v3.13.0 latest March 2026

New Frontmatter Fields

• + effort field validation (low, medium, high)
• + maxTurns field validation with runaway detection (>100)
• + disallowedTools validation with allowed-tools overlap detection
• + Model aliases accepted: opus, sonnet, haiku
• + Spec version updated to 2026-03-20

v3.12.0 March 2026

Skill Discovery

• + skillcheck discover CLI command and skillcheck_discover MCP tool
• + Multi-platform scanning: Claude Code, Cursor, Windsurf, Codex CLI
• + Scans CLAUDE.md, .cursorrules, AGENTS.md, custom commands, hooks
• + Confidence scoring (HIGH/MEDIUM/LOW) per candidate
• + Platform auto-detection with per-candidate tagging
• + Redundancy detection across config files
• + Free: see candidates. Pro (--generate): auto-create SKILL.md files

v3.11.0 March 2026

Anti-Pattern Detection

• + 4.7-desc-workflow-steps (Free): flags descriptions that summarize workflow steps
• + 12.5-no-exit-criteria: phased skills missing exit criteria per phase
• + 12.6-unbounded-iteration: catches unbounded "for each" loops
• + 15.6-subagent-no-return-format: subagent prompt checks
• + 12.7-verbosity-detection: flags unnecessary explanations of well-known concepts
• + 12.8-feedback-loop-detection: flags quality-critical skills lacking verify steps
• + Skipped checks shown as "not applicable" instead of silently omitted
• + Accurate passed count: "Passed: N / M applicable"

v3.10.0 March 2026

Agent Readiness (L0-L3)

• + 6 new validation pillars with 28 checks (prefixes 13-18, Pro tier)
• + Reference Integrity: dangling references, excessive count, organization
• + Eval Readiness: success criteria, input/output examples, binary verdicts
• + Orchestration Safety: budget caps, phase boundaries, human checkpoints
• + Autonomy Design: stop conditions, safety guardrails, rollback, idempotency
• + Composability: input/output contracts, mode awareness, interface sections
• + Observability: progress reporting, confidence levels, phase boundaries
• + L0-L3 maturity scoring for agent-ready skills
• + WASM web validator at validate.getskillcheck.com
• + 82 total checks across 18 categories

v3.9.0 March 2026

Claude Code v2.1.69-71 Sync

• + New tools in KnownTools: CronCreate, CronDelete, CronList, EnterWorktree
• + Quality check 8.8-uses-skill-dir-var for ${CLAUDE_SKILL_DIR}
• + Example XML block tracking in ambiguous term and wisdom checks
• + Description severity softened from required to recommended
• + Version moved from top-level to metadata block

v3.8.0 March 2026

Wisdom Detection & Format Lint

• + 4.6-wisdom-platitude (Free): detects generic advice that wastes tokens
• + 2.8-anti-pattern-format (Free): flags prose anti-pattern docs, suggests tables
• + Progressive disclosure via references/ directory

v3.7.0 March 2026

Progressive Disclosure & Skill Sync

• + SKILL.md uses references/ for context-efficient loading
• + Version sync across CLI, MCP server, and web server

v3.6.0 February 2026

Anthropic Guide Alignment

• + Aligned with "The Complete Guide to Building Skills for Claude" (Anthropic, Feb 2026)
• + 4.4-body-misplaced-routing: flags "When to Use" sections in body
• + Routing trigger content moved to description field

v3.5.0 February 2026

Community Patterns

• + Checks informed by scanning 1434 community skills
• + scan command for batch validation of skill repositories
• + report command for HTML validation reports

v3.4.0 January 2026

Quality Patterns (Strengths)

• + SkillCheck now recognizes positive patterns, not just issues
• + Free: example section, error handling, trigger phrases, output format
• + Pro: negative triggers, boundary conditions, version pinning

v3.3.0 January 2026

Description & Claude Code Fields

• + 4.4-desc-use-when: suggests "Use when..." description format
• + 4.5-desc-no-triggers: warns when descriptions lack trigger phrases
• + Claude Code frontmatter validation: model, context, agent, hooks

v3.1.0 January 2026

Configuration & Plugins

• + YAML configuration via .skillcheck.yaml
• + Plugin system for custom checks
• + Audit logging for compliance
• + Custom rules with pattern matching

v3.0.0 December 2025

Knowledge Source Architecture

• + SKILL.md contains complete validation knowledge (no MCP dependency)
• + Architecture rewrite: skill file is the source of truth

v2.0.0 December 2025

agentskills Spec Alignment

• + Aligned with official agentskills specification
• + Breaking: version field no longer required, allowed-tools format changed

v1.0.0 December 2025

Initial Release

• + CLI tool for validating Claude Code skills
• + MCP server for Claude Code integration
• + Web server with API endpoint