test-writer

test-writer is a skill for Claude Code, Codex from vstorm-co/pydantic-deepagents. It costs 11 tokens per session (267 once invoked), scanned A, original, MIT.

A test-writing assistant that reads existing source code and creates tests using the project's testing framework and conventions.

In plain words
What is it for?
Use it to test public functions, boundary values, missing arguments, external-service failures, state changes, return values, and side effects.
Why use it?
It helps find untested normal, edge, invalid-input, failure, and multi-function behavior before those cases become bugs.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to test public functions, boundary values, missing arguments, external-service failures, state changes, return values, and side effects.

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Install with agentmods
npx agentmods add skills/vstorm-co/pydantic-deepagents/test-writer
About the project

Pydantic Deep Agents is a self-hosted terminal AI assistant and Python framework for building coding, research, and other AI agents. It gives agents tools such as file access, shell commands, planning, memory, sub-agents, sandboxed execution, and MCP connections, and supports different models.

vstorm-co/pydantic-deepagents · 1,059 stars · on GitHub · vstorm-co.github.io

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.

Any agent
npx skills add vstorm-co/pydantic-deepagents --skill test-writer
Clone the repo
git clone --depth 1 https://github.com/vstorm-co/pydantic-deepagents

Made for: Claude Code, Codex.

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 test-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/vstorm-co/pydantic-deepagents/test-writer/github.svg)](https://agentmods.dev/skills/vstorm-co/pydantic-deepagents/test-writer)
Your own site
<a href="https://agentmods.dev/skills/vstorm-co/pydantic-deepagents/test-writer"><img src="https://agentmods.dev/badge/skills/vstorm-co/pydantic-deepagents/test-writer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for test-writer

Your own site · 80×15
<a href="https://agentmods.dev/skills/vstorm-co/pydantic-deepagents/test-writer"><img src="https://agentmods.dev/badge/skills/vstorm-co/pydantic-deepagents/test-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 11 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 267 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00011 $0.00267
Opus 5 $0.00005 $0.00133
Sonnet 5 $0.00002 $0.00053
Haiku 4.5 $0.00001 $0.00027

Measured 10d ago against content hash f5b6dde6b01d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

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 10d 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.

apps/cli/skills/test-writer/SKILL.md · 47 lines

What it actually says

Test Writer

Generate comprehensive tests for the target code.

Process

  1. Read the source code to understand all public functions/methods
  2. Identify the testing framework already used in the project (pytest, unittest, etc.)
  3. Follow existing test patterns and conventions in the project
  4. Write tests covering all categories below

Coverage Strategy

Happy Path

  • Normal inputs with expected outputs
  • All public methods/functions

Edge Cases

  • Empty inputs (empty string, empty list, None)
  • Boundary values (0, -1, max int)
  • Single element collections

Error Cases

  • Invalid input types
  • Missing required arguments
  • Network/IO failures (mock external calls)

Integration

  • Multiple functions working together
  • State changes across calls

Guidelines

  • One test function per behavior, not per method
  • Descriptive test names: test_<what>_<condition>_<expected>
  • Use fixtures for shared setup
  • Mock external dependencies (APIs, databases, filesystem)
  • Assert specific values, not just truthiness
  • Test both return values and side effects
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. 10d ago First seen · 47 lines · 11 tokens per session scan A f5b6dde6b01d

Subscribe to this mod's changes

test-writer is a skill published in the GitHub repository vstorm-co/pydantic-deepagents (1,059 stars, last pushed 18d ago), licensed MIT. It adds 11 tokens to every session and 267 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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