diff --git a/AGENTS.md b/AGENTS.md
index 9f5af3b30..e53b620c6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -9,3 +9,4 @@ Open source framework for structured, agent-assisted software delivery.
   `quality` mirrors the checks in `.github/workflows/quality.yaml`.
 
 - Skill validation rules are in `tools/skill-validator.md`.
+- Deterministic skill checks run via `npm run validate:skills` (included in `quality`).
diff --git a/package.json b/package.json
index e76f9d0dc..1eb1df26e 100644
--- a/package.json
+++ b/package.json
@@ -39,12 +39,13 @@
     "lint:fix": "eslint . --ext .js,.cjs,.mjs,.yaml --fix",
     "lint:md": "markdownlint-cli2 \"**/*.md\"",
     "prepare": "command -v husky >/dev/null 2>&1 && husky || exit 0",
-    "quality": "npm run format:check && npm run lint && npm run lint:md && npm run docs:build && npm run test:install && npm run validate:refs",
+    "quality": "npm run format:check && npm run lint && npm run lint:md && npm run docs:build && npm run test:install && npm run validate:refs && npm run validate:skills",
     "rebundle": "node tools/cli/bundlers/bundle-web.js rebundle",
     "test": "npm run test:refs && npm run test:install && npm run lint && npm run lint:md && npm run format:check",
     "test:install": "node test/test-installation-components.js",
     "test:refs": "node test/test-file-refs-csv.js",
-    "validate:refs": "node tools/validate-file-refs.js --strict"
+    "validate:refs": "node tools/validate-file-refs.js --strict",
+    "validate:skills": "node tools/validate-skills.js --strict"
   },
   "lint-staged": {
     "*.{js,cjs,mjs}": [
diff --git a/tools/skill-validator.md b/tools/skill-validator.md
index 4ed4b3eda..543c8370a 100644
--- a/tools/skill-validator.md
+++ b/tools/skill-validator.md
@@ -2,14 +2,27 @@
 
 An LLM-readable validation prompt for skills following the Agent Skills open standard.
 
+## First Pass — Deterministic Checks
+
+Before running inference-based validation, run the deterministic validator:
+
+```bash
+node tools/validate-skills.js --json path/to/skill-dir
+```
+
+This checks 13 rules deterministically: SKILL-01, SKILL-02, SKILL-03, SKILL-04, SKILL-05, SKILL-06, WF-01, WF-02, PATH-02, STEP-01, STEP-06, STEP-07, SEQ-02.
+
+Review its JSON output. For any rule that produced **zero findings** in the first pass, **skip it** during inference-based validation below — it has already been verified. If a rule produced any findings, the inference validator should still review that rule (some rules like SKILL-04 and SKILL-06 have sub-checks that benefit from judgment). Focus your inference effort on the remaining rules that require judgment (PATH-01, PATH-03, PATH-04, PATH-05, WF-03, STEP-02, STEP-03, STEP-04, STEP-05, SEQ-01, REF-01, REF-02, REF-03).
+
 ## How to Use
 
 1. You are given a **skill directory path** to validate.
-2. Read every file in the skill directory recursively.
-3. Apply every rule in the catalog below to every applicable file.
-4. Produce a findings report using the report template at the end.
+2. Run the deterministic first pass (see above) and note which rules passed.
+3. Read every file in the skill directory recursively.
+4. Apply every rule in the catalog below to every applicable file, **skipping rules that passed the deterministic first pass**.
+5. Produce a findings report using the report template at the end, including any deterministic findings from the first pass.
 
-If no findings are generated, the skill passes validation.
+If no findings are generated (from either pass), the skill passes validation.
 
 ---
 
@@ -103,6 +116,7 @@ If no findings are generated, the skill passes validation.
   - A legitimate external path expression (must not violate PATH-05 — no paths into another skill's directory)
 
   It must NOT be a path to a file within the skill directory (see PATH-04), nor a path into another skill's directory (see PATH-05).
+
 - **Detection:** For each frontmatter variable, check if its value resolves to a file inside the skill (e.g., starts with `./`, `{installed_path}`, or is a bare relative path to a sibling file). If so, it is an intra-skill path variable. Also check if the value is a path into another skill's directory — if so, it violates PATH-05 and is not a legitimate external path.
 - **Fix:** Remove the variable. Use a hardcoded relative path inline where the file is referenced.
 
