API Test Suite Builder
borghei/Claude-Skills
Generate API test suites from route definitions across frameworks: auth, input validation, contract, k6 load testing, mocking, and OpenAPI-driven generation.
Add and evolve Counterfact context classes in .context.ts files, including required unit test coverage for context behavior.
Install Context
$ npx skills add counterfact/api-simulator --skill context -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install counterfact/api-simulator context --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/context .claude/skills/context && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "context" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/context into .claude/skills/context/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "context", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/counterfact/api-simulator/tree/main/skills/contextType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add counterfact/api-simulator --skill context -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install counterfact/api-simulator context --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/context .agents/skills/context && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "context" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/context into .agents/skills/context/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "context", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add counterfact/api-simulator --skill context -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install counterfact/api-simulator context --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/context .cursor/skills/context && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "context" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/context into .cursor/skills/context/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "context", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/counterfact/api-simulator.git --path skills/context--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add counterfact/api-simulator --skill context -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install counterfact/api-simulator context --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/context .gemini/skills/context && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "context" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/context into .gemini/skills/context/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "context", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install counterfact/api-simulator contextInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add counterfact/api-simulator --skill context -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/context .github/skills/context && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "context" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/context into .github/skills/context/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "context", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add counterfact/api-simulator --skill context -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install counterfact/api-simulator context --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/context .opencode/skills/context && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "context" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/context into .opencode/skills/context/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "context", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
context- GitHub stars
- 170
- Token cost
- ~384 tokens
- SKILL.md length
- 160 words
- Files
- 1
- Skills in repo
- 12
- Repo updated
- First seen
- Licence
- MIT
At a glance
Add and evolve Counterfact context classes in .context.ts files, including required unit test coverage for context behavior.
- Works in 4 steps: Update or add methods in… → Keep route files calling these methods… → Add/adjust unit tests for the changed… → …
- Tasks that involve Unit testing
- SKILL.md covers Purpose, What _.context.ts is for, Context class API expectations and Required rules, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Context is an agent skill from counterfact/api-simulator. Add and evolve Counterfact context classes in .context.ts files, including required unit test coverage for context behavior.
Its SKILL.md is about 380 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Testing & QA, covering Unit testing and OpenAPI specifications. It works with OpenAPI. The repository describes itself as: Turn an OpenAPI spec into a local API in one command. Build and test your frontend with custom responses, shared state, and simulated failures, without waiting for the backend. The licence is MIT.
When your agent uses it
- Tasks that involve Unit testing
- Tasks that involve OpenAPI specifications
Example prompts
- “/context”
Workflow steps
4 steps, taken from the first numbered list in SKILL.md.
- Update or add methods in routes/**/_.context.ts.
- Keep route files calling these methods via $.context.
- Add/adjust unit tests for the changed context methods.
- If sample data is needed, add/update a scenario function instead of hardcoding
What it can do on your machine
Read from SKILL.md and the folder at commit 403e3e5. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
counterfact.dev
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Context loads about 384 tokens when it runs. Until then it costs about 33 tokens; SKILL.md has 160 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from counterfact/api-simulator at commit 403e3e5, republished under its MIT licence (© counterfact). 160 words, ~384 tokens.
Download SKILL.mdSave it as
.claude/skills/context/SKILL.md (or your agent's skills folder).- name
- context
- description
- Add and evolve Counterfact context classes in _.context.ts files, including required unit test coverage for context behavior.
- applyTo
- **/_.context.{ts,js}, **/routes/**/_.context.ts, **/*context.{ts,js}, packages/counterfact/test/**/*.test.ts
Context Skill
Purpose
Define and maintain stateful business logic in _.context.ts files.
What _.context.ts is for
A _.context.ts file owns state and business rules for a route subtree.
Handlers call methods on $.context; they should not implement core logic
inline.
Context class API expectations
- Expose methods for domain actions (create/read/update/delete/query).
- Keep state private where possible.
- Return plain values that route handlers can map to HTTP responses.
- Use clear method names that describe behavior (not transport concerns).
Required rules
- Any new or modified context method must include unit tests.
- Test the Context class directly (no server boot required).
- Do not populate dummy data directly in context changes.
- Delegate dummy data creation/seeding to scenario modules under
scenarios/.
Step-by-step
- Update or add methods in
routes/**/_.context.ts. - Keep route files calling these methods via
$.context. - Add/adjust unit tests for the changed context methods.
- If sample data is needed, add/update a scenario function instead of hardcoding defaults in context constructors.
References
© counterfact, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in skills/context of counterfact/api-simulator.
Open the folder on GitHubat commit 403e3e5
Compare with similar skills
Context next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Context this skillcounterfact/api-simulator | 170 | — | ~384 | Automated safety check: Pass | MIT | |
| API Test Suite Builderborghei/Claude-Skills | 874 | — | ~1.6k | Automated safety check: Pass | MIT | |
| NestJS ExpertJeffallan/claude-skills | 12k | — | ~2k | Automated safety check: Pass | MIT | |
| Cloud Agents Starterscalar/scalar | 16k | — | ~1.4k | Automated safety check: Pass | MIT | |
| 703 Technologies Fuzzing Testingjabrena/plinth | 445 | — | ~874 | Automated safety check: Pass | Apache-2.0 | |
| Contract Testingpetrkindlmann/qa-skills | 163 | — | ~4.1k | Automated safety check: Pass | MIT |
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Related
Works with
Categories
Questions about Context
What does Context do?
Add and evolve Counterfact context classes in .context.ts files, including required unit test coverage for context behavior. Context is an agent skill from counterfact/api-simulator.ts files, including required unit test coverage for context behavior.
When should I use Context?
Context fits situations like: tasks that involve Unit testing; tasks that involve OpenAPI specifications.
How do I install Context in Claude Code?
Run `npx skills add counterfact/api-simulator --skill context -a claude-code`. Or copy the skill folder (skills/context in counterfact/api-simulator) into .claude/skills/context in your project. Claude Code loads it when a task matches its description.
How do I install Context in Codex?
Run `npx skills add counterfact/api-simulator --skill context -a codex`. Or copy the skill folder (skills/context in counterfact/api-simulator) into .agents/skills/context in your project. Codex loads it when a task matches its description.
Can I use Context in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add counterfact/api-simulator --skill context -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/context, .gemini/skills/context, .github/skills/context and .opencode/skills/context in your project.
What does Context need to run?
SKILL.md names no scripts, command-line tools or credentials: Context is instructions for the agent only.
Does Context access the network?
SKILL.md names 1 domain. As links in the text: counterfact.dev. This is read from the text; nothing was executed.
Is Context safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Context use?
Context is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Context use?
About 384 tokens (SKILL.md is roughly 1.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Context?
Skills that share tags, products or a category with Context: API Test Suite Builder (borghei/Claude-Skills, 874 stars), NestJS Expert (Jeffallan/claude-skills, 12k stars), Cloud Agents Starter (scalar/scalar, 16k stars) and 703 Technologies Fuzzing Testing (jabrena/plinth, 445 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Context?
counterfact (a GitHub organization) maintains it in counterfact/api-simulator, which has 170 GitHub stars. The repository holds 12 skills in this directory. The repository was last updated on October 6, 2026.
Source: counterfact/api-simulator on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.