infrastructure early - Evals shape how quickly you can adopt new models

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Related

• ALGORITHM: Evals is a verification method
• Science: Evals implements scientific method
• Browser: For visual verification graders