ECC is a toolkit that organizes and improves how coding agents work through skills, memory, security checks, research practices, and related extensions. It is for developers using agents such as Claude Code, Codex, OpenCode, and Cursor.
Borrowing it
Nothing to install: this file belongs to affaan-m/ECC. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/affaan-m/ECC/main/.kiro/steering/lessons-learned.mdgit clone --depth 1 https://github.com/affaan-m/ECCWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/affaan-m/ecc/lessons-learned)<a href="https://agentmods.dev/instructions/affaan-m/ecc/lessons-learned"><img src="https://agentmods.dev/badge/instructions/affaan-m/ecc/lessons-learned.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00671 | $0.00671 |
| Opus 5 | $0.00336 | $0.00336 |
| Sonnet 5 | $0.00134 | $0.00134 |
| Haiku 4.5 | $0.00067 | $0.00067 |
Grade A, and why
lessons-learned scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Lessons Learned
This file captures project-specific patterns, coding preferences, common pitfalls, and architectural decisions that emerge during development. It serves as a workaround for continuous learning by allowing you to document patterns manually.
How to use this file:
- The
extract-patternshook will suggest patterns after agent sessions - Review suggestions and add genuinely useful patterns below
- Edit this file directly to capture team conventions
- Keep it focused on project-specific insights, not general best practices
Project-Specific Patterns
Document patterns unique to this project that the team should follow.
Example: API Error Handling
// Always use our custom ApiError class for consistent error responses
throw new ApiError(404, 'Resource not found', { resourceId });
Code Style Preferences
Document team preferences that go beyond standard linting rules.
Example: Import Organization
// Group imports: external, internal, types
import { useState } from 'react';
import { Button } from '@/components/ui';
import type { User } from '@/types';
Kiro Hooks
install.sh is additive-only — it won't update existing installations
The installer skips any file that already exists in the target (if [ ! -f ... ]). Running it against a folder that already has .kiro/ will not overwrite or update hooks, agents, or steering files. To push updates to an existing project, manually copy the changed files or remove the target files first before re-running the installer.
README.md mirrors hook configurations — keep them in sync
The hooks table and Example 5 in README.md document the action type (runCommand vs askAgent) and behavior of each hook. When changing a hook's then.type or behavior, update both the hook file and the corresponding README entries to avoid misleading documentation.
Prefer askAgent over runCommand for file-event hooks
runCommand hooks on fileEdited or fileCreated events spawn a new terminal session every time they fire, creating friction. Use askAgent instead so the agent handles the task inline. Reserve runCommand for userTriggered hooks where a manual, isolated terminal run is intentional (e.g., quality-gate).
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- today First seen · 86 lines · 671 tokens per session scan A adae87c6158f
lessons-learned is an instructions file published in the GitHub repository affaan-m/ECC (251,781 stars, last pushed today), licensed MIT. It adds 671 tokens to every session, about $0.0034 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-07.
Other instructions, from other repositories
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.