---
title: "Skill Spec Validation"
task: ""
lineage_type: import
upstream_source: https://github.com/K-Dense-AI/scientific-agent-skills/blob/991bd993/.github/workflows/skill-spec-validation.yml
upstream_sha: 991bd993
imported_at: 2026-08-08
prompt_class: prompt
upstream_changes: accepted
author: upstream
validated: false
---

name: Skill Spec Validation

on:
  pull_request:
    paths:
      - "skills/**"
      - "pyproject.toml"
      - "uv.lock"
      - ".github/workflows/skill-spec-validation.yml"
  push:
    branches:
      - main
    paths:
      - "skills/**"
  workflow_dispatch:

permissions:
  contents: read

concurrency:
  group: skill-spec-validation-${{ github.ref }}
  cancel-in-progress: true

jobs:
  validate:
    name: Validate skills against the Agent Skills spec
    runs-on: ubuntu-latest
    timeout-minutes: 15

    steps:
      - name: Checkout
        uses: actions/checkout@v6

      - name: Set up uv
        uses: astral-sh/setup-uv@v8.0.0
        with:
          enable-cache: true
          cache-dependency-glob: uv.lock
          python-version: "3.13"

      - name: Install dependencies
        run: uv sync --python 3.13

      # The reference validator from https://agentskills.io/specification. It checks the
      # closed set of allowed frontmatter fields, name rules (incl. directory match),
      # description/compatibility length limits, and parses frontmatter with strictyaml
      # -- which rejects JSON-style flow mappings such as `metadata: {"version": "1.0"}`.
      - name: skills-ref validate
        run: |
          set -uo pipefail
          fail=0
          for d in skills/*/; do
            if ! out=$(uv run skills-ref validate "$d" 2>&1); then
              fail=1
              echo "::error file=${d}SKILL.md::$(echo "$out" | tail -n +2 | tr '\n' ' ')"
              echo "FAIL $d"
              echo "$out" | sed 's/^/    /'
            fi
          done
          echo "Validated $(ls -d skills/*/ | wc -l) skills."
          exit $fail

      # Rules the reference validator does not enforce: this repo's metadata.version
      # requirement (see AGENTS.md), plus spec constraints skills-ref accepts but the
      # spec text requires -- allowed-tools must be a space-separated string, and
      # metadata values must be strings apart from the host-manifest blocks that have
      # to stay nested objects (see NESTED_OK below).
      - name: Repo and spec rules skills-ref does not check
        run: |
          uv run --with pyyaml python - <<'PY'
          import re
          import sys
          from pathlib import Path
          import yaml

          # Host manifest blocks that must stay nested mappings. OpenClaw's
          # resolveOpenClawManifestBlock() requires `typeof candidate === "object"`, so
          # encoding these as JSON strings silently disables its gating and credential
          # injection. Nested mappings still pass `skills-ref validate`.
          NESTED_OK = {"openclaw", "hermes"}

          # Requires the closing delimiter on its own line. A naive split("---") would
          # happily re-split at a `---` accidentally glued to the last frontmatter value.
          FM_RE = re.compile(r"\A---\n(.*?)\n---\n", re.S)

          errors, warnings = [], []
          for d in sorted(Path("skills").iterdir()):
              if not d.is_dir():
                  continue
              md = d / "SKILL.md"
              if not md.exists():
                  errors.append(f"{d}: missing SKILL.md")
                  continue
              text = md.read_text()
              m_fm = FM_RE.match(text)
              if not m_fm:
                  errors.append(
                      f"{md}: frontmatter must open with `---` and close with `---` "
                      f"on its own line"
                  )
                  continue
              fm = yaml.safe_load(m_fm.group(1))

              at = fm.get("allowed-tools")
              if at is not None:
                  if not isinstance(at, str):
                      errors.append(
                          f"{md}: allowed-tools must be a space-separated string, "
                          f"got {type(at).__name__}"
                      )
                  elif "," in at:
                      errors.append(
                          f"{md}: allowed-tools must be space-separated, not "
                          f"comma-separated: {at!r}"
                      )

              m = fm.get("metadata")
              if not isinstance(m, dict):
                  errors.append(f"{md}: missing a `metadata` mapping (see AGENTS.md)")
              else:
                  if "version" not in m:
                      errors.append(f"{md}: metadata.version is required (see AGENTS.md)")
                  for k, v in m.items():
                      if k in NESTED_OK:
                          if not isinstance(v, dict):
                              errors.append(
                                  f"{md}: metadata.{k} must stay a nested mapping, got "
                                  f"{type(v).__name__} -- a JSON string silently disables "
                                  f"host gating and credential injection"
                              )
                          continue
                      if isinstance(v, str):
                          continue
                      errors.append(
                          f"{md}: metadata.{k} must be a string, got {type(v).__name__} "
                          f"-- quote it (versions and dates especially)"
                      )

              lines = text.count("\n") + 1
              if lines > 500:
                  warnings.append(f"{md}: {lines} lines; the spec recommends under 500")

          for w in warnings:
              print(f"::warning file={w.split(':')[0]}::{w}")
          for e in errors:
              print(f"::error file={e.split(':')[0]}::{e}")
              print(f"FAIL {e}")
          print(f"\n{len(errors)} error(s), {len(warnings)} warning(s).")
          sys.exit(1 if errors else 0)
          PY