@@ -294,11 +308,11 @@ When reporting findings, use this format:
 ## Summary
 
 | Severity | Count |
-|----------|-------|
-| CRITICAL | N |
-| HIGH     | N |
-| MEDIUM   | N |
-| LOW      | N |
+| -------- | ----- |
+| CRITICAL | N     |
+| HIGH     | N     |
+| MEDIUM   | N     |
+| LOW      | N     |
 
 ## Findings
 
@@ -329,28 +343,34 @@ Quick-reference for the Agent Skills open standard.
 For the full standard, see: [Agent Skills specification](https://agentskills.io/specification)
 
 ### Structure
+
 - Every skill is a directory with `SKILL.md` as the required entrypoint
 - YAML frontmatter between `---` markers provides metadata; markdown body provides instructions
 - Supporting files (scripts, templates, references) live alongside SKILL.md
 
 ### Path resolution
+
 - Relative file references resolve from the directory of the file that contains the reference, not from the skill root
 - Example: from `branch-a/deep/next.md`, `./deeper/final.md` resolves to `branch-a/deep/deeper/final.md`
 - Example: from `branch-a/deep/next.md`, `./branch-b/alt/leaf.md` incorrectly resolves to `branch-a/deep/branch-b/alt/leaf.md`
 
 ### Frontmatter fields (standard)
+
 - `name`: lowercase letters, numbers, hyphens only; max 64 chars; no "anthropic" or "claude"
 - `description`: required, max 1024 chars; should state what the skill does AND when to use it
 
 ### Progressive disclosure — three loading levels
+
 - **L1 Metadata** (~100 tokens): `name` + `description` loaded at startup into system prompt
 - **L2 Instructions** (<5k tokens): SKILL.md body loaded only when skill is triggered
 - **L3 Resources** (unlimited): additional files + scripts loaded/executed on demand; script output enters context, script code does not
 
 ### Key design principle
+
 - Skills are filesystem-based directories, not API payloads — Claude reads them via bash/file tools
 - Keep SKILL.md focused; offload detailed reference to separate files
 
