agentmods.dev

underpixel CLAUDE.md

Project instructions for UnderPixel, a monorepo containing a Chrome extension, a local bridge server, and shared packages. A monorepo is one repository that contains several related projects.

In plain words
What is it for?
Use them when developing UnderPixel, especially when installing dependencies, building packages, running tests or linting, or changing network capture and shared types.
Why use it?
They document the project’s build, test, and design conventions, including details that are easy to break when changing browser or server code.

Instructions file

0 4mo ago A scan 457 tokens original MIT
View the source file Leluth/underpixel
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/leluth/underpixel/claude-md
Clone the repo
git clone --depth 1 https://github.com/Leluth/underpixel
Per session 457 This file is loaded in full into every session.
When invoked 457 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.

ModelPer sessionOnce invoked
Fable 5 $0.00457 $0.00457
Opus 5 $0.00229 $0.00229
Sonnet 5 $0.00091 $0.00091
Haiku 4.5 $0.00046 $0.00046

Measured yesterday against content hash dce510bf650c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

underpixel 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 · 34 lines

What it actually says

UnderPixel

Chrome extension + MCP server for visual-API correlation. Monorepo: extension/ (Chrome MV3, WXT), bridge/ (Native Messaging + Fastify MCP server), packages/shared/ (types, constants, tool schemas).

Commands

pnpm install          # from root
pnpm build            # builds all (shared → bridge → extension)
pnpm dev              # WXT dev mode with HMR
pnpm test             # vitest across all packages
pnpm lint             # ESLint
pnpm format:check     # Prettier check

Workflow

  • Run pnpm lint and pnpm test before reporting done.
  • Don't commit/push unless explicitly asked.

Non-obvious conventions

  • Network capture requires chrome.debugger (CDP) — chrome.webRequest cannot read response bodies.
  • rrweb runs in MAIN world content script, bridged to ISOLATED world via window.postMessage — rrweb needs real DOM access but chrome.runtime only works in ISOLATED world.
  • Response bodies stored inline if <100KB, otherwise in separate responseBodies IDB store via responseBodyRef. Don't change these thresholds without updating both capture.ts and api_calls tool.
  • Don't modify packages/shared/src/types.ts lightly — both extension and bridge depend on it.
  • Replay UI uses Svelte 5 in legacy mode (Svelte 4 syntax). If migrating to runes, convert all components in one pass.
  • Svelte 4 store caveat — $store.anyProp subscribes to the entire store. Avoid reading $replayStore in reactive blocks that don't need currentTime (fires at 60Hz).
  • rrweb inlineImages: false — broken in this alpha (rrweb-io/rrweb#1218). Causes seek crashes on cross-origin-heavy pages. Enable when fixed.

Design docs

See docs/ — includes high-level vision, tech design, and per-feature specs/plans in docs/superpowers/.

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. yesterday First seen · 34 lines · 457 tokens per session scan A dce510bf650c

Subscribe to this mod's changes

underpixel CLAUDE.md is an instructions file published in the GitHub repository Leluth/underpixel (0 stars, last pushed 4mo ago), licensed MIT. It adds 457 tokens to every session, about $0.0023 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 2026-08-31.

api-monitoringbrowser-automationchrome-extensionclaude-codedeveloper-toolsdevtools
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