Why we built Mockd

The problem with testing against the real thing

Give your agent MCP access to HubSpot, Salesforce, Slack, or anything else, and before it can do anything useful you need an account, an API key, a set of OAuth scopes, often a paid plan. Then you're one bad tool call away from creating a duplicate contact, changing a real deal, or sending a real message into a real channel.

And once it's running, you can't easily see what happened. Did the model pick the right tool? Fill the right fields? Recover when the API rate-limited it? Without dedicated tracing, you're reading logs after the fact, if you kept any.

Mockd removes the setup and adds the visibility: point your agent at a mock that looks exactly like the real server, and watch every call in a trace viewer built for MCP.

What Mockd does today

Mockd runs faithful mock MCP servers: same tool names, same descriptions, same JSON schemas as the real service, but every response is synthetic and deterministic. Your agent can't tell it isn't the real thing, and nothing it does can touch a real account.

HubSpot is live today: contacts, deals, tickets, notes and associations. Point any MCP client (Claude, Cursor, the OpenAI Agents SDK, LangGraph, or anything else that speaks MCP) at a Mockd endpoint and it behaves the way the real HubSpot MCP server would.

Every call your agent makes shows up in the trace viewer: the exact arguments, the response, the latency and the status. You can also inject failures on demand (a 429 rate limit, a timeout, an empty result, extra latency) to see whether your agent actually recovers.

What isn't part of it yet: pointing Mockd at your own MCP server. Bring Your Own MCP is being built: today Mockd mocks, and the pass-through to a real server comes after. The roadmap shows where it stands.

Getting started doesn't need an account. /try mints an anonymous, ephemeral session and hands you a ready-to-paste connection config: drop it into your MCP client, run your agent, and the first trace shows up live.

{
  "mcpServers": {
    "mockd-hubspot": {
      "url": "https://mock.mock-d.com/s/<session-token>/mcp"
    }
  }
}

Where it's going

The catalog is small on purpose: we started with HubSpot because it's the one we could make faithful end to end. The rest gets built the same way. On the roadmap:

We also want to let you compare two system prompts against the same sequence of tool calls (prompt diffing), and eventually put an accounts and pricing dashboard on top of today's login-free demo. None of that exists yet. Beyond this landing site and the /try demo, there's no platform frontend live; today it's the mock backend and this site.

We'd rather show you an honest roadmap than list features that aren't real. The full order — what's live, what's being built, what comes after — is at /roadmap. If a mock you need isn't in the catalog, tell us.

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