JSON Schemas

This document defines the JSON schemas used by skill-creator. Use it to navigate the topic and choose relevant methods, papers or tools.

Editorial note: curated source snapshot published by Collider.club under the MIT License. Source attribution is preserved in the front matter.

Source snapshot

JSON Schemas

This document defines the JSON schemas used by skill-creator.

evals.json

Defines the evals for a skill. Located at evals/evals.json within the skill directory.

{
  "skill_name": "example-skill",
  "evals": [
    {
      "id": 1,
      "prompt": "User's example prompt",
      "expected_output": "Description of expected result",
      "files": ["evals/files/sample1.pdf"],
      "expectations": [
        "The output includes X",
        "The skill used script Y"
      ]
    }
  ]
}

Fields:

• skill_name: Name matching the skill's frontmatter
• evals[].id: Unique integer identifier
• evals[].prompt: The task to execute
• evals[].expected_output: Human-readable description of success
• evals[].files: Optional list of input file paths (relative to skill root)
• evals[].expectations: List of verifiable statements

history.json

Tracks version progression in Improve mode. Located at workspace root.

{
  "started_at": "2026-01-15T10:30:00Z",
  "skill_name": "pdf",
  "current_best": "v2",
  "iterations": [
    {
      "version": "v0",
      "parent": null,
      "expectation_pass_rate": 0.65,
      "grading_result": "baseline",
      "is_current_best": false
    },
    {
      "version": "v1",
      "parent": "v0",
      "expectation_pass_rate": 0.75,
      "grading_result": "won",
      "is_current_best": false
    },
    {
      "version": "v2",
      "parent": "v1",
      "expectation_pass_rate": 0.85,
      "grading_result": "won",
      "is_current_best": true
    }
  ]
}

Fields:

• started_at: ISO timestamp of when improvement started
• skill_name: Name of the skill being improved
• current_best: Version identifier of the best performer
• iterations[].version: Version identifier (v0, v1, ...)
• iterations[].parent: Parent version this was derived from
• iterations[].expectation_pass_rate: Pass rate from grading
• iterations[].grading_result: "baseline", "won", "lost", or "tie"
• iterations[].is_current_best: Whether this is the current best version

grading.json

Output from the grader agent. Located at <run-dir>/grading.json.

{
  "expectations": [
    {
      "text": "The output includes the name 'John Smith'",
      "passed": true,
      "evidence": "Found in transcript Step 3: 'Extracted names: John Smith, Sarah Johnson'"
    },
    {
      "text": "The spreadsheet has a SUM formula in cell B10",
      "passed": false,
      "evidence": "No spreadsheet was created. The output was a text file."
    }
  ],
  "summary": {
    "passed": 2,
    "failed": 1,
    "total": 3,
    "pass_rate": 0.67
  },
  "execution_metrics": {
    "tool_calls": {
      "Read": 5,
      "Write": 2,
      "Bash": 8
    },
    "total_tool_calls": 15,
    "total_steps": 6,
    "errors_encountered": 0,
    "output_chars": 12450,
    "transcript_chars": 3200
  },
  "timing": {
    "executor_duration_seconds": 165.0,
    "grader_duration_seconds": 26.0,
    "total_duration_seconds": 191.0
  },
  "claims": [
    {
      "claim": "The form has 12 fillable fields",
      "type": "factual",
      "verified": true,
      "evidence": "Counted 12 fields in field_info.json"
    }
  ],
  "user_notes_summary": {
    "uncertainties": ["Used 2023 data, may be stale"],
    "needs_review": [],
    "workarounds": ["Fell back to text overlay for non-fillable fields"]
  },
  "eval_feedback": {
    "suggestions": [
      {
        "assertion": "The output includes the name 'John Smith'",
        "reason": "A hallucinated document that mentions the name would also pass"
      }
    ],
    "overall": "Assertions check presence but not correctness."
  }
}

Fields:

• expectations[]: Graded expectations with evidence
• summary: Aggregate pass/fail counts
• execution_metrics: Tool usage and output size (from executor's metrics.json)
• timing: Wall clock timing (from timing.json)
• claims: Extracted and verified claims from the output
• user_notes_summary: Issues flagged by the executor
• eval_feedback: (optional) Improvement suggestions for the evals, only present when the grader identifies issues worth raising

metrics.json

Output from the executor agent. Located at <run-dir>/outputs/metrics.json.

