emulate

A local emulator that provides drop-in replacements for developer services such as GitHub, Slack, AWS, Stripe, and Linear. An emulator imitates a service on your own computer so software can interact with it locally.

In plain words
What is it for?
Use it to start local service environments, load seed data, write integration tests, and run CI in a network-restricted setup.
Why use it?
It lets developers test integrations and continuous-integration jobs without relying on live network services or making real external changes.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/pleaseai/claude-code-plugins/emulate
Any agent
npx skills add pleaseai/claude-code-plugins --skill emulate
Clone the repo
git clone --depth 1 https://github.com/pleaseai/claude-code-plugins

Made for: Claude Code, Codex.

Per session 115 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,422 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 98% copy Near-identical to another mod 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 $0.00115 $0.03422
Opus 5 $0.00057 $0.01711
Sonnet 5 $0.00023 $0.00684
Haiku 4.5 $0.00012 $0.00342

Measured yesterday against content hash 978f57fbf354, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

emulate 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 yesterday.

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.

Origin

This is a copy

98% identical to emulate — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/emulate/.agents/skills/emulate/SKILL.md · 412 lines

How it starts

The opening of the file, as written. The whole thing — 412 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Service Emulation with emulate

Local drop-in replacement services for CI and no-network sandboxes. Fully stateful, production-fidelity API emulation, not mocks.

Quick Start

npx emulate

All services start with sensible defaults:

Service Default Port
Vercel 4000
GitHub 4001
Google 4002
Slack 4003
Apple 4004
Microsoft 4005
Okta 4006
AWS 4007
Resend 4008
Stripe 4009
MongoDB Atlas 4010
Clerk 4011
Linear 4012
Twilio 4013

CLI

# Start all services (zero-config)
npx emulate

# Start specific services
npx emulate --service vercel,github

# Custom base port (auto-increments per service)
npx emulate --port 3000

# Use a seed config file
npx emulate --seed config.yaml

# Generate omitted service secrets into a private file
npx emulate start --seed config.yaml --generated-secrets-file .emulate-secrets.json

# Generate a starter config
npx emulate init

# Generate config for a specific service
npx emulate init --service vercel

# List available services
npx emulate list

Options

Flag Default Description
-p, --port 4000 Base port (auto-increments per service)
-s, --service all Comma-separated services to enable
--seed auto-detect Path to seed config (YAML or JSON)
--base-url none Override advertised base URL (supports {service} template)
--portless off Serve over HTTPS via portless (auto-registers aliases)
--generated-secrets-file none Generate omitted service secrets and write them to a new owner-only JSON file

The port can also be set via EMULATE_PORT or PORT environment variables.

The generated-secrets destination must not exist. emulate removes inherited ACLs, verifies effective owner-only access, and publishes complete JSON before opening listeners or configuring portless. Handled startup failures remove the invocation-owned artifact. A hard termination can leave a complete artifact that must be removed manually after confirming no invocation is using it. Only service-generated values appear in the artifact. Linux requires setfacl and getfacl from the acl package. The flag fails closed when access controls cannot be verified and is not supported on Windows.

Read the full file on GitHub · 412 lines

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. yesterday First seen · 412 lines · 115 tokens per session scan A 978f57fbf354

Subscribe to this mod's changes

emulate is a skill published in the GitHub repository pleaseai/claude-code-plugins (13 stars, last pushed 7d ago), licensed MIT. It adds 115 tokens to every session and 3,422 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to emulate, differing in 2 lines, and is treated as a copy.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens

babysit-pr

Babysit a GitHub pull request after creation by continuously polling review comments, CI checks/workflow runs, and mergeability state until the PR is merged/closed or user help is required. Diagnose failures, retry likely flaky failures up to 3 times, auto-fix/push branch-related issues when appropriate, and keep…

openai/codex · 114 tokens

imagegen

Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output…

openai/codex · 113 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

next-cache-components-optimizer

Drive a Next.js route to instant navigation by setting up an agentic loop, under Cache Components / PPR, on initial load (hard navigation) and client-side navigation (soft navigation). Encode the goal as a failing @next/playwright instant() e2e and work it to green, one verified route at a time; the shipped test then…

vercel/next.js · 170 tokens