 ### Practical tips
+
 - Keep SKILL.md under 500 lines
 - `description` drives auto-discovery — use keywords users would naturally say
diff --git a/tools/validate-skills.js b/tools/validate-skills.js
new file mode 100644
index 000000000..ea13b80e3
--- /dev/null
+++ b/tools/validate-skills.js
@@ -0,0 +1,705 @@
+/**
+ * Deterministic Skill Validator
+ *
+ * Validates 13 deterministic rules across all skill directories.
+ * Acts as a fast first-pass complement to the inference-based skill validator.
+ *
+ * What it checks:
+ * - SKILL-01: SKILL.md exists
+ * - SKILL-02: SKILL.md frontmatter has name
+ * - SKILL-03: SKILL.md frontmatter has description
+ * - SKILL-04: name format (lowercase, hyphens, no forbidden substrings)
+ * - SKILL-05: name matches directory basename
+ * - SKILL-06: description quality (length, "Use when"/"Use if")
+ * - WF-01: workflow.md frontmatter has no name
+ * - WF-02: workflow.md frontmatter has no description
+ * - PATH-02: no installed_path variable
+ * - STEP-01: step filename format
+ * - STEP-06: step frontmatter has no name/description
+ * - STEP-07: step count 2-10
+ * - SEQ-02: no time estimates
+ *
+ * Usage:
+ *   node tools/validate-skills.js                    # All skills, human-readable
+ *   node tools/validate-skills.js path/to/skill-dir  # Single skill
+ *   node tools/validate-skills.js --strict           # Exit 1 on HIGH+ findings
+ *   node tools/validate-skills.js --json             # JSON output
+ */
+
+const fs = require('node:fs');
+const path = require('node:path');
+
+const PROJECT_ROOT = path.resolve(__dirname, '..');
+const SRC_DIR = path.join(PROJECT_ROOT, 'src');
+
+// --- CLI Parsing ---
+
+const args = process.argv.slice(2);
+const STRICT = args.includes('--strict');
+const JSON_OUTPUT = args.includes('--json');
+const positionalArgs = args.filter((a) => !a.startsWith('--'));
+
+// --- Constants ---
+
+const SKILL_LOCATIONS = [path.join(SRC_DIR, 'core', 'skills'), path.join(SRC_DIR, 'core', 'tasks'), path.join(SRC_DIR, 'bmm', 'workflows')];
+
+// Agent skills live separately
+const AGENT_LOCATION = path.join(SRC_DIR, 'bmm', 'agents');
+
+const NAME_REGEX = /^[a-z0-9][a-z0-9-]{0,62}[a-z0-9]$/;
+const STEP_FILENAME_REGEX = /^step-\d{2}[a-z]?-[a-z0-9-]+\.md$/;
+const FORBIDDEN_NAME_SUBSTRINGS = ['anthropic', 'claude'];
+const TIME_ESTIMATE_PATTERNS = [/takes?\s+\d+\s*min/i, /~\s*\d+\s*min/i, /estimated\s+time/i, /\bETA\b/];
+
+const SEVERITY_ORDER = { CRITICAL: 0, HIGH: 1, MEDIUM: 2, LOW: 3 };
+
+// --- Output Escaping ---
+
+function escapeAnnotation(str) {
+  return str.replaceAll('%', '%25').replaceAll('\r', '%0D').replaceAll('\n', '%0A');
+}
+
+function escapeTableCell(str) {
+  return String(str).replaceAll('|', String.raw`\|`);
+}
+
+// --- Frontmatter Parsing ---
+
+/**
+ * Parse YAML frontmatter from a markdown file.
+ * Returns an object with key-value pairs, or null if no frontmatter.
+ */
+function parseFrontmatter(content) {
+  const trimmed = content.trimStart();
+  if (!trimmed.startsWith('---')) return null;
+
+  const endIndex = trimmed.indexOf('\n---', 3);
+  if (endIndex === -1) return null;
+
+  const fmBlock = trimmed.slice(3, endIndex).trim();
+  if (fmBlock === '') return {};
+
+  const result = {};
+  for (const line of fmBlock.split('\n')) {
+    const colonIndex = line.indexOf(':');
+    if (colonIndex === -1) continue;
+    // Skip indented lines (nested YAML values)
+    if (line[0] === ' ' || line[0] === '\t') continue;
+    const key = line.slice(0, colonIndex).trim();
+    let value = line.slice(colonIndex + 1).trim();
+    // Strip surrounding quotes (single or double)
+    if ((value.startsWith("'") && value.endsWith("'")) || (value.startsWith('"') && value.endsWith('"'))) {
+      value = value.slice(1, -1);
+    }
+    result[key] = value;
+  }
+
+  return result;
+}
+
+/**
+ * Parse YAML frontmatter, handling multiline values (description often spans lines).
+ * Returns an object with key-value pairs, or null if no frontmatter.
