gsd-browser

gsd-browser is a skill for Claude Code from gsd-build/gsd-browser. It costs 138 tokens per session (1,198 once invoked), scanned A, original, Apache-2.0.

A command-line browser automation tool written in Rust for navigating websites and interacting with their pages. It can read page structure, perform actions, take screenshots, and check results.

In plain words
What is it for?
Use it to test web apps, fill forms, click controls, extract information, take screenshots, inspect pages, mock network requests, and share or narrate browser activity.
Why use it?
It lets an AI agent carry out and verify browser tasks through repeatable commands instead of relying on manual clicking.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to test web apps, fill forms, click controls, extract information, take screenshots, inspect pages, mock network requests, and share or narrate browser activity.

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Install with agentmods
npx agentmods add skills/gsd-build/gsd-browser/gsd-browser-skill
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.

Any agent
npx skills add gsd-build/gsd-browser --skill gsd-browser-skill
Clone the repo
git clone --depth 1 https://github.com/gsd-build/gsd-browser

Made for: Claude Code.

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 gsd-browser

README.md
[![agentmods](https://agentmods.dev/badge/skills/gsd-build/gsd-browser/gsd-browser-skill.svg)](https://agentmods.dev/skills/gsd-build/gsd-browser/gsd-browser-skill)
Your own site
<a href="https://agentmods.dev/skills/gsd-build/gsd-browser/gsd-browser-skill"><img src="https://agentmods.dev/badge/skills/gsd-build/gsd-browser/gsd-browser-skill.svg" alt="Measured on agentmods" height="20"></a>
Per session 138 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,198 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00138 $0.01198
Opus 5 $0.00069 $0.00599
Sonnet 5 $0.00028 $0.00240
Haiku 4.5 $0.00014 $0.00120

Measured 8d ago against content hash 8cb289ec972c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

gsd-browser 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 8d 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.

gsd-browser-skill/SKILL.md · 107 lines

How it starts

The opening of the file, as written. The whole thing — 107 lines — stays where its author put it; the contents beside it link to each section on GitHub.

<essential_principles>

The daemon auto-starts on browser commands. gsd-browser daemon health reports state and does not start a session. Use gsd-browser daemon start only when you want to pre-warm or verify daemon lifecycle explicitly.

Always re-snapshot after page changes. Refs are versioned (@v1:e1, @v2:e3). After navigation, form submission, or dynamic content loading, old refs are stale. Run gsd-browser snapshot to get fresh refs before interacting.

Use --json when parsing output. Use text mode when reading output yourself. Use --json when you need to extract values programmatically.

Positional args have no flag prefix. Commands like click, type, hover take positional args. Do NOT add --selector:

  • gsd-browser click "button.submit" (correct)
  • gsd-browser click --selector "button.submit" (WRONG)

Core workflow pattern: Every browser automation follows: navigate -> snapshot -> interact -> re-snapshot (after DOM changes).

gsd-browser navigate https://example.com
gsd-browser snapshot
# Read snapshot output: @v1:e1 [input type="email"], @v1:e2 [button] "Submit"
gsd-browser fill-ref @v1:e1 "[email protected]"
gsd-browser click-ref @v1:e2
gsd-browser wait-for --condition network_idle
gsd-browser snapshot  # REQUIRED - old refs are now stale

Command chaining: Use && when you don't need intermediate output. Run separately when you need to parse output first (e.g., snapshot to discover refs, then interact).

Use the live viewer when the user wants to watch or direct the browser. gsd-browser view opens a localhost viewer with live frames, narrated action history, ref overlays, and pause/step/resume/abort controls. Keep using CLI commands for actions; the viewer is the shared screen and control surface.

Global options available on all commands:

Flag Purpose
--json Structured JSON output
--browser-path <path> Path to Chrome/Chromium
--cdp-url <url> Attach to an already-running Chrome instance
--session <name> Named session for parallel instances
--no-narration-delay Skip narration lead-time sleeps while keeping history/events

</essential_principles>

Based on what the user needs, read the appropriate workflow:

User intent Workflow
Navigate, click, type, fill forms, interact with pages workflows/navigate-and-interact.md
Share the browser screen, narrate actions, pause/step/resume/abort workflows/live-viewer-and-narration.md
Scrape data, extract content, read page structure workflows/scrape-and-extract.md
Test pages, run assertions, visual regression, mock network workflows/test-and-assert.md
Debug issues, check logs, diagnose problems workflows/debug-and-diagnose.md
Install, configure, set up sessions workflows/setup-and-configure.md

After reading the workflow, follow it. Load references only when the workflow directs you to.

<reference_index>

All domain knowledge in references/:

Commands: command-reference.md (complete command syntax) Snapshots: snapshot-and-refs.md (versioned refs, snapshot modes) Intents: semantic-intents.md (15 predefined intents for find-best/act) Errors: error-recovery.md (common errors and fixes) Config: configuration.md (TOML config, env vars, 5-layer merge)

</reference_index>

<workflows_index>

Workflow Purpose
navigate-and-interact.md Page navigation, clicking, typing, forms, intents
live-viewer-and-narration.md Live shared viewer, narrated history, refs overlay, controls
scrape-and-extract.md Data extraction, accessibility tree, page source
test-and-assert.md Assertions, visual regression, network mocking, test generation
debug-and-diagnose.md Console/network logs, timeline, debug bundles
setup-and-configure.md Installation, configuration, sessions, daemon management

Read the full file on GitHub · 107 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. 8d ago First seen · 107 lines · 138 tokens per session scan A 8cb289ec972c

Subscribe to this mod's changes

gsd-browser is a skill published in the GitHub repository gsd-build/gsd-browser (264 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 138 tokens to every session and 1,198 once invoked, about $0.0007 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.

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