Spec Driven Development
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Description from the maker (original English)
Self-hosted retrieval router for AI agents: budgets, provider routing, route receipts.
These three are never merged into one score: opinions, measurements and popularity are different things.
We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.
Pick the AI app you use, then copy the settings.
FETCHMUX_BASE_URL, FETCHMUX_API_KEYValues marked secret are keys to your account. Never share them or paste them into a chat.
You need
Which app do you use?
Pick your app above. We remember it, so next time the button says “Install in …”.
Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json
{
"mcpServers": {
"fetchmux": {
"command": "npx",
"args": [
"-y",
"@fetchmux/mcp"
],
"env": {
"FETCHMUX_BASE_URL": "your-value",
"FETCHMUX_API_KEY": "your-value"
}
}
}
}Run this in your terminal
claude mcp add fetchmux --env FETCHMUX_BASE_URL=your-value --env FETCHMUX_API_KEY=your-value -- npx -y @fetchmux/mcpFill in the empty values before running it.
Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"fetchmux": {
"command": "npx",
"args": [
"-y",
"@fetchmux/mcp"
],
"env": {
"FETCHMUX_BASE_URL": "your-value",
"FETCHMUX_API_KEY": "your-value"
}
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
Paste into .vscode/mcp.json in your project
{
"servers": {
"fetchmux": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@fetchmux/mcp"
],
"env": {
"FETCHMUX_BASE_URL": "your-value",
"FETCHMUX_API_KEY": "your-value"
}
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.
Your choice stays on this device in a cookie; no account needed.
FETCHMUX_BASE_URL envThese settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
Runs on your computer; the tool list appears in your AI app after you install it.
We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026
The registry name was verified with the GitHub account krutftw, which owns the repo
We have not read this repo from GitHub yet
We have not read this repo from GitHub yet
This one runs on your computer; there is no internet endpoint
Runs on your computer and uses local settings instead
Runs on your computer; we can only read tool lists from internet endpoints
Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.
You need to fill in: FETCHMUX_API_KEY
It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).
The GitHub repo last changed –, and the latest version (0.1.0) reached the registry 4 months ago.
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.
In the same category: Spec Driven Development, Remote Desktop Commander, Master CSS
Servers in the same category from other makers, sorted by stars.
Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.
Inspect Master CSS classes, generated CSS, and project stylesheets from your AI client.
Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.
One search endpoint for AI agents. Put a router in front of Brave, Tavily, Exa, Firecrawl, and Crossref. Every request carries a hard cost ceiling and deadline; every response comes back with a receipt that says which provider ran, why, and what it cost.
Your agents stop hard-coding a provider into prompts and app code. They send one request shape; the gateway picks an eligible provider under a policy you control, enforces the budget and deadline before the call, retries safely on failure, and returns normalized results plus a full trace. You keep your provider keys — they never leave your gateway.
Nothing is a black box. Every /v1/search response carries the routing decision:
"route": {
"selectedProvider": "brave", "attemptedProviders": ["brave"], "reasonCodes": ["TASK_MATCH", "WITHIN_BUDGET", "RELIABILITY_WEIGHT"], "attempts": [ { "provider": "brave", "outcome": "success", "latencyMs": 640, "estimatedCostUsd": 0.005 } ], "estimatedCostUsd": 0.005, "latencyMs": 640, "fallbackUsed": false, "traceId": "rt_b400e7c8" }
agent ──▶ { query · task · maxCostUsd · maxLatencyMs }
│ ▼ ┌──────────────┐ your keys │ FetchMux │ ─────▶ Brave · Tavily · Exa │ policy │ Firecrawl · Crossref └──────────────┘ ◀───── (bring your own) │ ▼ agent ◀── evidence[] + route receipt
A provider is eligible only when its credentials, task fit, circuit state, spend, and deadline all pass. Budgets and deadlines are eligibility rules, not best-effort hints. Fallback happens only on retryable failures.
No provider account needed — the public Crossref route runs out of the box:
git clone https://github.com/krutftw/fetchmux
cd fetchmux npm install npm run build
export FETCHMUX_API_KEY="a-long-random-key" export CROSSREF_ENABLED=true export CROSSREF_CONTACT_EMAIL="you@example.com" npm run dev:gateway
From another shell:
curl http://127.0.0.1:8787/v1/search \
-H "Authorization: Bearer a-long-random-key" \ -H "Content-Type: application/json" \ -d '{ "query": "retrieval augmented generation", "task": "scholarly", "maxLatencyMs": 8000 }'
To route real web search, set a provider key and use a web task instead:
export FETCHMUX_API_KEY="a-long-random-key"
export BRAVE_API_KEY="your-brave-key" export BRAVE_COST_PER_REQUEST_USD="0.005" # from your provider plan npm run dev:gateway
New to Firecrawl? New accounts get 10% off the first month through this link (referral — FetchMux earns a small commission, no extra cost to you).