+ */
+function parseFrontmatterMultiline(content) {
+  const trimmed = content.trimStart();
+  if (!trimmed.startsWith('---')) return null;
+
+  const endIndex = trimmed.indexOf('\n---', 3);
+  if (endIndex === -1) return null;
+
+  const fmBlock = trimmed.slice(3, endIndex).trim();
+  if (fmBlock === '') return {};
+
+  const result = {};
+  let currentKey = null;
+  let currentValue = '';
+
+  for (const line of fmBlock.split('\n')) {
+    const colonIndex = line.indexOf(':');
+    // New key-value pair: must start at column 0 (no leading whitespace) and have a colon
+    if (colonIndex > 0 && line[0] !== ' ' && line[0] !== '\t') {
+      // Save previous key
+      if (currentKey !== null) {
+        result[currentKey] = stripQuotes(currentValue.trim());
+      }
+      currentKey = line.slice(0, colonIndex).trim();
+      currentValue = line.slice(colonIndex + 1);
+    } else if (currentKey !== null) {
+      // Continuation of multiline value
+      currentValue += '\n' + line;
+    }
+  }
+
+  // Save last key
+  if (currentKey !== null) {
+    result[currentKey] = stripQuotes(currentValue.trim());
+  }
+
+  return result;
+}
+
+function stripQuotes(value) {
+  if ((value.startsWith("'") && value.endsWith("'")) || (value.startsWith('"') && value.endsWith('"'))) {
+    return value.slice(1, -1);
+  }
+  return value;
+}
+
+// --- Safe File Reading ---
+
+/**
+ * Read a file safely, returning null on error.
+ * Pushes a warning finding if the file cannot be read.
+ */
+function safeReadFile(filePath, findings, relFile) {
+  try {
+    return fs.readFileSync(filePath, 'utf-8');
+  } catch (error) {
+    findings.push({
+      rule: 'READ-ERR',
+      title: 'File Read Error',
+      severity: 'MEDIUM',
+      file: relFile || path.basename(filePath),
+      detail: `Cannot read file: ${error.message}`,
+      fix: 'Check file permissions and ensure the file exists.',
+    });
+    return null;
+  }
+}
+
+// --- Code Block Stripping ---
+
+function stripCodeBlocks(content) {
+  return content.replaceAll(/```[\s\S]*?```/g, (m) => m.replaceAll(/[^\n]/g, ''));
+}
+
+// --- Skill Discovery ---
+
+function discoverSkillDirs(rootDirs) {
+  const skillDirs = [];
+
+  function walk(dir) {
+    if (!fs.existsSync(dir)) return;
+    const entries = fs.readdirSync(dir, { withFileTypes: true });
+
+    for (const entry of entries) {
+      if (!entry.isDirectory()) continue;
+      if (entry.name === 'node_modules' || entry.name === '.git') continue;
+
+      const fullPath = path.join(dir, entry.name);
+      const skillMd = path.join(fullPath, 'SKILL.md');
+
+      if (fs.existsSync(skillMd)) {
+        skillDirs.push(fullPath);
+      }
+
+      // Keep walking into subdirectories to find nested skills
+      walk(fullPath);
+    }
+  }
+
+  for (const rootDir of rootDirs) {
+    walk(rootDir);
+  }
+
+  return skillDirs.sort();
+}
+
+// --- File Collection ---
+
+function collectSkillFiles(skillDir) {
+  const files = [];
+
+  function walk(dir) {
+    const entries = fs.readdirSync(dir, { withFileTypes: true });
+    for (const entry of entries) {
+      if (entry.name === 'node_modules' || entry.name === '.git') continue;
+      const fullPath = path.join(dir, entry.name);
+      if (entry.isDirectory()) {
+        walk(fullPath);
+      } else if (entry.isFile()) {
+        files.push(fullPath);
+      }
+    }
+  }
+
+  walk(skillDir);
+  return files;
+}
+
+// --- Rule Checks ---
+
+function validateSkill(skillDir) {
+  const findings = [];
+  const dirName = path.basename(skillDir);
+  const skillMdPath = path.join(skillDir, 'SKILL.md');
+  const workflowMdPath = path.join(skillDir, 'workflow.md');
+  const stepsDir = path.join(skillDir, 'steps');
+
+  // Collect all files in the skill for PATH-02 and SEQ-02
+  const allFiles = collectSkillFiles(skillDir);
+
+  // --- SKILL-01: SKILL.md must exist ---
+  if (!fs.existsSync(skillMdPath)) {
+    findings.push({
+      rule: 'SKILL-01',
