Borrowing it
Nothing to install: this file belongs to fastslack/kernl. 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/fastslack/kernl/stable/CLAUDE.mdgit clone --depth 1 https://github.com/fastslack/kernlWrote 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/fastslack/kernl/claude-md)<a href="https://agentmods.dev/instructions/fastslack/kernl/claude-md"><img src="https://agentmods.dev/badge/instructions/fastslack/kernl/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/fastslack/kernl/claude-md"><img src="https://agentmods.dev/badge/instructions/fastslack/kernl/claude-md.svg" alt="Reviewed on agentmods" width="80" 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 | $0.01926 | $0.01926 |
| Opus 5.5 | $0.00770 | $0.00770 |
| Sonnet 5.5 | $0.00385 | $0.00385 |
| Haiku 4.5 | $0.00193 | $0.00193 |
Grade A, and why
kernl CLAUDE.md 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.
export function createFooModule(): KernelModule {
let tools: ToolDefinition[] = [];
return {
name: "foo",
async initialize(ctx: ModuleContext) {
runMigrations(ctx.sqlite, "foo", fooMigrations); // if has tables
const service = new FooService(ctx.sqlite, ctx.neo4j);
tools = fooTools(service);
},
getTools() { return tools; },
async shutdown() {},
};
}
ModuleContext: { sqlite, neo4j, events, config }
Migrations use Migration { version: number; sql: string } arrays, located in:
services/kernel/src/modules/{name}/migrations/*.ts(directory pattern), orservices/kernel/src/modules/{name}/migrations.ts(inline pattern)
SQLite NOT NULL columns with empty defaults:
contacts table: email, phone, company, notes are NOT NULL DEFAULT ''.
Use <> '' to check for presence, NOT IS NOT NULL.
Same pattern used in many other tables (communications, events, etc.)
Google sync source column:
source column lives in google_sync_map table, NOT in contacts — join via local_id = contacts.id.
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.
- 1mo ago Changed · +4 lines · +81 tokens per session f589b214976b
- 2mo ago First seen · 146 lines · 1,845 tokens per session scan A 834ac199c733
kernl CLAUDE.md is an instructions file published in the GitHub repository fastslack/kernl (3 stars, last pushed yesterday), licensed Apache-2.0. It adds 1,926 tokens to every session, about $0.0077 per session on Opus 5.5. 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 2026-08-31.
kernl CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| kernl CLAUDE.mdfastslack/kernl | Instructions file | 3 | yesterday | Apache-2.0 | A | 1,926 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | yesterday | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |