symphony-rust: Skill for Claude Code

.agents/skills/symphony-screenshot/SKILL.md

symphony-screenshot is a skill for Claude Code, Codex from anantjain-xyz/symphony-rust. It costs 52 tokens per session (4,287 once invoked), scanned C, original, MIT.

A workflow for capturing Playwright screenshots of user-facing changes and adding them to a GitHub pull request as testing evidence.

In plain words
What is it for?
Taking screenshots of pages, including authenticated pages and interactive states, adding their links to a pull request description, and then cleaning up the temporary screenshot files.
Why use it?
It provides visual proof that a change was tested while keeping the screenshot files out of the branch’s final state.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is anantjain-xyz/symphony-rust's own configuration. It tells Claude Code and Codex how to work on symphony-rust itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything symphony-rust configures →

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is // Usage: node .symphony/capture.mjs <spec.json>.

Reuse

Borrowing it

Nothing to install: this file belongs to anantjain-xyz/symphony-rust. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/anantjain-xyz/symphony-rust/main/.agents/skills/symphony-screenshot/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/anantjain-xyz/symphony-rust

Made for: Claude Code, Codex.

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 symphony-screenshot

README.md
[![agentmods](https://agentmods.dev/badge/skills/anantjain-xyz/symphony-rust/symphony-screenshot/github.svg)](https://agentmods.dev/skills/anantjain-xyz/symphony-rust/symphony-screenshot)
Your own site
<a href="https://agentmods.dev/skills/anantjain-xyz/symphony-rust/symphony-screenshot"><img src="https://agentmods.dev/badge/skills/anantjain-xyz/symphony-rust/symphony-screenshot/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for symphony-screenshot

Your own site · 80×15
<a href="https://agentmods.dev/skills/anantjain-xyz/symphony-rust/symphony-screenshot"><img src="https://agentmods.dev/badge/skills/anantjain-xyz/symphony-rust/symphony-screenshot.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,287 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 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 $0.00052 $0.04287
Opus 5 $0.00026 $0.02143
Sonnet 5 $0.00010 $0.00857
Haiku 4.5 $0.00005 $0.00429

Measured 11d ago against content hash f5279a9c3dd7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade C, and why

symphony-screenshot scanned grade C with 2 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 11d 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.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

8. **Cleanup workspace artifacts**: `rm -rf .symphony/screenshots .symphony/capture.mjs .playwright-mcp` and `rm -f .symphony/screenshot-sha /tmp/symphony-shots.json` (those should not appear in `git status` afterward).

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

6. **Verify the images render** in the PR (visual confirmation by the operator, or a `curl -I "$raw_url"` returning 200 if running unattended). Do not proceed to step 7 without confirmation — the cleanup revert removes t
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.agents/skills/symphony-screenshot/SKILL.md · 265 lines

How it starts

The opening of the file, as written. The whole thing — 265 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Screenshot

The PR description is the home for proof-of-testing screenshots. They are hosted as raw GitHub blobs at the screenshot commit SHA. After the PR body is updated, create a follow-up revert commit that removes the screenshot files from the branch tip while keeping the original screenshot commit reachable in branch history.

Capture runs through a small Node script (capture.mjs) driven from the shell, not the Playwright MCP. The MCP's browser_run_code_unsafe runs in a sandbox with no process, require, or context, so it cannot read an environment variable or inject a session cookie — authenticated dev captures are impossible there. A plain Node script gets a normal process.env, so a session cookie can be injected while the secret stays in the environment and never appears in a tool call / transcript. The script also bypasses self-signed dev certs, handles SPAs that never reach network-idle, fails on unexpected HTTP statuses, and can run interactions (hover/click/…) to reach states that aren't a bare URL.

Preconditions

  • A PR exists for the current branch (use the symphony-push skill first if not).
  • gh auth status succeeds against the repo's host, and plain git push has credentials for that host. If relying on GitHub CLI for HTTPS git credentials, run gh auth setup-git first (gh auth setup-git --hostname <host> for a non-default host). GITHUB_TOKEN/GH_TOKEN alone can authenticate gh pr ... commands but is not enough for the git push origin ... and git push --force-with-lease ... commands this workflow runs.
  • Playwright is installed in the repo's node_modules. capture.mjs does import { chromium } from 'playwright', resolved from the repo tree. If the repo doesn't already depend on Playwright, install it first (npm install --no-save playwright, or the repo's package manager) — npx playwright does not make the bare import resolvable for a plain node .symphony/capture.mjs. If it can't be installed, surface a blocker rather than guessing.
  • For authenticated targets only (anything behind a login wall, e.g. a dev server): the session cookie value must be present in an environment variable (do not hardcode it). You pass the env var's name and the cookie's name/domain in the spec — never the value. If the var is unset, stop and surface a blocker; do not capture the auth wall.

Read the full file on GitHub · 265 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. 11d ago First seen · 265 lines · 52 tokens per session scan C f5279a9c3dd7

Subscribe to this mod's changes

symphony-screenshot is a skill published in the GitHub repository anantjain-xyz/symphony-rust (11 stars, last pushed 28d ago), licensed MIT. It adds 52 tokens to every session and 4,287 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it C with 2 findings (recursive force delete, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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