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Before anything is real

Mockd Simulate

Safe versions of the systems your agent works in. Start with HubSpot today. Each mock mirrors the real server's tools, descriptions and schemas, just with synthetic data.

claude_desktop_config.json
{
  "mcpServers": {
    "hubspot": {
      "url": "mock.mock-d.com/hubspot/mcp",
      "headers": { "x-mockd-key": "mk_test_8f2c…" }
    }
  }
}
The sandbox

A safe version of the real world

Mockd gives your agent realistic copies of the systems it will work in, copies that remember what it just did. The tools and the behaviour are the same, the risk is not. And four moves you can't make against a real account: run, break, diff, replay.

A sandbox that remembers

Create something, read it back, it's there, and it stays there the whole run long. Your agent behaves the way it would against the real system.

deals1 record
iddealnameamount
4821Acme Q3 Expansion48 000
written by
crm.deals.create
read back by
crm.deals.get

Failure rules you set up front

Rate limits, timeouts, empty answers. You decide what goes wrong and when, so how your agent copes stops being a guess.

crm.notes.create
429from call 3
crm.contacts.search
timeoutevery call

Two runs, side by side

Change something, run it again, and read step by step where the two runs part ways.

Run A
  1. search
  2. get
  3. create
  4. associate
  5. note
Run B
  1. search
  2. get
  3. create
  4. note
  5.  

diverges at step 4

The same run, once more

A finished run restarts exactly as it was, with the same state and the same failure rules. The bug reproduces instead of hiding.

same starting pointseed · rules
originalsearch · get · create · note · 429
forksearch · get · create · note · 429
The library

A growing library of ready-made mocks

One entry per system, each one a full MCP server with the real tools, descriptions and schemas behind it. HubSpot is live today, and what comes next is set by what people ask for.

What's missing?

Missing a server you need?

Tell us which MCP server to mock next, or bring your own.