tempest CLAUDE.md

tempest CLAUDE.md is an instructions file for coding agents from MattFlower/tempest. It costs 893 tokens per session, scanned B, original, MIT.

A repository guidance document for Tempest, a macOS developer tool built with TypeScript, React, and Electrobun. It explains the app’s two-process design, technology choices, and special dependency requirements.

In plain words
What is it for?
Use it when modifying Tempest’s Electrobun integration, Bun backend, React interface, terminal, native webview behavior, or fork-specific documentation.
Why use it?
It helps coding agents understand how the backend, web interface, terminal, and native webview fit together before changing the project.

Instructions file

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/mattflower/tempest/claude-md
Clone the repo
git clone --depth 1 https://github.com/MattFlower/tempest

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 tempest CLAUDE.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/mattflower/tempest/claude-md.svg)](https://agentmods.dev/instructions/mattflower/tempest/claude-md)
Your own site
<a href="https://agentmods.dev/instructions/mattflower/tempest/claude-md"><img src="https://agentmods.dev/badge/instructions/mattflower/tempest/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 893 This file is loaded in full into every session.
When invoked 893 The same file — it is already loaded in full.
Security scan B 1 finding. 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.

ModelPer sessionOnce invoked
Fable 5 $0.00893 $0.00893
Opus 5 $0.00447 $0.00447
Sonnet 5 $0.00179 $0.00179
Haiku 4.5 $0.00089 $0.00089

Measured 4d ago against content hash 540e2abc8ddc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

tempest CLAUDE.md scanned grade B 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.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

| Per-session MCP tool injection (`show_webpage`, `show_mermaid_diagram`, `show_markdown`) | Yes (`--mcp-config`) | — | **No** — Codex reads MCP from `~/.codex/config.toml` globally |
CLAUDE.md · 67 lines

How it starts

The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tempest — Electrobun Rewrite

Overview

Tempest is a macOS developer tool rewritten from Swift/SwiftUI to Electrobun/TypeScript. Two-process architecture: Bun backend + React webview frontend, communicating via typed RPC.

Tech Stack

  • Framework: Electrobun (private fork, see below) — Bun + native WebView.
  • UI: React 19 + Tailwind CSS 4 + Zustand
  • Terminal: xterm.js 6 with WebGL renderer + Bun.Terminal PTY
  • Browser: System webview (WKWebView on macOS) via <electrobun-webview>

Forked Electrobun

The electrobun dependency in package.json is not the published npm package. It's a tarball URL pointing at a release on MattFlower/electrobun (branch auto-mask-overlays, local checkout at ~/code/electrobun). The fork is rebased on upstream v1.18.1 and adds two things Tempest relies on: an auto-mask attribute on <electrobun-webview> for popups over native browser panes, and a re-sync bugfix in OverlaySyncController. (Traffic-light positioning via setWindowButtonPosition was previously a fork patch but has since landed in upstream — Tempest now consumes it directly.)

Read AI_DOCS/electrobun-fork.md before changing anything that touches <electrobun-webview>, the bun-side electrobun APIs, or the native window chrome — and before answering questions about how the electrobun dependency is wired. Cutting a new fork release uses the runbook at ~/code/electrobun/RELEASING-TEMPEST-FORK.md.

Key Architectural Rules

  1. Terminal lifecycle: Never unmount terminal components on tab switch. Use opacity-0 + pointer-events-none.
  2. PaneNode is immutable: All tree operations return new trees.
  3. RPC hot path: Terminal I/O uses fire-and-forget messages. Base64 encode PTY data. Sequence numbers for ordering.
  4. Microtask coalescing: PTY output batched via queueMicrotask.

Coding Agents

Tempest supports three terminal-hosted coding agents. Their integration depth differs because each CLI exposes different extension points.

Read the full file on GitHub · 67 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.

  1. 4d ago First seen · 67 lines · 893 tokens per session scan B 540e2abc8ddc

Subscribe to this mod's changes

tempest CLAUDE.md is an instructions file published in the GitHub repository MattFlower/tempest (7 stars, last pushed 26d ago), licensed MIT. It adds 893 tokens to every session, about $0.0045 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.