What is deno CLAUDE.md?

Development instructions for Deno, a JavaScript and TypeScript runtime, used with Claude Code. They explain the project’s layout, commands, testing, formatting, and pull-request process.

They are for navigating Deno’s codebase, running the right formatters and tests, debugging changes, and preparing commits and pull requests.

They give an agent the repository context and required workflow needed to make changes that fit the project.

deno CLAUDE.md — Instructions file by denoland

Install

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.

agentmods

npx agentmods add instructions/denoland/deno/claude-md

Clone the repo

git clone --depth 1 https://github.com/denoland/deno

Per session 2,993 This file is loaded in full into every session.

When invoked 2,993 The same file — it is already loaded in full.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

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	$0.02993	$0.02993
Opus 5	$0.01496	$0.01496
Sonnet 5	$0.00599	$0.00599
Haiku 4.5	$0.00299	$0.00299

Measured yesterday against content hash 69015aad5ec6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

deno 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 yesterday.

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.

CLAUDE.md · 434 lines

How it starts

The opening of the file, as written. The whole thing — 434 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Git workflow

Deno uses a GH based standard git workflow. The main branch is main. All development happens in feature branches, which are then merged into main via pull requests.

When the feature is finished and ready to for review, follow these steps:

Create a new git branch, if you haven't already, with a descriptive name (e.g., feature/new-cli-command or fix/bug-in-worker-threads).
Commit your changes with clear and descriptive commit messages.
Push your branch to the remote repository.
Open a pull request (PR) against the main branch on GitHub.
Before committing, make sure tools/format.js is run to format your code
Before committing, if only non-Rust was changed, make sure to run tools/lint.js --js and fix any lint errors before committing
If you changed Rust code, make sure to run tools/lint.js and fix any lint errors before committing
In the PR description, provide a clear summary of the changes you made, why they were necessary, and any relevant context or links to related issues.
When pushing updates to the PR, make sure to never force push. Create as many commits as you need, all of them get squashed when the PR is merged, so there is no need to rewrite history. This also allows reviewers to see the incremental changes you made in response to feedback.
Keep your changes minimal, don't do drive-by changes in a PR. If you need to make a change that is not directly related to the PR, create a separate PR for it. This keeps the review process focused and efficient.

High Level Overview

The user visible interface and high level integration is in the deno crate (located in ./cli).

Read the full file on GitHub · 434 lines

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.

yesterday First seen · 434 lines · 2,993 tokens per session scan A 69015aad5ec6

Subscribe to this mod's changes

deno CLAUDE.md is an instructions file published in the GitHub repository denoland/deno (108,342 stars, last pushed 2d ago), licensed MIT. It adds 2,993 tokens to every session, about $0.0150 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.

Debugging Git and workflow Testing deno javascript rust typescript

deno CLAUDE.md

Getting it into your agent

What it costs to keep this loaded

Grade A, and why

Nothing flagged

How it starts

Deno Development Guide

Table of Contents

Git workflow

High Level Overview

What this file has done since we first saw it

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