dev-screenshot

dev-screenshot is a command for Claude Code from cdknorow/coral. It costs 0 tokens per session (318 once invoked), scanned A, original, Apache-2.0.

A development command for rebuilding a Go server, opening its interface in a browser, and saving a screenshot. The isolated setup is intended for checking visual changes during development.

In plain words
What is it for?
Use it in a repeatable edit-and-check loop: change the UI, run the command, inspect /tmp/coral-screenshot.png, and stop the temporary server when finished.
Why use it?
It makes it easier to see whether CSS or HTML changes match the intended design without using the main app’s server or data directory.

Command for Claude Code

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 commands/cdknorow/coral/dev-screenshot
Clone the repo
git clone --depth 1 https://github.com/cdknorow/coral

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 dev-screenshot

README.md
[![agentmods](https://agentmods.dev/badge/commands/cdknorow/coral/dev-screenshot.svg)](https://agentmods.dev/commands/cdknorow/coral/dev-screenshot)
Your own site
<a href="https://agentmods.dev/commands/cdknorow/coral/dev-screenshot"><img src="https://agentmods.dev/badge/commands/cdknorow/coral/dev-screenshot.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 318 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00000 $0.00318
Opus 5 $0.00000 $0.00159
Sonnet 5 $0.00000 $0.00064
Haiku 4.5 $0.00000 $0.00032

Measured 4d ago against content hash d8bfb54f09f7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dev-screenshot 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 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.

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/commands/dev-screenshot.md · 40 lines

What it actually says

Dev Screenshot: Build, Reload, and Capture UI

Use the dev screenshot script to iterate on UI changes. This builds the Go server with dev tags, starts it on an isolated port, opens the browser, and captures a screenshot for visual verification.

Steps

  1. Run the dev screenshot script:
PATH="/usr/local/go/bin:$PATH" ./scripts/dev-screenshot.sh
  1. Wait for the script to complete (builds, starts server on port 8450, opens browser, takes screenshot)

  2. Read the screenshot to verify visual changes:

Read /tmp/coral-screenshot.png
  1. Compare against the reference design or previous screenshot. Note any issues.

  2. When done iterating, stop the dev server:

kill $(lsof -ti :8450) 2>/dev/null

Details

  • Port: 8450 (avoids conflicts with main app on 8420)
  • Data dir: /tmp/.coral-dev/ (fully isolated, won't touch ~/.coral/)
  • Build tags: -tags dev (skips EULA and license)
  • Screenshot: Saved to /tmp/coral-screenshot.png
  • Browser: Auto-opens and navigates to first available session

Usage Pattern for UI Iteration

  1. Make CSS/HTML changes
  2. Run /dev-screenshot to rebuild and capture
  3. Read the screenshot to verify
  4. Repeat until the UI matches the design
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 · 40 lines · 0 tokens per session scan A d8bfb54f09f7

Subscribe to this mod's changes

dev-screenshot is a command published in the GitHub repository cdknorow/coral (33 stars, last pushed 7d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 318 tokens. 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.