Automated summary
This skill guides the design of realistic mock API services for development, testing, and demos by simulating how a real API behaves.
Strengths
- Defines routes, scenarios, and state transitions before generating responses
- Recommends deterministic fixtures with optional randomness toggles
- Documents how to run the mock server and switch scenarios
- Includes clear safeguards against reusing production secrets or real customer data
Limitations
- Assumes an existing API contract or expected behavior to mock
- Does not cover security testing, penetration testing, or live production integrations
- Relies on an external playbook file for concrete code samples
Use it when you need to build a mock API for frontend work, integration testing, a simulated partner API, or a demo environment.
Avoid it for testing real production systems or live integrations, or when no API contract or expected behavior is available.
Security analysis
SafeThe skill contains only benign API-mocking guidance and safety notes. It declares no allowed tools and does not instruct destructive actions, secret exfiltration, obfuscated payloads, or safety disabling.
No concerns found
How this analysis is madeExamples
Create a mock of our payments partner API with routes for charge creation, refunds, and a configurable 500-error scenario so the frontend team can work in parallel with the backend.Our mock server returns happy-path responses only. Add scenario switching so we can simulate auth failures, rate limits, and slow responses, and document how to toggle each one.Build a mock API from this OpenAPI spec with deterministic fixtures and an optional randomness toggle, so we can validate our client against the contract before the backend is ready.name: api-testing-observability-api-mock description: "You are an API mocking expert specializing in realistic mock services for development, testing, and demos. Design mocks that simulate real API behavior and enable parallel development." risk: unknown source: community date_added: "2026-02-27"
API Mocking Framework
You are an API mocking expert specializing in creating realistic mock services for development, testing, and demonstration purposes. Design comprehensive mocking solutions that simulate real API behavior, enable parallel development, and facilitate thorough testing.
Use this skill when
- Building mock APIs for frontend or integration testing
- Simulating partner or third-party APIs during development
- Creating demo environments with realistic responses
- Validating API contracts before backend completion
Do not use this skill when
- You need to test production systems or live integrations
- The task is security testing or penetration testing
- There is no API contract or expected behavior to mock
Safety
- Avoid reusing production secrets or real customer data in mocks.
- Make mock endpoints clearly labeled to prevent accidental use.
Context
The user needs to create mock APIs for development, testing, or demonstration purposes. Focus on creating flexible, realistic mocks that accurately simulate production API behavior while enabling efficient development workflows.
Requirements
$ARGUMENTS
Instructions
- Clarify the API contract, auth flows, error shapes, and latency expectations.
- Define mock routes, scenarios, and state transitions before generating responses.
- Provide deterministic fixtures with optional randomness toggles.
- Document how to run the mock server and how to switch scenarios.
- If detailed implementation is requested, open
resources/implementation-playbook.md.
Resources
resources/implementation-playbook.mdfor code samples, checklists, and templates.
From the file to a first result
The download contains exactly the content displayed on this page. This copy may differ from the latest version in the source repository.
View the source and supporting filesThis download contains SKILL.md only. Any scripts, references, templates and dependencies are not included. Get the required files from the source, preserving their directory structure, before continuing.
1. Download the file
Download SKILL.mdFrom the root of a test project, save the file as .skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md, or use the command below. This folder is for inspecting the skill before installation.
Command for macOS/Linux or WSL: requires a POSIX shell and curl. On Windows without WSL, use the download button and create the folder manually.
mkdir -p '.skill-downloads/api-mocking-for-testing-development-msh3ushj' && curl --fail --show-error --location 'https://skills-guides.com/api/skills/api-mocking-for-testing-development-msh3ushj/download' --output '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md.part' && mv '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md.part' '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md'2. Check prerequisites
Read SKILL.md before using it. If it references scripts or external services, inspect them and prepare the required access in your test environment.
Original excerpt: Requirements
$ARGUMENTS
The platforms on this page are catalog indications. The paths below follow tool documentation; they do not prove this skill has been run in those tools. No minimum tool version is confirmed for this listing.
3. Load the skill
After inspection, copy the complete folder into your project using one of the commands below, then open a new tool session. The command stops if a folder with the same name already exists: compare the files before replacing it.
Claude Code
test -f '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md' && test -s '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md' && mkdir -p '.claude/skills' && test ! -e '.claude/skills/api-testing-observability-api-mock' && cp -R '.skill-downloads/api-mocking-for-testing-development-msh3ushj' '.claude/skills/api-testing-observability-api-mock'Cursor
test -f '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md' && test -s '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md' && mkdir -p '.cursor/skills' && test ! -e '.cursor/skills/api-testing-observability-api-mock' && cp -R '.skill-downloads/api-mocking-for-testing-development-msh3ushj' '.cursor/skills/api-testing-observability-api-mock'Codex
test -f '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md' && test -s '.skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md' && mkdir -p '.agents/skills' && test ! -e '.agents/skills/api-testing-observability-api-mock' && cp -R '.skill-downloads/api-mocking-for-testing-development-msh3ushj' '.agents/skills/api-testing-observability-api-mock'OpenSkills
OpenSkills must already be installed. The local install/read procedure is checked with OpenSkills 1.5.0, which requires Node.js ≥ 20.6.0. Catalog slugs are not resolved automatically.
Official OpenSkills installationopenskills install './.skill-downloads/api-mocking-for-testing-development-msh3ushj'openskills read 'api-mocking-for-testing-development-msh3ushj'Reading should display the installed file content and its base directory. It does not run the skill or install its dependencies.
For an agent that reads AGENTS.md, then sync the index. This command changes AGENTS.md: review the diff before using it.
openskills syncManual method or another tool: attach SKILL.md to a conversation, or open it in an agent that can read files. Include any required supporting resources. No universal folder is recognized by every tool.
4. Try a first task
Use a short, synthetic input: an API endpoint, a small document or an interface brief. In a new conversation, attach the file or give the agent its path, then adapt this request:
Read .skill-downloads/api-mocking-for-testing-development-msh3ushj/SKILL.md and apply its instructions to this example: [describe a test input]. Identify any missing files, dependencies or access. Produce the result requested by the skill without inventing data or running unreviewed scripts.Expected result: output matching the skill instructions, or a precise list of missing prerequisites. A read confirmation alone does not validate a first use. If an external resource is unavailable, that path remains untested.
ClickHouse Performance Comparison
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Analyze CI Performance Reports
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Analyze CI performance comparison reports for a ClickHouse PR. Cross-references master history to distinguish real regressions from flaky tests.
Santa Method
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Multi-agent adversarial verification with two independent reviewers. Output is checked twice and iteratively fixed until both pass before shipping.