ToolJet Marketplace Plugin Builder
ToolJet/ToolJet
Turns an API description, such as an OpenAPI file or a Postman collection, into a connector plugin for ToolJet's marketplace and checks it with the repo's validator.
Create and update Counterfact scenario modules that seed or mutate context state through reusable scenario functions.
Install Scenario
$ npx skills add counterfact/api-simulator --skill scenario -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install counterfact/api-simulator scenario --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/scenario .claude/skills/scenario && 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 "scenario" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/scenario into .claude/skills/scenario/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "scenario", 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/scenarioType 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 scenario -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install counterfact/api-simulator scenario --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/scenario .agents/skills/scenario && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "scenario" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/scenario into .agents/skills/scenario/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "scenario", 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 scenario -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install counterfact/api-simulator scenario --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/scenario .cursor/skills/scenario && 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 "scenario" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/scenario into .cursor/skills/scenario/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "scenario", 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/scenario--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 scenario -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install counterfact/api-simulator scenario --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/scenario .gemini/skills/scenario && 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 "scenario" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/scenario into .gemini/skills/scenario/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "scenario", 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 scenarioInstalls 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 scenario -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/scenario .github/skills/scenario && 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 "scenario" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/scenario into .github/skills/scenario/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "scenario", 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 scenario -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 scenario --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/scenario .opencode/skills/scenario && 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 "scenario" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/scenario into .opencode/skills/scenario/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "scenario", 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
scenario- GitHub stars
- 170
- Token cost
- ~356 tokens
- SKILL.md length
- 115 words
- Files
- 1
- Skills in repo
- 12
- Repo updated
- First seen
- Licence
- MIT
At a glance
Create and update Counterfact scenario modules that seed or mutate context state through reusable scenario functions.
- Tasks that involve OpenAPI specifications
- SKILL.md covers Purpose, Where scenario files live, Scenario function API and Required rules, plus 1 more section
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Scenario is an agent skill from counterfact/api-simulator. Create and update Counterfact scenario modules that seed or mutate context state through reusable scenario functions.
Its SKILL.md is about 360 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 Backend & APIs, covering 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 OpenAPI specifications
Example prompts
- “/scenario”
What it can do on your machine
Read from SKILL.md and the folder at commit ad1a2a3. 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 (its code samples are typescript).
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
Scenario loads about 356 tokens when it runs. Until then it costs about 32 tokens; SKILL.md has 115 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 ad1a2a3, republished under its MIT licence (© counterfact). 115 words, ~356 tokens.
Download SKILL.mdSave it as
.claude/skills/scenario/SKILL.md (or your agent's skills folder).- name
- scenario
- description
- Create and update Counterfact scenario modules that seed or mutate context state through reusable scenario functions.
- applyTo
- **/scenarios/**/*.{ts,js}
Scenario Skill
Purpose
Create scenario files that seed and manipulate runtime data for Counterfact mocks.
Where scenario files live
- Put scenario modules in
scenarios/. - Keep
scenarios/index.tsas the primary export surface. - Use
startupinscenarios/index.tsfor automatic boot-time seeding.
Scenario function API
A scenario is a function receiving $ and using it to access context and route
helpers.
// Path is relative to the scenarios directory at the generated project root.
import type { Scenario } from "../types/_.context.js";
export const startup: Scenario = ($) => {
$.context.createThing({ name: "example" });
};Typical $ usage in scenarios:
$.contextfor state changes$.route("/path")for calling routes from scenario setup flows
Required rules
- Keep reusable business operations in contexts; scenarios orchestrate calls.
- Keep scenarios focused on setup flows and fixtures.
- Do not create unit tests in this skill; scenario behavior should be checked through end-to-end route behavior and manual/acceptance flows.
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/scenario of counterfact/api-simulator.
Open the folder on GitHubat commit ad1a2a3
Compare with similar skills
Scenario 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 |
|---|---|---|---|---|---|---|
| Scenario this skillcounterfact/api-simulator | 170 | — | ~356 | Automated safety check: Pass | MIT | |
| ToolJet Marketplace Plugin BuilderToolJet/ToolJet | 41k | — | ~2.1k | Automated safety check: Pass | AGPL-3.0 | |
| Step Partsearthtojake/text-to-cad | 18k | 1 repos | ~1.5k | Automated safety check: Pass | MIT | |
| API DesignerJeffallan/claude-skills | 12k | 2 repos | ~2k | Automated safety check: Pass | MIT | |
| OpenAPI to MCP Servermcp-use/mcp-use | 11k | — | ~5.2k | Automated safety check: Pass | Apache-2.0 | |
| Use Yaakmountain-loop/yaak | 19k | — | ~1.9k | Automated safety check: Pass | MIT |
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More from counterfact/api-simulator
All 12 skills in this repoCounterfact PR Creation
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Create Counterfact pull requests with the required agent-authored acceptance and repository-learning notes; do not use to review another PR.
Counterfact Repl
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Interact with Counterfact mock API server programmatically. An agent skill from counterfact/api-simulator.
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Keep contributor changes aligned with repository test patterns, diagnostics, black-box test boundaries, release/versioning workflow, documentation requirements, and compatibility.
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Route
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Related
Works with
Categories
Questions about Scenario
What does Scenario do?
Create and update Counterfact scenario modules that seed or mutate context state through reusable scenario functions. Scenario is an agent skill from counterfact/api-simulator. Create and update Counterfact scenario modules that seed or mutate context state through reusable scenario functions.
When should I use Scenario?
Scenario fits situations like: tasks that involve OpenAPI specifications.
How do I install Scenario in Claude Code?
Run `npx skills add counterfact/api-simulator --skill scenario -a claude-code`. Or copy the skill folder (skills/scenario in counterfact/api-simulator) into .claude/skills/scenario in your project. Claude Code loads it when a task matches its description.
How do I install Scenario in Codex?
Run `npx skills add counterfact/api-simulator --skill scenario -a codex`. Or copy the skill folder (skills/scenario in counterfact/api-simulator) into .agents/skills/scenario in your project. Codex loads it when a task matches its description.
Can I use Scenario 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 scenario -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/scenario, .gemini/skills/scenario, .github/skills/scenario and .opencode/skills/scenario in your project.
What does Scenario need to run?
SKILL.md names no scripts, command-line tools or credentials: Scenario is instructions for the agent only.
Does Scenario 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 Scenario 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 Scenario use?
Scenario 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 Scenario use?
About 356 tokens (SKILL.md is roughly 1.4k 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 Scenario?
Skills that share tags, products or a category with Scenario: ToolJet Marketplace Plugin Builder (ToolJet/ToolJet, 41k stars), Step Parts (earthtojake/text-to-cad, 18k stars), API Designer (Jeffallan/claude-skills, 12k stars) and OpenAPI to MCP Server (mcp-use/mcp-use, 11k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Scenario?
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 8, 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.