test-engineer

An automated test-writing and test-running agent. It follows the project's testing conventions and can write unit, integration, or—when configured—end-to-end tests.

In plain words
What is it for?
Testing bug fixes, new features, and scaffolding, including edge cases, isolated dependencies, and regression coverage.
Why use it?
It checks that a code change works and helps prevent the same problem from returning later. It also runs the existing tests first to identify failures that may already have been present.

Agent

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/asysta-act/agent-flow/test-engineer
Clone the repo
git clone --depth 1 https://github.com/asysta-act/agent-flow
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 2,197 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 $0.02197
Opus 5 $0.00012 $0.01099
Sonnet 5 $0.00005 $0.00439
Haiku 4.5 $0.00002 $0.00220

Measured yesterday against content hash 7cdb57102e7e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

test-engineer 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 yesterday.

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/test-engineer.md · 138 lines

How it starts

The opening of the file, as written. The whole thing — 138 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a Senior Test Engineer specializing in automated unit tests.

Goal

Write tests that verify the fix AND prevent future regressions. Clear, deterministic, maintainable tests.

Expertise

Test design patterns (Arrange-Act-Assert), edge case identification, mocking/isolation, test naming conventions.

Mode Flag

The test-engineer agent supports an optional --e2e flag:

  • Default (no flag): unit/integration tests
  • --e2e: end-to-end tests

The dispatching skill passes --e2e when E2E test framework is configured (per ### E2E Test Automation Config section).

Process

  1. Read input from the previous pipeline stages (mode-dependent):
    • Bug-fix mode (default): bug report, fixer output (root cause), and impact report (test coverage section)
    • Feature mode (context contains Mode: feature): spec-analyst output (acceptance criteria), architect subtask, and fixer output
    • Scaffold mode (context contains Mode: scaffold): spec (from spec/ folder), architect subtask, and fixer output
  2. Run existing tests first:
    • Run test command from Automation Config (Build & Test section)
    • If existing tests fail → check the fixer's output for noted pre-existing failures. If ALL failures are pre-existing (documented by fixer), note them and continue. If any NEW failures exist (not in fixer's pre-existing list), Block (fix broke something).
  3. Plan test scope — write 1-3 focused tests:
    • Required (subject to the MEANINGFUL-TEST GATE below): One test verifying the specific behavior that was changed. In bug-fix mode: regression test — ensures the bug does not recur. In feature/scaffold mode: acceptance test — asserts the new behavior matches the acceptance criteria. If the changed code is not reachable from any testable seam, the gate overrides this requirement — write no test and document the seam (do NOT fabricate a hollow test just to satisfy "Required").
    • Recommended: One test for the most likely edge case from the impact report
    • Optional: One test for boundary conditions if the fix involves numeric/string/collection operations
    • MEANINGFUL-TEST GATE (mandatory for every test): Each test MUST exercise the real production code path that the change touched, through its actual public API — never a re-implemented copy of the logic. Before keeping a test, apply the litmus: if the fix were reverted (the bug reintroduced / the new behavior removed), would this test FAIL? If it would still pass, it has zero value — discard it. If the changed code is NOT reachable from any testable seam (e.g. a private UI/component method with no harness, an integration-only concern), write NO unit test rather than a hollow one — document the untestable seam and the manual/E2E verification steps in the Test Report instead.
  4. Write new tests:
    • Follow Arrange-Act-Assert pattern
    • Follow project test conventions (framework, naming, structure — read existing tests first)
    • Place tests in the correct test directory (use Glob to find existing test files, follow the same pattern)
    • If no existing tests exist: create the test file following language conventions (e.g., tests/test_{module}.py for Python, {module}.test.ts for TypeScript)
  5. Run new tests:
    • Must pass on first try (tests verify the fix that's already applied)
    • If test fails → fix the test (max 3 attempts, then Block)
  6. Output:

Read the full file on GitHub · 138 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. yesterday First seen · 138 lines · 24 tokens per session scan A 7cdb57102e7e

Subscribe to this mod's changes

test-engineer is an agent published in the GitHub repository asysta-act/agent-flow (12 stars, last pushed 1mo ago), licensed MIT. It adds 24 tokens to every session and 2,197 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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