mcp-query ecosystem

A data-layer ecosystem for the Model Context Protocol — a reactive client and the governance, testing, and fixture tooling built around it. Same shape as the GraphQL world (Apollo Client + a gateway + schema checks + mocking), but for MCP.

This repo is an npm-workspaces monorepo. The packages share one core (mcp-query) and compose along a clean seam (an interceptor chain + a transport tap), so each does one job and they stack:

                          ┌─────────────────────────────────────────────┐
 your app / agent host ──▶│                 mcp-query                    │──▶ MCP servers
                          │   reactive client · cache · codegen · core   │
                          └─────────────────────────────────────────────┘
                                              ▲
      ┌──────────┬──────────┬──────────┬───────┴──┬──────────┬──────────┐
 ┌─────────┐ ┌────────┐ ┌────────┐ ┌────────┐ ┌────────┐ ┌────────┐
 │ mcp-gate│ │contract│ │  lint  │ │  docs  │ │  bench │ │ record │
 │ govern  │ │ guard  │ │ lint   │ │generate│ │ measure│ │ freeze │
 │ runtime │ │ drift  │ │ quality│ │ref docs│ │ latency│ │ traffic│
 └─────────┘ └────────┘ └────────┘ └────────┘ └────────┘ └────────┘
              └──────── share capture / connect (the surface) ───────┘

Packages

Package	What it does	When you reach for it
@mcp-query/cli	The unified mcpq CLI: one entry point over every tool below (mcpq lint/docs/bench/…), plus a server registry (mcpq add, honoring the .mcp.json/mcpServers standard) and client verbs (mcpq tools/call/read) to drive any registered server.	You want one command for the whole toolkit and to call your MCP servers by name from the terminal.
mcp-query	The reactive, cached, embeddable MCP client: TanStack-Query-style document cache, RTK-Query tags, LSP-client lifecycle, React hooks, codegen, an interceptor chain, and optional server-side modules (gateway, metrics, OTel, sessions, Redis L2).	You're consuming MCP servers from an app or backend and want a real data layer, not raw SDK calls.
@mcp-query/gate	A config-driven security/policy proxy. Fronts many upstreams as one governed endpoint: declarative authorization, DLP redaction, rate-limit, circuit-breaking, audit.	You're handing MCP servers to an agent and need a runtime choke point — allow/deny, scrub secrets, log everything.
@mcp-query/contract	Contract testing / drift detection. Pin a server's capability surface, then fail CI when a live server changes incompatibly (with proper input/output variance). The dual of codegen.	You generated/wrote code against an MCP server and want CI to catch breaking drift before it ships.
@mcp-query/lint	Quality lint (ESLint for MCP). Check a single surface against design rules — descriptions, annotations, typed inputs, naming — and gate CI on it.	You're authoring an MCP server and want a quality bar enforced in CI.
@mcp-query/docs	Reference docs (Redoc for MCP). Render Markdown docs from a live server or a contract: tool arg tables, annotation badges, resources, prompts.	You want always-current reference docs for an MCP server, generated not hand-written.
@mcp-query/bench	Benchmarking. Latency (p50/p95/p99) + throughput per tool, with perf budgets that fail CI. Local or hosted servers.	You want to track an MCP server's performance or gate on a latency budget.
@mcp-query/record	Record / replay (VCR for MCP). Capture real server traffic to a cassette, replay it offline as a deterministic mock.	Your tests/demos need a server's real output but fast, offline, and frozen.

Apps

Reference applications that prove you can build real product UIs on MCP — each chosen to exploit a different MCP-native capability REST/GraphQL lack. They share a spine (apps/shared: the WS proxy, transport, OAuth, schema-form, and React glue).