+      title: 'SKILL.md Must Exist',
+      severity: 'CRITICAL',
+      file: 'SKILL.md',
+      detail: 'SKILL.md not found in skill directory.',
+      fix: 'Create SKILL.md as the skill entrypoint.',
+    });
+    // Cannot check SKILL-02 through SKILL-06 without SKILL.md
+    return findings;
+  }
+
+  const skillContent = safeReadFile(skillMdPath, findings, 'SKILL.md');
+  if (skillContent === null) return findings;
+  const skillFm = parseFrontmatterMultiline(skillContent);
+
+  // --- SKILL-02: frontmatter has name ---
+  if (!skillFm || !('name' in skillFm)) {
+    findings.push({
+      rule: 'SKILL-02',
+      title: 'SKILL.md Must Have name in Frontmatter',
+      severity: 'CRITICAL',
+      file: 'SKILL.md',
+      detail: 'Frontmatter is missing the `name` field.',
+      fix: 'Add `name: <skill-name>` to the frontmatter.',
+    });
+  } else if (skillFm.name === '') {
+    findings.push({
+      rule: 'SKILL-02',
+      title: 'SKILL.md Must Have name in Frontmatter',
+      severity: 'CRITICAL',
+      file: 'SKILL.md',
+      detail: 'Frontmatter `name` field is empty.',
+      fix: 'Set `name` to the skill directory name (kebab-case).',
+    });
+  }
+
+  // --- SKILL-03: frontmatter has description ---
+  if (!skillFm || !('description' in skillFm)) {
+    findings.push({
+      rule: 'SKILL-03',
+      title: 'SKILL.md Must Have description in Frontmatter',
+      severity: 'CRITICAL',
+      file: 'SKILL.md',
+      detail: 'Frontmatter is missing the `description` field.',
+      fix: 'Add `description: <what it does and when to use it>` to the frontmatter.',
+    });
+  } else if (skillFm.description === '') {
+    findings.push({
+      rule: 'SKILL-03',
+      title: 'SKILL.md Must Have description in Frontmatter',
+      severity: 'CRITICAL',
+      file: 'SKILL.md',
+      detail: 'Frontmatter `description` field is empty.',
+      fix: 'Add a description stating what the skill does and when to use it.',
+    });
+  }
+
+  const name = skillFm && skillFm.name;
+  const description = skillFm && skillFm.description;
+
+  // --- SKILL-04: name format ---
+  if (name) {
+    if (!NAME_REGEX.test(name)) {
+      findings.push({
+        rule: 'SKILL-04',
+        title: 'name Format',
+        severity: 'HIGH',
+        file: 'SKILL.md',
+        detail: `name "${name}" does not match pattern: ${NAME_REGEX}`,
+        fix: 'Rename to comply with lowercase letters, numbers, and hyphens only (max 64 chars).',
+      });
+    }
+
+    for (const forbidden of FORBIDDEN_NAME_SUBSTRINGS) {
+      if (name.toLowerCase().includes(forbidden)) {
+        findings.push({
+          rule: 'SKILL-04',
+          title: 'name Format',
+          severity: 'HIGH',
+          file: 'SKILL.md',
+          detail: `name "${name}" contains forbidden substring "${forbidden}".`,
+          fix: `Remove "${forbidden}" from the name.`,
+        });
+      }
+    }
+  }
+
+  // --- SKILL-05: name matches directory ---
+  if (name && name !== dirName) {
+    findings.push({
+      rule: 'SKILL-05',
+      title: 'name Must Match Directory Name',
+      severity: 'HIGH',
+      file: 'SKILL.md',
+      detail: `name "${name}" does not match directory name "${dirName}".`,
+      fix: `Change name to "${dirName}" or rename the directory.`,
+    });
+  }
+
+  // --- SKILL-06: description quality ---
+  if (description) {
+    if (description.length > 1024) {
+      findings.push({
+        rule: 'SKILL-06',
+        title: 'description Quality',
+        severity: 'MEDIUM',
+        file: 'SKILL.md',
+        detail: `description is ${description.length} characters (max 1024).`,
+        fix: 'Shorten the description to 1024 characters or less.',
+      });
+    }
+
+    if (!/use\s+when\b/i.test(description) && !/use\s+if\b/i.test(description)) {
+      findings.push({
+        rule: 'SKILL-06',
+        title: 'description Quality',
+        severity: 'MEDIUM',
+        file: 'SKILL.md',