{
  "tool_calls": {
    "Read": 5,
    "Write": 2,
    "Bash": 8,
    "Edit": 1,
    "Glob": 2,
    "Grep": 0
  },
  "total_tool_calls": 18,
  "total_steps": 6,
  "files_created": ["filled_form.pdf", "field_values.json"],
  "errors_encountered": 0,
  "output_chars": 12450,
  "transcript_chars": 3200
}

Fields:

• tool_calls: Count per tool type
• total_tool_calls: Sum of all tool calls
• total_steps: Number of major execution steps
• files_created: List of output files created
• errors_encountered: Number of errors during execution
• output_chars: Total character count of output files
• transcript_chars: Character count of transcript

timing.json

Wall clock timing for a run. Located at <run-dir>/timing.json.

How to capture: When a subagent task completes, the task notification includes total_tokens and duration_ms. Save these immediately — they are not persisted anywhere else and cannot be recovered after the fact.

{
  "total_tokens": 84852,
  "duration_ms": 23332,
  "total_duration_seconds": 23.3,
  "executor_start": "2026-01-15T10:30:00Z",
  "executor_end": "2026-01-15T10:32:45Z",
  "executor_duration_seconds": 165.0,
  "grader_start": "2026-01-15T10:32:46Z",
  "grader_end": "2026-01-15T10:33:12Z",
  "grader_duration_seconds": 26.0
}

benchmark.json

Output from Benchmark mode. Located at benchmarks/<timestamp>/benchmark.json.

{
  "metadata": {
    "skill_name": "pdf",
    "skill_path": "/path/to/pdf",
    "executor_model": "claude-sonnet-4-20250514",
    "analyzer_model": "most-capable-model",
    "timestamp": "2026-01-15T10:30:00Z",
    "evals_run": [1, 2, 3],
    "runs_per_configuration": 3
  },

  "runs": [
    {
      "eval_id": 1,
      "eval_name": "Ocean",
      "configuration": "with_skill",
      "run_number": 1,
      "result": {
        "pass_rate": 0.85,
        "passed": 6,
        "failed": 1,
        "total": 7,
        "time_seconds": 42.5,
        "tokens": 3800,
        "tool_calls": 18,
        "errors": 0
      },
      "expectations": [
        {"text": "...", "passed": true, "evidence": "..."}
      ],
      "notes": [
        "Used 2023 data, may be stale",
        "Fell back to text overlay for non-fillable fields"
      ]
    }
  ],

  "run_summary": {
    "with_skill": {
      "pass_rate": {"mean": 0.85, "stddev": 0.05, "min": 0.80, "max": 0.90},
      "time_seconds": {"mean": 45.0, "stddev": 12.0, "min": 32.0, "max": 58.0},
      "tokens": {"mean": 3800, "stddev": 400, "min": 3200, "max": 4100}
    },
    "without_skill": {
      "pass_rate": {"mean": 0.35, "stddev": 0.08, "min": 0.28, "max": 0.45},
      "time_seconds": {"mean": 32.0, "stddev": 8.0, "min": 24.0, "max": 42.0},
      "tokens": {"mean": 2100, "stddev": 300, "min": 1800, "max": 2500}
    },
    "delta": {
      "pass_rate": "+0.50",
      "time_seconds": "+13.0",
      "tokens": "+1700"
    }
  },

  "notes": [
    "Assertion 'Output is a PDF file' passes 100% in both configurations - may not differentiate skill value",
    "Eval 3 shows high variance (50% ± 40%) - may be flaky or model-dependent",
    "Without-skill runs consistently fail on table extraction expectations",
    "Skill adds 13s average execution time but improves pass rate by 50%"
  ]
}

Fields:

• metadata: Information about the benchmark run
  • skill_name: Name of the skill
  • timestamp: When the benchmark was run
  • evals_run: List of eval names or IDs
  • runs_per_configuration: Number of runs per config (e.g. 3)
• runs[]: Individual run results
  • eval_id: Numeric eval identifier
  • eval_name: Human-readable eval name (used as section header in the viewer)
  • configuration: Must be "with_skill" or "without_skill" (the viewer uses this exact string for grouping and color coding)
  • run_number: Integer run number (1, 2, 3...)
  • result: Nested object with pass_rate, passed, total, time_seconds, tokens, errors
• run_summary: Statistical aggregates per configuration
  • with_skill / without_skill: Each contains pass_rate, time_seconds, tokens objects with mean and stddev fields
  • delta: Difference strings like "+0.50", "+13.0", "+1700"
• notes: Freeform observations from the analyzer

Important: The viewer reads these field names exactly. Using config instead of configuration, or putting pass_rate at the top level of a run instead of nested under result, will cause the viewer to show empty/zero values. Always reference this schema when generating benchmark.json manually.

comparison.json

Output from blind comparator. Located at <grading-dir>/comparison-N.json.

{
  "winner": "A",
  "reasoning": "Output A provides a complete solution with proper formatting and all required fields. Output B is missing the date field and has formatting inconsistencies.",
  "rubric": {
    "A": {
      "content": {
        "correctness": 5,
        "completeness": 5,
        "accuracy": 4
      },
      "structure": {
        "organization": 4,
        "formatting": 5,
        "usability": 4
      },
      "content_score": 4.7,
      "structure_score": 4.3,
      "overall_score": 9.0
    },
    "B": {
      "content": {
        "correctness": 3,
        "completeness": 2,
        "accuracy": 3
      },
      "structure": {
        "organization": 3,
        "formatting": 2,
        "usability": 3
      },
      "content_score": 2.7,
      "structure_score": 2.7,
      "overall_score": 5.4
    }
  },
  "output_quality": {
    "A": {
      "score": 9,
      "strengths": ["Complete solution", "Well-formatted", "All fields present"],
      "weaknesses": ["Minor style inconsistency in header"]
    },
    "B": {
      "score": 5,
      "strengths": ["Readable output", "Correct basic structure"],
      "weaknesses": ["Missing date field", "Formatting inconsistencies", "Partial data extraction"]
    }
  },
  "expectation_results": {
    "A": {
      "passed": 4,
      "total": 5,
      "pass_rate": 0.80,
      "details": [
        {"text": "Output includes name", "passed": true}
      ]
    },
    "B": {
      "passed": 3,
      "total": 5,
      "pass_rate": 0.60,
      "details": [
        {"text": "Output includes name", "passed": true}
      ]
    }
  }
}

analysis.json

Output from post-hoc analyzer. Located at <grading-dir>/analysis.json.

{
  "comparison_summary": {
    "winner": "A",
    "winner_skill": "path/to/winner/skill",
    "loser_skill": "path/to/loser/skill",
    "comparator_reasoning": "Brief summary of why comparator chose winner"
  },
  "winner_strengths": [
    "Clear step-by-step instructions for handling multi-page documents",
    "Included validation script that caught formatting errors"
  ],
  "loser_weaknesses": [
    "Vague instruction 'process the document appropriately' led to inconsistent behavior",
    "No script for validation, agent had to improvise"
  ],
  "instruction_following": {
    "winner": {
      "score": 9,
      "issues": ["Minor: skipped optional logging step"]
    },
    "loser": {
      "score": 6,
      "issues": [
        "Did not use the skill's formatting template",
        "Invented own approach instead of following step 3"
      ]
    }
  },
  "improvement_suggestions": [
    {
      "priority": "high",
      "category": "instructions",
      "suggestion": "Replace 'process the document appropriately' with explicit steps",
      "expected_impact": "Would eliminate ambiguity that caused inconsistent behavior"
    }
  ],
  "transcript_insights": {
    "winner_execution_pattern": "Read skill -> Followed 5-step process -> Used validation script",
    "loser_execution_pattern": "Read skill -> Unclear on approach -> Tried 3 different methods"
  }
}

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