MCP server

FetchSandbox Official

io.github.fetchsandbox/mcp

Checked 25 Oct 2026, 20:29 UTC · Connected to it and listed its tools

A deterministic verification engine for agents. Proves a fix: fails on the old code, passes on new.

Website Source

At a glance

Type

MCP server

Publisher

fetchsandbox.com (verified by the MCP Registry)

Status

Working at last check

Tools

8

Token cost

About 9,372 tokens per request

Sets up in

Claude Code, Claude Desktop, Codex, Gemini CLI, Cursor, VS Code, Antigravity, ChatGPT, OpenAI API, Grok

Last checked

25 Oct 2026, 20:29 UTC

Connect it to your agent

Add to CursorAdd to VS CodeVS Code Insiders

Opens the app, which shows the server and asks you to confirm. For other apps, copy the setup below.

Claude Code

claude mcp add --transport http fetchsandbox https://fetchsandbox.com/mcp/v1

Claude Desktop

Settings → Connectors → Add custom connector, and paste the URL.

Codex (config.toml)

[mcp_servers.fetchsandbox]
url = "https://fetchsandbox.com/mcp/v1"

Gemini CLI

{"mcpServers":{"fetchsandbox":{"httpUrl":"https://fetchsandbox.com/mcp/v1"}}}

Cursor

{"mcpServers":{"fetchsandbox":{"url":"https://fetchsandbox.com/mcp/v1"}}}

VS Code

{"servers":{"fetchsandbox":{"type":"http","url":"https://fetchsandbox.com/mcp/v1"}}}

Antigravity

agy mcp add fetchsandbox https://fetchsandbox.com/mcp/v1

ChatGPT

Settings → Apps & Connectors → Advanced settings: turn on Developer mode, then Create a connector and paste the URL. Which plans can do this varies.

OpenAI API (Responses tools)

{"type":"mcp","server_label":"fetchsandbox","server_url":"https://fetchsandbox.com/mcp/v1","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"fetchsandbox","server_url":"https://fetchsandbox.com/mcp/v1"}

Tools

• coach ~794 tokens
  Conversational integration coach for FetchSandbox. Server-side orchestrator that walks the user through adding an API integration (payments / email / auth / etc.) — intake the goal, elicit domain-aware discovery questions from the spec's brain.yaml, route to the right workflow, prove the contract vi
• get_job ~170 tokens
  Retrieve the SAME running find_bugs, fix_bug, prove_fix, verify_behavior or validate_integration job (including requirements planning). Follow next_tool_call until status is done or error. Never restart the original tool to poll. A proposed plan is not execution proof; a running response is not proo
• guide ~419 tokens
  ROUTE a symptom to the provider behaviour that explains it. Use this when the user names a provider or a domain (payments, email, auth, SMS, subscriptions) and you need to know what that provider ACTUALLY does — not what its docs say, and not what can be inferred from reading the integration code. R
• list_workflows ~518 tokens
  List the named, runnable workflows for a known provider slug or imported spec. Workflows are realistic multi-step API journeys (e.g. 'create customer → attach payment method → create subscription'). Known provider slugs need no import. Use this for exploration ("what can I do?", "show me the flows")
• quickrun ~433 tokens
  Run a curated reference workflow against a KNOWN, bundled spec (stripe, clerk, descope, resend, twilio, and 50+ others) in ONE call — it spins up the sandbox by slug, so you do NOT need import_spec or a sandbox_id first. Use this when exploring the bundled provider contract: call `guide` on their pr
• run_workflow ~487 tokens
  Execute ONE specific workflow by name and return its step-by-step trace PLUS a `share_url` — a public, replayable proof URL that renders the full timeline (every request, response, webhook event) for this run. The share_url is the canonical 'here's what happened' artifact: surface it verbatim in any
• validate_integration ~6023 tokens
  Completion rule: a request to verify an app includes its applicable failure checks without another user prompt. When verification_continuation.required is true, continue in this agent: inspect pending_checks, preserve every declared check and its assertions, implement supported actions, and rerun a
• verify_behavior ~528 tokens
  Prove a known fix survives a bug — the 'prove' half of reproduce→prove. The backend spawns a buggy AND a fixed reference handler and fires the bug_pattern's probes at both, returning the side-by-side diff (e.g. the buggy handler double-charges on a duplicate webhook, the fixed handler dedupes). Call

Browse

• GitHub tools
• Stripe tools
• Email
• SMS and text messages
• Team chat
• Phone calls

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