+        detail: 'description does not contain "Use when" or "Use if" trigger phrase.',
+        fix: 'Append a "Use when..." clause to explain when to invoke this skill.',
+      });
+    }
+  }
+
+  // --- WF-01 / WF-02: workflow.md must NOT have name/description ---
+  if (fs.existsSync(workflowMdPath)) {
+    const wfContent = safeReadFile(workflowMdPath, findings, 'workflow.md');
+    const wfFm = wfContent ? parseFrontmatter(wfContent) : null;
+
+    if (wfFm && 'name' in wfFm) {
+      findings.push({
+        rule: 'WF-01',
+        title: 'workflow.md Must NOT Have name in Frontmatter',
+        severity: 'HIGH',
+        file: 'workflow.md',
+        detail: 'workflow.md frontmatter contains `name` — this belongs only in SKILL.md.',
+        fix: 'Remove the `name:` line from workflow.md frontmatter.',
+      });
+    }
+
+    if (wfFm && 'description' in wfFm) {
+      findings.push({
+        rule: 'WF-02',
+        title: 'workflow.md Must NOT Have description in Frontmatter',
+        severity: 'HIGH',
+        file: 'workflow.md',
+        detail: 'workflow.md frontmatter contains `description` — this belongs only in SKILL.md.',
+        fix: 'Remove the `description:` line from workflow.md frontmatter.',
+      });
+    }
+  }
+
+  // --- PATH-02: no installed_path ---
+  for (const filePath of allFiles) {
+    // Only check markdown and yaml files
+    const ext = path.extname(filePath);
+    if (!['.md', '.yaml', '.yml'].includes(ext)) continue;
+
+    const relFile = path.relative(skillDir, filePath);
+    const content = safeReadFile(filePath, findings, relFile);
+    if (content === null) continue;
+
+    // Check frontmatter for installed_path key
+    const fm = parseFrontmatter(content);
+    if (fm && 'installed_path' in fm) {
+      findings.push({
+        rule: 'PATH-02',
+        title: 'No installed_path Variable',
+        severity: 'HIGH',
+        file: relFile,
+        detail: 'Frontmatter contains `installed_path:` key.',
+        fix: 'Remove `installed_path` from frontmatter. Use relative paths instead.',
+      });
+    }
+
+    // Check content for {installed_path}
+    const stripped = stripCodeBlocks(content);
+    const lines = stripped.split('\n');
+    for (const [i, line] of lines.entries()) {
+      if (line.includes('{installed_path}')) {
+        findings.push({
+          rule: 'PATH-02',
+          title: 'No installed_path Variable',
+          severity: 'HIGH',
+          file: relFile,
+          line: i + 1,
+          detail: '`{installed_path}` reference found in content.',
+          fix: 'Replace `{installed_path}/path` with a relative path (`./path` or `../path`).',
+        });
+      }
+    }
+  }
+
+  // --- STEP-01: step filename format ---
+  // --- STEP-06: step frontmatter no name/description ---
+  // --- STEP-07: step count ---
+  // Only check the literal steps/ directory (variant directories like steps-c, steps-v
+  // use different naming conventions and are excluded per the rule specification)
+  if (fs.existsSync(stepsDir) && fs.statSync(stepsDir).isDirectory()) {
+    const stepDirName = 'steps';
+    const stepFiles = fs.readdirSync(stepsDir).filter((f) => f.endsWith('.md'));
+
+    // STEP-01: filename format
+    for (const stepFile of stepFiles) {
+      if (!STEP_FILENAME_REGEX.test(stepFile)) {
+        findings.push({
+          rule: 'STEP-01',
+          title: 'Step File Naming',
+          severity: 'MEDIUM',
+          file: path.join(stepDirName, stepFile),
+          detail: `Filename "${stepFile}" does not match pattern: ${STEP_FILENAME_REGEX}`,
+          fix: 'Rename to step-NN-description.md (NN = zero-padded number, optional letter suffix).',
+        });
+      }
+    }
+
+    // STEP-06: step frontmatter has no name/description
+    for (const stepFile of stepFiles) {
+      const stepPath = path.join(stepsDir, stepFile);
+      const stepContent = safeReadFile(stepPath, findings, path.join(stepDirName, stepFile));
+      if (stepContent === null) continue;
