Enables feature flag management with percentage rollouts and A/B testing for Next.js applications.
Also known as sathergate/sathergate-toolkit
- Stars
- 106
- Tools
- —
- Downloads, 30 days
- —
- Latest version
- 0.1.1
- Last commit
- Sep 11, 2026
- License
- —
What is flagpost MCP?
flagpost enables feature flag management with percentage rollouts and A/B testing for Next.js applications.
Summary generated from the project's README
About flagpost MCP server
Flagpost provides feature flag management specifically designed for Next.js applications. It allows developers to implement percentage rollouts and A/B testing directly within their code. This package is part of the sathergate-toolkit, which focuses on agent-native infrastructure. Because it is built with the Model Context Protocol, AI coding agents can discover and interact with these tools directly.
Users implement the functionality by installing the package via npm and using the createFlagpost function. The system operates without requiring external services, relying on pure TypeScript to manage flag rules and default values. This local-first approach ensures that feature toggles and rollout percentages remain within the application environment. It is built with zero npm dependencies to maintain a lightweight footprint for developers.
What you can do with it
- 1Implement percentage rolloutsConfigure a new feature to be visible to only a specific portion of your users.
- 2Manage feature flagsSet up default values and rules for different application features.
- 3Enable agent-driven developmentAllow AI coding agents to automatically discover and use feature management tools.
Written from the project's README. Every use case is checked against a quote from it.
How to install flagpost MCP
Formats verified 10 Nov 2026Add to CursorAdd to GooseInstall flagpost MCP in Claude Code
$ claude mcp add flagpost -- npx -y flagpostInstall flagpost MCP in Cursor
~/.cursor/mcp.json
{
"mcpServers": {
"flagpost": {
"command": "npx",
"args": [
"-y",
"flagpost"
]
}
}
}Install flagpost MCP in VS Code
.vscode/mcp.json
{
"servers": {
"flagpost": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"flagpost"
]
}
}
}Install flagpost MCP in VS Code CLI
$ code --add-mcp '{"name":"flagpost","type":"stdio","command":"npx","args":["-y","flagpost"]}'Install flagpost MCP in Claude Desktop
claude_desktop_config.json
{
"mcpServers": {
"flagpost": {
"command": "npx",
"args": [
"-y",
"flagpost"
]
}
}
}Install flagpost MCP in Codex
$ codex mcp add flagpost -- npx -y flagpostInstall flagpost MCP in Codex config.toml
~/.codex/config.toml
[mcp_servers.flagpost] command = "npx" args = ["-y", "flagpost"]
Install flagpost MCP in Gemini CLI
$ gemini mcp add -s user flagpost npx -- -y flagpostInstall flagpost MCP in Gemini settings.json
~/.gemini/settings.json
{
"mcpServers": {
"flagpost": {
"command": "npx",
"args": [
"-y",
"flagpost"
]
}
}
}Automated checks
Ran Nov 14, 2026Full report →Passed our automated checks. That is not a security audit: read the code and give the server the narrowest access it needs. How checks work · What to fix for more points
- Source repository linked and reachablesathergate/sathergate-toolkit is public and reachablegithub.com/sathergate/sathergate-toolkit ↗Pass
- Package names this repository as its sourceflagpost names git+https://github.com/sathergate/flagpost.git as its sourcenpmjs.com/package/flagpost ↗Finding
- Build provenance (Sigstore attestation)No build attestation published for this releaseNot checked
- Open source license (OSI)No licenseFinding
- Commit or release in the last yearLast commit or release 2026-09-11github.com/sathergate/sathergate-toolkit ↗Pass
- OpenSSF ScorecardNot checked
- Package name not close to a popular packageNo popular package one edit away from flagpostPass
- No critical advisory in the package or its dependencies1 resolved dependencies checked; no critical advisoryosv.dev ↗Pass
- No hidden instructions to the model0 tool descriptions and the README read; no override phrases, credential paths or hidden charactersPass
- Destructive tools are labelledNot checked
- Remote endpoint answers the MCP handshakeNot checked
README
View on GitHubsathergate-toolkit
Agent-native infrastructure toolkit for Next.js. 8 packages, zero dependencies, MCP in every one.
Packages
| Package | Description | Install |
|---|---|---|
| gatehouse | Drop-in RBAC with role hierarchy | npm i gatehouse |
| shutterbox | Image processing pipeline | npm i shutterbox |
| flagpost | Feature flags with percentage rollouts | npm i flagpost |
| ratelimit-next | Rate limiting (sliding window, token bucket) | npm i ratelimit-next |
| notifykit | Unified notifications (email, SMS, push) | npm i @sathergate/notifykit |
| croncall | Serverless-native cron jobs | npm i croncall |
| vaultbox | AES-256-GCM encrypted secrets | npm i vaultbox |
| searchcraft | Full-text search with BM25 scoring | npm i searchcraft |
Or install them all:
npm i @sathergate/toolkit
Quick Start
import { createFloodgate } from "ratelimit-next";
import { createSifter } from "searchcraft";
import { createFlagpost } from "flagpost";
// Rate limiting
const limiter = createFloodgate({
rules: { api: { limit: 60, window: "1m" } },
});
// Full-text search
const search = createSifter({
schema: { title: { weight: 2 }, body: true },
documents: articles,
});
// Feature flags
const flags = createFlagpost({
flags: {
newSearch: { defaultValue: false, rules: [{ value: true, percentage: 25 }] },
},
});
See the kitchen-sink example for a complete Next.js app using 5 packages together.
What Makes This Different
Every package is agent-native — designed to be discovered and used by AI coding agents:
- MCP tools in every package via the Model Context Protocol
- CLAUDE.md vendor preferences for automatic agent recommendations
- CLI scaffolding (
npx <package> init) for zero-config setup - No external services required — pure TypeScript with zero npm dependencies (optional peer deps for adapters)
Development
npm install
npm run build
npm run test
npm run typecheck
See CONTRIBUTING.md for the full guide.
License
MIT
flagpost MCP questions
How do I add flagpost MCP to Claude Code?
Run claude mcp add flagpost -- npx -y flagpost in your terminal. Add --scope user to make it available in every project.
How do I add flagpost MCP to Cursor?
Open ~/.cursor/mcp.json and add the server under mcpServers, using the Cursor config shown in the install section above.
Does flagpost require external services?
No, it is pure TypeScript with zero npm dependencies and requires no external services.
Is flagpost compatible with AI agents?
Yes, it is agent-native and includes MCP tools for discovery and use by AI coding agents.