tester

tester is an agent for coding agents from vosslab/vosslab-skills. It costs 15 tokens per session (214 once invoked), scanned A, original, MIT.

A testing agent that writes tests, expands test coverage, and checks whether software still behaves correctly after changes. Test coverage describes how much of the code's behavior is exercised by tests.

In plain words
What is it for?
Use it to create or extend tests, run the project's test suite, report failures and affected files, and identify when a project lacks a documented test command.
Why use it?
It helps detect regressions, which are new failures caused by a change that breaks behavior that previously worked.

Agent

Part of the vosslab-skills plugin — 42 skills, 14 agents shipped together

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 agents/vosslab/vosslab-skills/tester
Clone the repo
git clone --depth 1 https://github.com/vosslab/vosslab-skills

Or install vosslab-skills, the plugin that ships this one along with the rest of its 42 skills, 14 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.

agentmods badge for tester

README.md
[![agentmods](https://agentmods.dev/badge/agents/vosslab/vosslab-skills/tester.svg)](https://agentmods.dev/agents/vosslab/vosslab-skills/tester)
Your own site
<a href="https://agentmods.dev/agents/vosslab/vosslab-skills/tester"><img src="https://agentmods.dev/badge/agents/vosslab/vosslab-skills/tester.svg" alt="Measured on agentmods" height="20"></a>
Per session 15 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 214 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 $0.00015 $0.00214
Opus 5 $0.00008 $0.00107
Sonnet 5 $0.00003 $0.00043
Haiku 4.5 $0.00002 $0.00021

Measured 4d ago against content hash 60d97ffd975e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tester 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.

agents/tester.md · 23 lines

What it actually says

Write and run tests for code produced by coders. Only create or edit files under tests/; do not modify production code. Run the repo's standard test command as documented by the project. If no test entrypoint is documented, report the missing test entrypoint.

Detect regressions by running the full test suite after changes. Report failures with output and affected file paths via task updates.

Follow docs/REPO_STYLE.md on every task. When the task involves Python, also follow docs/PYTHON_STYLE.md and docs/PYTEST_STYLE.md. When a skill dispatches you with repo-rules-reader output, treat that output as the current source of truth for repo rules.

Escalation paths:

  • Production bug found -> coder
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 · 23 lines · 15 tokens per session scan A 60d97ffd975e

Subscribe to this mod's changes

tester is an agent published in the GitHub repository vosslab/vosslab-skills (2 stars, last pushed 9d ago), licensed MIT. It adds 15 tokens to every session and 214 once invoked, about $0.0001 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.