bun-file

bun-file is a cursor rule for Cursor from takuya0206/slack_search_function_mcp. It costs 2,169 tokens per session, scanned C, original, no licence file.

A Cursor rule describing how to read, delete, and write files with Bun, a JavaScript runtime. It also covers incremental writing and directories.

In plain words
What is it for?
Use it when an agent needs to inspect files, remove files, create or update files, or write data incrementally in a Bun project.
Why use it?
It gives the coding agent file-operation instructions for projects that use Bun, so those operations follow the stated approach.

Cursor rule for Cursor

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 rules/takuya0206/slack_search_function_mcp/bun-file
Clone the repo
git clone --depth 1 https://github.com/takuya0206/slack_search_function_mcp

Made for: Cursor.

Wrote 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.

agentmods badge for bun-file

README.md
[![agentmods](https://agentmods.dev/badge/rules/takuya0206/slack_search_function_mcp/bun-file.svg)](https://agentmods.dev/rules/takuya0206/slack_search_function_mcp/bun-file)
Your own site
<a href="https://agentmods.dev/rules/takuya0206/slack_search_function_mcp/bun-file"><img src="https://agentmods.dev/badge/rules/takuya0206/slack_search_function_mcp/bun-file.svg" alt="Measured on agentmods" height="20"></a>
Per session 2,169 This file is loaded in full into every session.
When invoked 2,169 The same file — it is already loaded in full.
Security scan C 1 finding. Scan, not verified.
Origin unknown 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.

ModelPer sessionOnce invoked
Fable 5 $0.02169 $0.02169
Opus 5 $0.01085 $0.01085
Sonnet 5 $0.00434 $0.00434
Haiku 4.5 $0.00217 $0.00217

Measured 4d ago against content hash 46bab1907fd6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

bun-file scanned grade C with 1 finding 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 4d 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.

Hidden instructionshighPrompt injection

Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.

<!-- **Note** — The `Bun.file` and `Bun.write` APIs documented on this page are heavily optimized and represent the recommended way to perform file-system tasks using Bun. Existing Node.js projects may use Bun's [nearly
.cursor/rules/bun-file.mdc · 369 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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.

  1. 4d ago First seen · 369 lines · 2,169 tokens per session scan C 46bab1907fd6

Subscribe to this mod's changes

bun-file is a cursor rule published in the GitHub repository takuya0206/slack_search_function_mcp (4 stars, last pushed 1y ago), with no licence file. It adds 2,169 tokens to every session, about $0.0108 per session on Opus 5. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.