+      const stepFm = parseFrontmatter(stepContent);
+
+      if (stepFm) {
+        if ('name' in stepFm) {
+          findings.push({
+            rule: 'STEP-06',
+            title: 'Step File Frontmatter: No name or description',
+            severity: 'MEDIUM',
+            file: path.join(stepDirName, stepFile),
+            detail: 'Step file frontmatter contains `name:` — this is metadata noise.',
+            fix: 'Remove `name:` from step file frontmatter.',
+          });
+        }
+        if ('description' in stepFm) {
+          findings.push({
+            rule: 'STEP-06',
+            title: 'Step File Frontmatter: No name or description',
+            severity: 'MEDIUM',
+            file: path.join(stepDirName, stepFile),
+            detail: 'Step file frontmatter contains `description:` — this is metadata noise.',
+            fix: 'Remove `description:` from step file frontmatter.',
+          });
+        }
+      }
+    }
+
+    // STEP-07: step count 2-10
+    const stepCount = stepFiles.filter((f) => f.startsWith('step-')).length;
+    if (stepCount > 0 && (stepCount < 2 || stepCount > 10)) {
+      const detail =
+        stepCount < 2
+          ? `Only ${stepCount} step file found — consider inlining into workflow.md.`
+          : `${stepCount} step files found — more than 10 risks LLM context degradation.`;
+      findings.push({
+        rule: 'STEP-07',
+        title: 'Step Count',
+        severity: 'LOW',
+        file: stepDirName + '/',
+        detail,
+        fix: stepCount > 10 ? 'Consider consolidating steps.' : 'Consider expanding or inlining.',
+      });
+    }
+  }
+
+  // --- SEQ-02: no time estimates ---
+  for (const filePath of allFiles) {
+    const ext = path.extname(filePath);
+    if (!['.md', '.yaml', '.yml'].includes(ext)) continue;
+
+    const relFile = path.relative(skillDir, filePath);
+    const content = safeReadFile(filePath, findings, relFile);
+    if (content === null) continue;
+    const stripped = stripCodeBlocks(content);
+    const lines = stripped.split('\n');
+
+    for (const [i, line] of lines.entries()) {
+      for (const pattern of TIME_ESTIMATE_PATTERNS) {
+        if (pattern.test(line)) {
+          findings.push({
+            rule: 'SEQ-02',
+            title: 'No Time Estimates',
+            severity: 'LOW',
+            file: relFile,
+            line: i + 1,
+            detail: `Time estimate pattern found: "${line.trim()}"`,
+            fix: 'Remove time estimates — AI execution speed varies too much.',
+          });
+          break; // Only report once per line
+        }
+      }
+    }
+  }
+
+  return findings;
+}
+
+// --- Output Formatting ---
+
+function formatHumanReadable(results) {
+  const output = [];
+  let totalFindings = 0;
+  const severityCounts = { CRITICAL: 0, HIGH: 0, MEDIUM: 0, LOW: 0 };
+
+  output.push(
+    `\nValidating skills in: ${SRC_DIR}`,
+    `Mode: ${STRICT ? 'STRICT (exit 1 on HIGH+)' : 'WARNING (exit 0)'}${JSON_OUTPUT ? ' + JSON' : ''}\n`,
+  );
+
+  let totalSkills = 0;
+  let skillsWithFindings = 0;
+
+  for (const { skillDir, findings } of results) {
+    totalSkills++;
+    const relDir = path.relative(PROJECT_ROOT, skillDir);
+
+    if (findings.length > 0) {
+      skillsWithFindings++;
+      output.push(`\n${relDir}`);
+
+      for (const f of findings) {
+        totalFindings++;
+        severityCounts[f.severity]++;
+        const location = f.line ? ` (line ${f.line})` : '';
+        output.push(`  [${f.severity}] ${f.rule} — ${f.title}`, `    File: ${f.file}${location}`, `    ${f.detail}`);
+
+        if (process.env.GITHUB_ACTIONS) {
+          const absFile = path.join(skillDir, f.file);
+          const ghFile = path.relative(PROJECT_ROOT, absFile);
+          const line = f.line || 1;
+          const level = f.severity === 'LOW' ? 'notice' : 'warning';
+          console.log(`::${level} file=${ghFile},line=${line}::${escapeAnnotation(`${f.rule}: ${f.detail}`)}`);
