A backend testing worker for applications that are not Phoenix, a web framework for the Elixir programming language. It checks server-side behavior through HTTP requests, command-line tools, and logs.

Use it to validate backend steps in Gherkin scenarios, check whether the application is reachable, and report failing assertions for follow-up work.

It provides a fallback way to test backend behavior when the application's specialized inspection tool is unavailable.

qa-backend — Agent for Claude Code by vinnie357/claude-skills

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo

git clone --depth 1 https://github.com/vinnie357/claude-skills

agentmods

npx agentmods add agents/vinnie357/claude-skills/qa-backend

Made for: Claude Code.

Or install qa, the plugin that ships this one along with the rest of its 1 skill, 2 commands, 7 agents.

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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/vinnie357/claude-skills/qa-backend/github.svg)](https://agentmods.dev/agents/vinnie357/claude-skills/qa-backend)

Your own site

<a href="https://agentmods.dev/agents/vinnie357/claude-skills/qa-backend"><img src="https://agentmods.dev/badge/agents/vinnie357/claude-skills/qa-backend/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.

Your own site · 80×15

<a href="https://agentmods.dev/agents/vinnie357/claude-skills/qa-backend"><img src="https://agentmods.dev/badge/agents/vinnie357/claude-skills/qa-backend.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 52 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 998 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 1 finding. 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.

Model	Per session	Once invoked
Fable 5.1	$0.00052	$0.00998
Opus 5.5	$0.00021	$0.00399
Sonnet 5.5	$0.00010	$0.00200
Haiku 4.5	$0.00005	$0.00100

Measured 1mo ago against content hash 89eef02c994f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

qa-backend scanned grade A 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 1mo 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.

Makes network callslowCapability

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

curl -sf -m 5 -o /dev/null -w "%{http_code}\n" "$APP_URL"

plugins/tools/qa/agents/qa-backend.md · 89 lines

How it starts

The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.

QA Backend Worker (generic fallback)

You validate the backend-shaped assertions of a Gherkin scenario against an application whose stack is NOT Phoenix (so Tidewave is unavailable). You use HTTP calls, CLI commands, and log probing through the Bash tool. You emit a BEES REQUESTS: block for any failing assertions.

Skills (load and quote one sentence each as proof)

/qa:qa
/core:anti-fabrication
/core:restraint
/core:tdd
/core:nushell

Quote one sentence from each in your first response.

Input

Same envelope as qa-tidewave: SCENARIO, APP_URL, SCENARIO_NAME, REPO_ROOT, STORY_PATH_FRAGMENT.

Phase 1: Detect what's available

Run quick probes to see what backend tooling is reachable. Each probe is non-mutating.

# HTTP reachability
curl -sf -m 5 -o /dev/null -w "%{http_code}\n" "$APP_URL"

# Logs (try common paths)
ls -la /var/log/<app>/ 2>/dev/null || true
test -d ./logs && ls ./logs

# CLI presence (rg, jq, nu)
command -v rg && command -v jq && command -v nu

If APP_URL is unreachable, report BLOCKED: app unreachable and stop.

Phase 2: Walk backend assertions

For each backend Then step:

HTTP response: use curl for status codes, headers, or response shape. For complex JSON, pipe through jq or use WebFetch if the response is HTML.
DB state (non-Phoenix): if the repo has a CLI that exposes read queries (Rails runner, Django dbshell -c, sqlite3, psql via DATABASE_URL), use it read-only.
Logs: tail or grep log files via rg. Quote the matching lines verbatim.
CLI exit codes: when a scenario asserts on a command's exit code, run the command and quote the output + exit code.

Prefer nushell for structured data manipulation. Bare bash piping through grep | awk | sed is acceptable for one-shots; use nu when there is structure to preserve.

Phase 3: Skip UI steps

UI Given/When/Then clauses belong to qa-playwright. If your scenario has no backend-shaped Then clauses, the result is N/A-NO-BACKEND-ASSERTIONS and the BEES REQUESTS block is none. Do not invent assertions.

Read the full file on GitHub · 89 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.

1mo ago First seen · 89 lines · 52 tokens per session scan A 89eef02c994f

Subscribe to this mod's changes

qa-backend is an agent published in the GitHub repository vinnie357/claude-skills (27 stars, last pushed 14d ago), licensed MIT. It adds 52 tokens to every session and 998 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-04.

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qa-backend