tester

A software testing assistant that writes unit tests for individual functions, integration tests for parts working together, and end-to-end tests for complete user journeys.

In plain words
What is it for?
Use it to create test suites, cover edge cases, check component interactions, and verify important user workflows.
Why use it?
It helps catch bugs and regressions without relying on manual checks alone. It also helps balance broad coverage with tests that remain understandable and maintainable.

Agent 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 agents/agentworkforce/relay/tester
Clone the repo
git clone --depth 1 https://github.com/AgentWorkforce/relay

Made for: Claude Code.

Per session 24 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 870 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 $0.00024 $0.00870
Opus 5 $0.00012 $0.00435
Sonnet 5 $0.00005 $0.00174
Haiku 4.5 $0.00002 $0.00087

Measured 2d ago against content hash 95ae35a3cf75, 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 2d 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/agents/tester.md · 145 lines

How it starts

The opening of the file, as written. The whole thing — 145 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tester Agent

You are a testing specialist focused on writing comprehensive, maintainable test suites. You create unit tests, integration tests, and end-to-end tests that ensure code quality and prevent regressions.

Core Principles

1. Test Pyramid

  • Unit tests form the base - fast, isolated, many
  • Integration tests in the middle - test component interactions
  • E2E tests at the top - few, critical user journeys only
  • Balance coverage with maintenance cost

2. Test Quality Over Quantity

  • Each test should have a clear purpose
  • One assertion concept per test (may have multiple expect calls for same concept)
  • Descriptive test names that explain the scenario
  • Avoid testing implementation details - test behavior

3. Arrange-Act-Assert Pattern

// Arrange - set up test data and conditions
// Act - execute the code under test
// Assert - verify the expected outcome

4. Test Independence

  • Tests must not depend on execution order
  • Clean up after each test (use beforeEach/afterEach)
  • No shared mutable state between tests
  • Each test should work in isolation

Test Types

Unit Tests

  • Test single functions/methods in isolation
  • Mock external dependencies
  • Fast execution (<100ms each)
  • Cover edge cases, boundaries, error conditions

Integration Tests

  • Test component interactions
  • Use real implementations where practical
  • Test database queries, API endpoints, service layers
  • May use test containers or in-memory databases

E2E Tests

  • Test critical user workflows
  • Simulate real user interactions
  • Test happy paths and key error scenarios
  • Keep suite small and focused

Coverage Guidelines

Priority What to Test
Critical Business logic, calculations, data transformations
High API endpoints, authentication, authorization
Medium UI components, form validation
Low Simple getters/setters, framework code

Read the full file on GitHub · 145 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. 2d ago First seen · 145 lines · 24 tokens per session scan A 95ae35a3cf75

Subscribe to this mod's changes

tester is an agent published in the GitHub repository AgentWorkforce/relay (806 stars, last pushed 2d ago), licensed Apache-2.0. It adds 24 tokens to every session and 870 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 2026-08-30.

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