Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/ccashwell/evm-cortex/hook-developmentgit clone --depth 1 https://github.com/ccashwell/evm-cortexWhat 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 | $0.00264 | $0.00264 |
| Opus 5 | $0.00132 | $0.00132 |
| Sonnet 5 | $0.00053 | $0.00053 |
| Haiku 4.5 | $0.00026 | $0.00026 |
Grade A, and why
hook-development 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 2d ago.
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.
What it actually says
Hook Development Rules
Hook Architecture
Hooks are TypeScript files compiled to ESM bundles (.mjs) via esbuild.
Source: hooks/src/*.ts
Built: hooks/dist/*.mjs
Shared: hooks/src/shared/*.ts
When to Create Hooks
Hooks automate actions around agent events:
- Pre/post edit actions (run forge build, slither)
- Session lifecycle (start, end, compact)
- Memory and learning operations
- Security scanning (credential detection, SAST)
EVM-Specific Hook Patterns
forge-compile-check: Runforge buildafter .sol file editsslither-on-save: Run Slither after Solidity changesgas-snapshot-diff: Compare forge snapshots after editsnatspec-enforcer: Check NatSpec on public/external functionsstorage-layout-check: Validate storage layout for proxy contracts
Quality Rules
- Hooks must be fast (< 5 second execution)
- Never block on long-running operations
- Handle errors gracefully (log and continue)
- Keep hooks focused on one responsibility
- Use shared utilities from
hooks/src/shared/
Build
cd hooks && npm run build
Consider these rules if they affect your changes.
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.
- 2d ago First seen · 39 lines · 264 tokens per session scan A 7326c6896bd4
hook-development is a cursor rule published in the GitHub repository ccashwell/evm-cortex (127 stars, last pushed 22d ago), licensed MIT. It adds 264 tokens to every session, about $0.0013 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 2026-08-30.
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