Agent skill

Route

by counterfact in counterfact/api-simulator

Edit Counterfact route files to add endpoint behavior while keeping handlers thin and delegating business logic to context classes.

MITAuto-check passedBackend & APIs

Install Route

skills CLI

$ npx skills add counterfact/api-simulator --skill route -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install counterfact/api-simulator route --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/route .claude/skills/route && rm -rf skills-src

Use ~/.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/

Paste into Claude Code

Install the "route" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/route into .claude/skills/route/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "route", 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

$skill-installer install https://github.com/counterfact/api-simulator/tree/main/skills/route

Type 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.

skills CLI

$ npx skills add counterfact/api-simulator --skill route -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install counterfact/api-simulator route --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/route .agents/skills/route && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "route" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/route into .agents/skills/route/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "route", 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.

skills CLI

$ npx skills add counterfact/api-simulator --skill route -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install counterfact/api-simulator route --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/route .cursor/skills/route && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "route" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/route into .cursor/skills/route/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "route", 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

$ gemini skills install https://github.com/counterfact/api-simulator.git --path skills/route

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add counterfact/api-simulator --skill route -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install counterfact/api-simulator route --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/route .gemini/skills/route && rm -rf skills-src

Use ~/.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/

Paste into Gemini CLI

Install the "route" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/route into .gemini/skills/route/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "route", 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.

GitHub CLI

$ gh skill install counterfact/api-simulator route

Installs 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).

skills CLI

$ npx skills add counterfact/api-simulator --skill route -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/route .github/skills/route && rm -rf skills-src

Use ~/.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/

Paste into GitHub Copilot

Install the "route" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/route into .github/skills/route/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "route", 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.

skills CLI

$ npx skills add counterfact/api-simulator --skill route -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install counterfact/api-simulator route --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/counterfact/api-simulator.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/route .opencode/skills/route && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "route" agent skill from https://github.com/counterfact/api-simulator/tree/main/skills/route into .opencode/skills/route/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "route", 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: route
GitHub stars: 170
Token cost: ~341 tokens
SKILL.md length: 123 words
Files: 1
Skills in repo: 12
Repo updated: Oct 8, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Edit Counterfact route files to add endpoint behavior while keeping handlers thin and delegating business logic to context classes.

Works in 5 steps: Open the target file under routes/ (e.g.… → Read input using $ ($.path, $.query,… → Call a context method for logic/state… → …
Tasks that involve OpenAPI specifications
SKILL.md covers Purpose, Required rules, Step-by-step and Pattern, plus 1 more section
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Route is an agent skill from counterfact/api-simulator. Edit Counterfact route files to add endpoint behavior while keeping handlers thin and delegating business logic to context classes.

Its SKILL.md is about 340 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

“/route”

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

Open the target file under routes/ (e.g. routes/pet/{petId}.ts).
Read input using $ ($.path, $.query, $.body).
Call a context method for logic/state changes.
Return a response using $.response[status].
If needed, add new context methods instead of embedding logic in the route.

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

Route loads about 341 tokens when it runs. Until then it costs about 34 tokens; SKILL.md has 123 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~34
When it runs · the whole SKILL.md, loaded when a task matches: ~341

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). 123 words, ~341 tokens.

Download SKILL.mdSave it as .claude/skills/route/SKILL.md (or your agent's skills folder).

name: route
description: Edit Counterfact route files to add endpoint behavior while keeping handlers thin and delegating business logic to context classes.
applyTo: **/routes/**/*.{ts,js}

Route Skill

Purpose

Implement or update route behavior in generated route files.

Required rules

Use the $ API in every handler ($.path, $.query, $.body, $.response, $.context, $.loadContext).
Route handlers must stay thin.
Business logic must be delegated to a context class in an appropriate _.context.ts file.
Do not create unit tests in this skill; routes are HTTP adapters and behavior should be validated through context tests and black-box/integration flows when available.

Step-by-step

Open the target file under routes/ (e.g. routes/pet/{petId}.ts).
Read input using $ ($.path, $.query, $.body).
Call a context method for logic/state changes.
Return a response using $.response[status].
If needed, add new context methods instead of embedding logic in the route.

Pattern

export const POST: HTTP_POST = ($) => {
  const created = $.context.createThing($.body);
  return $.response[201].json(created);
};

References

https://counterfact.dev/docs/features/state.html
packages/counterfact/src/server/dispatcher.ts for runtime handler behavior

Files

Just SKILL.md in skills/route of counterfact/api-simulator.

Open the folder on GitHubat commit ad1a2a3

Compare with similar skills

Route 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.

Route compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Route this skillcounterfact/api-simulator	170	—	~341	Automated safety check: Pass	MIT	today
ToolJet Marketplace Plugin BuilderToolJet/ToolJet	41k	—	~2.1k	Automated safety check: Pass	AGPL-3.0	today
Step Partsearthtojake/text-to-cad	18k	1 repos	~1.5k	Automated safety check: Pass	MIT	today
API DesignerJeffallan/claude-skills	12k	2 repos	~2k	Automated safety check: Pass	MIT	5 days ago
OpenAPI to MCP Servermcp-use/mcp-use	11k	—	~5.2k	Automated safety check: Pass	Apache-2.0	today
Use Yaakmountain-loop/yaak	19k	—	~1.9k	Automated safety check: Pass	MIT	yesterday

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Questions about Route

What does Route do?

Edit Counterfact route files to add endpoint behavior while keeping handlers thin and delegating business logic to context classes. Route is an agent skill from counterfact/api-simulator. Edit Counterfact route files to add endpoint behavior while keeping handlers thin and delegating business logic to context classes.

When should I use Route?

Route fits situations like: tasks that involve OpenAPI specifications.

How do I install Route in Claude Code?

Run `npx skills add counterfact/api-simulator --skill route -a claude-code`. Or copy the skill folder (skills/route in counterfact/api-simulator) into .claude/skills/route in your project. Claude Code loads it when a task matches its description.

How do I install Route in Codex?

Run `npx skills add counterfact/api-simulator --skill route -a codex`. Or copy the skill folder (skills/route in counterfact/api-simulator) into .agents/skills/route in your project. Codex loads it when a task matches its description.

Can I use Route 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 route -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/route, .gemini/skills/route, .github/skills/route and .opencode/skills/route in your project.

What does Route need to run?

SKILL.md names no scripts, command-line tools or credentials: Route is instructions for the agent only.

Does Route 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 Route 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 Route use?

Route 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 Route use?

About 341 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 Route?

Skills that share tags, products or a category with Route: 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 Route?

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.

Route

Install Route

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Route Skill

Purpose

Required rules

Step-by-step

Pattern

References

Files

Compare with similar skills

Similar skills

ToolJet Marketplace Plugin Builder

Step Parts

API Designer

OpenAPI to MCP Server

Use Yaak

Old Coder API Design

More from counterfact/api-simulator

Counterfact PR Creation

Counterfact Repl

Build Simulation

Counterfact Maintenance

Counterfact Repo Basics

Scenario

Questions about Route

Install Route

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Route Skill

Purpose

Required rules

Step-by-step

Pattern

References

Files

Compare with similar skills

Similar skills

More from counterfact/api-simulator

Related

Questions about Route