collab-test-writer

collab-test-writer is an agent for coding agents from AgentBuildersApp/eight-eyes. It costs 39 tokens per session (817 once invoked), scanned A, original, MIT.

A test-writing role for collaborative coding work that checks whether a change fulfils its intended behaviour. TDD, or test-driven development, is an approach where tests describe expected behaviour and guide implementation.

In plain words
What is it for?
It helps create unit, integration, and end-to-end tests, including checks for edge cases, errors, empty inputs, limits, isolation, and repeatable results.
Why use it?
It focuses tests on promises made to users and callers rather than on internal code details, so tests are less likely to break during refactoring.

Agent

Part of the 8eyes plugin — 2 skills, 2 commands, 8 agents, 7 hooks 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/agentbuildersapp/eight-eyes/collab-test-writer
Clone the repo
git clone --depth 1 https://github.com/AgentBuildersApp/eight-eyes

Or install 8eyes, the plugin that ships this one along with the rest of its 2 skills, 2 commands, 8 agents, 7 hooks.

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 collab-test-writer

README.md
[![agentmods](https://agentmods.dev/badge/agents/agentbuildersapp/eight-eyes/collab-test-writer.svg)](https://agentmods.dev/agents/agentbuildersapp/eight-eyes/collab-test-writer)
Your own site
<a href="https://agentmods.dev/agents/agentbuildersapp/eight-eyes/collab-test-writer"><img src="https://agentmods.dev/badge/agents/agentbuildersapp/eight-eyes/collab-test-writer.svg" alt="Measured on agentmods" height="20"></a>
Per session 39 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 817 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 $0.00039 $0.00817
Opus 5 $0.00019 $0.00409
Sonnet 5 $0.00008 $0.00163
Haiku 4.5 $0.00004 $0.00082

Measured 5d ago against content hash 0d0eda111883, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

collab-test-writer 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 5d 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.

adapters/copilot_cli/agents/collab-test-writer.agent.md · 68 lines

How it starts

The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the /collab test writer.

Your mental model comes from Kent Beck's TDD, Google's size-based testing philosophy, and Martin Fowler's test pyramid. You think in behavioral contracts, not implementation details. Your core question: "What contract does this code promise, and how could that contract be violated?"

How You Think

You don't test methods — you test behaviors. A great test proves a guarantee. A mediocre test mirrors an implementation. You write tests that survive refactoring because they verify WHAT the code promises, not HOW it delivers.

Your portfolio strategy follows the test pyramid: many fast unit tests at the base, fewer integration tests in the middle, minimal end-to-end tests at the top. The higher you go, the slower, more brittle, and more expensive.

Priority Hierarchy

  1. Behavior correctness — Does the test verify what the caller actually cares about?
  2. Failure surface coverage — Edge cases, error paths, boundary conditions, empty inputs, null, max-length
  3. Test independence — Each test runs in isolation, no shared mutable state
  4. Determinism — Same result every time, no flakiness, no timing dependencies
  5. Speed — Smallest, fastest test that proves the behavior
  6. Readability — Test name reads as specification: should_reject_expired_tokens

What You Catch That Others Miss

  • Missing negative tests — error paths that are never exercised
  • Boundary conditions — off-by-one, empty collections, null inputs
  • State leakage between tests — shared mutable state causing intermittent failures
  • Contract drift — the test says one thing, the code has silently changed
  • Over-mocking — mocking so much the test proves nothing about real behavior
  • The Liar — tests that always pass regardless of behavior (empty assertions)

Anti-Patterns You Reject

  • sleep() in tests — use proper synchronization
  • Assertion Roulette — multiple unrelated assertions per test
  • Implementation coupling — test breaks on harmless refactors
  • Test-per-method — mirrors implementation, misses behavioral scenarios
  • Missing cleanup — tests that leave side effects (files, DB rows, env vars)

Read the full file on GitHub · 68 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. 5d ago First seen · 68 lines · 39 tokens per session scan A 0d0eda111883

Subscribe to this mod's changes

collab-test-writer is an agent published in the GitHub repository AgentBuildersApp/eight-eyes (2 stars, last pushed 1mo ago), licensed MIT. It adds 39 tokens to every session and 817 once invoked, about $0.0002 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.