Point any MCP client (Claude, Cursor, and friends) at the published server:
{
"mcpServers": { "fetchmux": { "command": "npx", "args": ["-y", "@fetchmux/mcp"], "env": { "FETCHMUX_BASE_URL": "http://127.0.0.1:8787/", "FETCHMUX_API_KEY": "your-gateway-key" } } } }
Two read-only tools: search_web and preview_search_route.
Or use the typed SDK, @fetchmux/sdk:
import { FetchMux } from "@fetchmux/sdk";
const client = new FetchMux({ baseUrl: "http://127.0.0.1:8787/", apiKey: process.env.FETCHMUX_API_KEY, fetch: globalThis.fetch.bind(globalThis), });
const res = await client.search({ query: "latest stable Node.js release", task: "fresh_facts", maxCostUsd: 0.02, });
Bring your own key for each. Set the matching *_API_KEY, plus an optional *_COST_PER_REQUEST_USD if you want dollar budgets enforced.
| Provider | Use | Key |
|---|---|---|
| Brave | web search | BRAVE_API_KEY |
| Tavily | web search, research | TAVILY_API_KEY |
| Exa | web search, docs | EXA_API_KEY |
| Firecrawl | page content | FIRECRAWL_API_KEY |
| Crossref | scholarly metadata | none (CROSSREF_ENABLED=true) |
| Method | Path | Auth | Behavior |
|---|---|---|---|
GET | /health | public | Process health and version |
GET | /ready | public | Provider readiness |
GET | /v1/providers | bearer | Provider configuration status |
POST | /v1/route/preview | bearer | Ranked candidates, no provider call |
POST | /v1/search | bearer | Routed retrieval and route receipt |
Full contract: docs/openapi.yaml.
All configuration variables
The process does not auto-load .env in local Node development; set variables in the shell or a process manager. Docker Compose reads the ignored .env file.
| Variable | Default | Purpose |
|---|---|---|
FETCHMUX_API_KEY | none | Protected-route bearer key |
FETCHMUX_API_KEYS | none | Comma-separated keys for rotation |
FETCHMUX_AUTH_DISABLED | false | Exact true bypasses auth (trusted local use only) |
FETCHMUX_ALLOWED_ORIGINS | none | Comma-separated browser origins; no CORS when empty |
FETCHMUX_HOST | 127.0.0.1 | Bind address |
FETCHMUX_PORT | 8787 | TCP port |
BRAVE_API_KEY / TAVILY_API_KEY / EXA_API_KEY / FIRECRAWL_API_KEY | none | Provider credentials |
CROSSREF_ENABLED | false | Exact true enables the credential-free scholarly route |
CROSSREF_CONTACT_EMAIL | none | Monitored contact for Crossref's polite pool |
*_COST_PER_REQUEST_USD | none | Per-provider cost estimates used by dollar budgets |
See provider configuration before enabling maxCostUsd.
cp .env.example .env # add your keys, never commit it
docker compose up --build -d curl http://127.0.0.1:8787/health
Non-root Distroless image: Linux capabilities dropped, read-only root filesystem, provider credentials passed only at container start.
Validate every case and provider pairing with no network calls or credits:
npm run benchmark -- --workload benchmarks/workloads/founding-v1.json --mode dry-run
Live mode needs provider keys and an explicit --confirm-live. Check each provider's terms before publishing results — see the benchmark methodology.
Open source, self-hosted, single-tenant, BYOK. Route events go to stdout as JSON and exclude your query text, keys, and result content by default. No database, no telemetry.
It is not a hosted service, a pooled-credit reseller, or a claim that these providers are interchangeable. Provider names are the adapters it ships with, not partnerships. A hosted version is on the roadmap — star the repo to follow.
npm test # 232 tests
npm run typecheck npm run lint npm run build npm run dev:gateway npm run dev:site
More docs: product design · local development · deployment · provider configuration · data handling · incident response
Security issues: security@fetchmux.com.
Apache-2.0. Free to self-host, modify, and redistribute.