+        }
+      }
+    }
+  }
+
+  // Summary
+  output.push(
+    `\n${'─'.repeat(60)}`,
+    `\nSummary:`,
+    `   Skills scanned: ${totalSkills}`,
+    `   Skills with findings: ${skillsWithFindings}`,
+    `   Total findings: ${totalFindings}`,
+  );
+
+  if (totalFindings > 0) {
+    output.push('', `   | Severity | Count |`, `   |----------|-------|`);
+    for (const sev of ['CRITICAL', 'HIGH', 'MEDIUM', 'LOW']) {
+      if (severityCounts[sev] > 0) {
+        output.push(`   | ${sev.padEnd(8)} | ${String(severityCounts[sev]).padStart(5)} |`);
+      }
+    }
+  }
+
+  const hasHighPlus = severityCounts.CRITICAL > 0 || severityCounts.HIGH > 0;
+
+  if (totalFindings === 0) {
+    output.push(`\n   All skills passed validation!`);
+  } else if (STRICT && hasHighPlus) {
+    output.push(`\n   [STRICT MODE] HIGH+ findings found — exiting with failure.`);
+  } else if (STRICT) {
+    output.push(`\n   [STRICT MODE] Only MEDIUM/LOW findings — pass.`);
+  } else {
+    output.push(`\n   Run with --strict to treat HIGH+ findings as errors.`);
+  }
+
+  output.push('');
+
+  // Write GitHub Actions step summary
+  if (process.env.GITHUB_STEP_SUMMARY) {
+    let summary = '## Skill Validation\n\n';
+    if (totalFindings > 0) {
+      summary += '| Skill | Rule | Severity | File | Detail |\n';
+      summary += '|-------|------|----------|------|--------|\n';
+      for (const { skillDir, findings } of results) {
+        const relDir = path.relative(PROJECT_ROOT, skillDir);
+        for (const f of findings) {
+          summary += `| ${escapeTableCell(relDir)} | ${f.rule} | ${f.severity} | ${escapeTableCell(f.file)} | ${escapeTableCell(f.detail)} |\n`;
+        }
+      }
+      summary += '\n';
+    }
+    summary += `**${totalSkills} skills scanned, ${totalFindings} findings**\n`;
+    fs.appendFileSync(process.env.GITHUB_STEP_SUMMARY, summary);
+  }
+
+  return { output: output.join('\n'), hasHighPlus };
+}
+
+function formatJson(results) {
+  const allFindings = [];
+  for (const { skillDir, findings } of results) {
+    const relDir = path.relative(PROJECT_ROOT, skillDir);
+    for (const f of findings) {
+      allFindings.push({
+        skill: relDir,
+        rule: f.rule,
+        title: f.title,
+        severity: f.severity,
+        file: f.file,
+        line: f.line || null,
+        detail: f.detail,
+        fix: f.fix,
+      });
+    }
+  }
+
+  // Sort by severity
+  allFindings.sort((a, b) => SEVERITY_ORDER[a.severity] - SEVERITY_ORDER[b.severity]);
+
+  const hasHighPlus = allFindings.some((f) => f.severity === 'CRITICAL' || f.severity === 'HIGH');
+
+  return { output: JSON.stringify(allFindings, null, 2), hasHighPlus };
+}
+
+// --- Main ---
+
+if (require.main === module) {
+  // Determine which skills to validate
+  let skillDirs;
+
+  if (positionalArgs.length > 0) {
+    // Single skill directory specified
+    const target = path.resolve(positionalArgs[0]);
+    if (!fs.existsSync(target) || !fs.statSync(target).isDirectory()) {
+      console.error(`Error: "${positionalArgs[0]}" is not a valid directory.`);
+      process.exit(2);
+    }
+    skillDirs = [target];
+  } else {
+    // Discover all skills
+    const allLocations = [...SKILL_LOCATIONS, AGENT_LOCATION];
+    skillDirs = discoverSkillDirs(allLocations);
+  }
+
+  if (skillDirs.length === 0) {
+    console.error('No skill directories found.');
+    process.exit(2);
+  }
+
+  // Validate each skill
+  const results = [];
+  for (const skillDir of skillDirs) {
+    const findings = validateSkill(skillDir);
+    results.push({ skillDir, findings });
+  }
+
+  // Format output
+  const { output, hasHighPlus } = JSON_OUTPUT ? formatJson(results) : formatHumanReadable(results);
+  console.log(output);
+
+  // Exit code
+  if (STRICT && hasHighPlus) {
+    process.exit(1);
+  }
+}
+
+// --- Exports (for testing) ---
+module.exports = { parseFrontmatter, parseFrontmatterMultiline, validateSkill, discoverSkillDirs };