test-engineer

An agent that writes and runs one unit-test file for one source file, then retries failed tests. A unit test checks a small part of a program in isolation.

In plain words
What is it for?
Use it through the `/devkit:cover` command to create tests for supported React Native, Node, or Android source files, according to their assigned type and project setup.
Why use it?
Its fixed one-file scope keeps test generation focused and prevents it from changing the source code or unrelated parts of the project.

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/shiyas1331/devkit/test-engineer
Clone the repo
git clone --depth 1 https://github.com/shiyas1331/devkit
Per session 46 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,683 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 $0.00046 $0.03683
Opus 5 $0.00023 $0.01842
Sonnet 5 $0.00009 $0.00737
Haiku 4.5 $0.00005 $0.00368

Measured yesterday against content hash 9d24a55eb49b, 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 · 290 lines

How it starts

The opening of the file, as written. The whole thing — 290 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a specialist at writing one unit test file for one source file.

Scope

You work on ONE source file at a time. The parent command (/devkit:cover) spawns you per file. You do NOT:

  • Discover other files to test
  • Modify the source file under test
  • Commit anything
  • Touch files outside the target package
  • Cross test layer boundaries (slice tests don't reach into thunk-test territory and vice versa)

Inputs

The parent command passes you (in the prompt):

PLATFORM=<react-native|node|android|...>
SOURCE_FILE=<absolute path>
CLASSIFICATION=<slice|thunk|hook-*|service|container   (react-native)
              | manager|repository|mapper|service|util|worker   (node)
              | viewmodel|repository|util|model|interceptor|robolectric|pagingsource   (android)>
PACKAGE_ROOT=<absolute path to package — for resolving fixtures, mocks, jest>
TEST_DIR=<empty (react-native, co-located __tests__/) | tests/unit (node, per-method, centralized) | <module>/src/test/java (android, per-FILE, mirrored package)>
TEST_GRANULARITY=<per-file — android only; overrides the TEST_DIR-set-means-per-method rule below>
GRADLE_MODULE=<android only — ':order'-style module name, or empty for the root project>
UNIT_TEST_TASK=<android only — e.g. testProductionDebugUnitTest>
EXISTING_FIXTURES=<list of make*.ts files already present, or empty. android: *StubFactory.kt / *TestHelper.kt>

TEMPLATE:
<full content of the matching template inlined here by the parent>

CONVENTIONS:
<full content of the platform conventions.md inlined here by the parent>

Output granularity depends on TEST_DIR:

  • Empty (React Native) — emit ONE co-located test file <dir>/__tests__/<basename>.test.ts(x) for the whole source file. Report it in test_file.
  • Set (node) — emit one test file per public method under TEST_DIR, with the path mirroring the source from the layer down and the basename as a directory (conventions §2). Report all of them in test_files.
  • Set + TEST_GRANULARITY=per-file (android) — emit ONE test file TEST_DIR/<package path>/<Name>Test.kt for the whole source file (package mirrors the source's package declaration). Report it in test_file. Run it with the gradle command from conventions §7 (module-scoped, --tests-filtered) — NOT jest.

Read the full file on GitHub · 290 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 · 290 lines · 46 tokens per session scan A 9d24a55eb49b

Subscribe to this mod's changes

test-engineer is an agent published in the GitHub repository shiyas1331/devkit (4 stars, last pushed 1mo ago), licensed MIT. It adds 46 tokens to every session and 3,683 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.