App	What it shows	Stack
inspector	Protocol debugger — raw message log, manual sampling, OAuth stepper, cache view	Web Components
socialgpt-studio	One backend, two consumers — a creator-analytics UI over the live OAuth-gated SocialGPT tool surface an agent also uses	React, Deno desktop (+ token-injecting backend proxy)
console	Capability discovery — a polished operator UI auto-generated from any server's tools/resources/prompts	Web Components
ops-cockpit	Aggregation + live tiles — a NOC dashboard over many servers, reactive on health + list_changed	React
approvals	Human-in-the-loop — agent sampling/elicitation proposals approved/edited in a queue, on the InteractionBroker	React
notebook	Subscriptions — a notes UI where agent and app share one live view via resources/subscribe	React
composer	Tools as input — a chat where the user drives MCP tools to assemble grounded input (the inverse of agentic tool use), with a pluggable model picker via ai.matey	React
prompt-studio	Prompts as a product surface — run server prompts with live completion/complete typeahead (incl. dependent completions), expand resource templates into subscribed reads, over codegen-typed hooks	React
switchboard	One governed endpoint, many tenants — an @mcp-query/gate sidecar fronting local + live remote upstreams, an interceptor trace waterfall, and per-tenant cache partitions via client.scope()	React

Browser apps reach stdio servers through apps/shared's WebSocket proxy (the dev script runs it alongside Vite); the React apps dogfood mcp-query's React hooks, the Web-Components apps the framework-agnostic core.

ops-cockpit — a NOC dashboard with live health tiles over many servers at once.	socialgpt-studio — creator analytics over a live, OAuth-gated MCP server.
inspector — a protocol debugger with the raw JSON-RPC message log.	composer — tools as input: a user-driven, grounded chat.

Each app's README has a full Screenshots section.

How they relate

• One core, composable seams. mcp-gate is just mcp-query's MCPClient behind its createGateway, with an interceptor stack. mcp-record taps the same instrumentTransport seam the devtools use. mcp-contract's mock and mcp-record's replay both build on the shared MockMCPServer.
• One capture, four uses. mcp-contract captures a server's surface; mcp-lint and mcp-docs reuse that same captureContract — to grade the surface and to document it. Pin it (contract), lint it (lint), document it (docs).
• contract vs lint: contract is relative (did it change incompatibly between two versions?); lint is absolute (is this one version well-designed?). Run both in CI.
• contract vs record: a contract pins the shape (schemas/annotations) to catch drift; a cassette freezes the real results for offline replay. Use both — contract in CI, cassettes in tests.

The mcpq CLI

One entry point over the whole toolkit, a server registry, and a terminal MCP client:

# register a server once (stdio or hosted; honors ~/.mcp-query/servers.json + project .mcp.json)
mcpq add everything --command npx --args "-y @modelcontextprotocol/server-everything"
mcpq add linear https://mcp.linear.app/mcp        # hosted
mcpq login linear                                  # browser OAuth (DCR+PKCE), token cached + auto-refreshed
mcpq servers                                       # list them
mcpq import claude                                 # pull servers from Claude/Cursor/VS Code configs

# drive any registered server (by name) from the terminal
mcpq tools everything                              # list tools as typed signatures
mcpq call everything echo --message hi             # flag style …
mcpq call everything 'get-sum(a: 2, b: 40)'        # … or function-call style (coerced by inputSchema)
mcpq read everything file:///x   ·   mcpq ping everything
mcpq session everything                            # interactive REPL on ONE live connection
mcpq call --daemon everything echo --message hi    # keep-alive daemon reuses the connection
mcpq daemon status   ·   mcpq daemon stop          # across invocations (great for stateful stdio servers)

# every tool is a verb — and accepts a registered name
mcpq lint everything   ·   mcpq docs linear --out API.md   ·   mcpq bench everything --call echo:'{}'
mcpq contract snapshot everything --out api.json   ·   mcpq gate ./gate.config.ts

.mcp.json/mcpServers configs from Claude, Cursor, and VS Code are read natively (no secrets stored — OAuth lives in ~/.mcp-query/oauth/). The individual mcp-* bins still work standalone.

Develop

npm install                 # install all workspaces

npm test                    # run every workspace's test suite
npm run build               # build the publishable mcp-query package (dist/)
npm run typecheck           # typecheck all workspaces

# work in one package
npm test -w mcp-query
npm test -w @mcp-query/gate
npm run dev -w @mcp-query/inspector

In this monorepo the satellite packages consume mcp-query directly from its TypeScript source (packages/mcp-query/src) for a zero-build dev loop; only mcp-query itself emits a dist/ for publishing.

Status

mcp-query is the publishable core (0.0.1); the gate / contract / lint / docs / bench / record packages and the inspector are MVPs (private) tracking it. See each package's README for specifics.

License

MIT