Everything Claude Code (ECC) — Agent Harness Performance System Skill by [ara.so](https://ara.so) — Daily 2026 Skills collection. Everything Claude Code (ECC) is a production ready performance optimization system for AI agent harnesses. It provides specialized subagents, reusable skills, custom slash commands, memory persisting hooks, security scanning, and language specific rules — all evolved from 10+ months of daily real world use. Works across Claude Code, Cursor, Codex, OpenCode, and Antigravity. Installation Option 1: Plugin Marketplace (Recommended) Option 2: Manual Clone Install Rules (Always Required) Claude Code plugins cannot auto distribute rules — install them manually via ./install.sh or copy from rules/ into your project's .claude/rules/ directory. Directory Structure Key Commands After installation, use the namespaced form (plugin install) or short form (manual install): With manual install, drop the everything claude code: prefix: /plan , /sessions , etc. Hook Runtime Controls ECC hooks fire at agent lifecycle events. Control strictness at runtime without editing files: Hook events covered: SessionStart , Stop , PostEdit , PreBash , PostBash , and more. Package Manager Detection ECC auto detects your package manager with this priority chain: 1. CLAUDE PACKAGE MANAGER environment variable 2. .claude/package manager.json (project level) 3. package.json → packageManager field 4. Lock file detection ( package lock.json , yarn.lock , pnpm lock.yaml , bun.lockb ) 5. ~/.claude/package manager.json (global) 6. First available manager as fallback Skills System Skills are markdown modules the agent loads to gain domain expertise. Install individually or in bulk. Using a Skill Notable Built in Skills Skill Purpose search first Research before coding — avoids hallucinated APIs cost aware llm pipeline Optimizes token spend across model calls content hash cache pattern Cache invalidation via content hashing skill stocktake Audits which skills are loaded and active frontend slides Zero dependency HTML presentation builder configure ecc Guided interactive ECC setup wizard swift actor persistence Swift concurrency + persistence patterns regex vs llm structured text Decides when to use regex vs LLM parsing Writing a Custom Skill Create skills/my skill.md : Instincts System (Continuous Learning) Instincts are session extracted patterns saved for reuse. They carry confidence scores and evolve over time. Export an Instinct Instinct File Format Rules Architecture Rules enforce coding standards per language. Install only what your stack needs. Rule Directory Layout Agents (Subagent Delegation) Agents are specialized personas the orchestrator delegates to: Available agents include: planner , architect , researcher , verifier , security auditor , and more. Each lives in agents/<name .md with its own system prompt, tools list, and constraints. AgentShield Security Scanning Run security scans directly from Claude Code: This invokes the AgentShield scanner (1282 tests, 102 rules) against your codebase and surfaces: Hardcoded secrets Injection vulnerabilities Insecure dependencies Agent prompt injection patterns Memory Persistence Hooks ECC hooks automatically save and restore session context: Cross Platform Support Platform Support Claude Code Full (agents, commands, skills, hooks, rules) Cursor Full (via target cursor installer flag) OpenCode Full (plugin system, 20+ hook event types, 3 native tools) Codex CLI Full ( codex.md generated via /codex setup ) Codex App Full ( AGENTS.md based) Antigravity Full (via target antigravity installer flag) Common Patterns Research First Development Token Optimization Parallelization with Git Worktrees Verification Loop Troubleshooting Plugin commands not found after install Rules not applied Hooks not firing Instinct import drops content Ensure you're on v1.4.1+. Earlier versions had a bug where parse instinct file() silently dropped Action/Evidence/Examples sections. Pull latest and re run. Wrong package manager used Resources Homepage: https://ecc.tools GitHub: https://github.com/affaan m/everything claude code GitHub App (Marketplace): https://github.com/marketplace/ecc tools npm (universal): ecc universal npm (security): ecc agentshield Shorthand Guide: https://x.com/affaanmustafa/status/2012378465664745795 Longform Guide: https://x.com/affaanmustafa/status/2014040193557471352

everything-claude-code-harness