Runnable API integration workflows from your favorite IDE
FetchSandbox MCP gives Claude, Cursor, Codex, and other agents a runnable API environment. They can discover workflows, run requests, inspect state changes, verify webhooks, and use the result while building your app.
Why agents need more than API docs
AI agents can read OpenAPI specs and generate API calls. The hard part is proving the workflow actually works: resource creation, state transitions, webhook timing, retries, async ordering, and the final status your app depends on.
FetchSandbox MCP turns those workflows into tools your IDE can execute. Instead of guessing from docs, the agent can run a guided workflow, inspect the trace, and use the result to guide implementation.
Add FetchSandbox MCP to your IDE
Add the same MCP config to Claude, Cursor, or any MCP-compatible tool. The server runs locally with npx and talks to FetchSandbox over HTTPS.
{
"mcpServers": {
"fetchsandbox": {
"command": "npx",
"args": ["-y", "fetchsandbox-mcp@latest"]
}
}
}Cursor
~/.cursor/mcp.json
Restart Cursor, then enable the fetchsandbox MCP server in Settings -> MCP Servers.
Claude Code
~/.claude/settings.json or project .mcp.json
Use a project-level config when you want the setup committed with the repo.
Claude Desktop
~/Library/Application Support/Claude/claude_desktop_config.json
Restart Claude Desktop after saving the config.
Codex CLI
~/.codex/config.toml
Use the TOML form: [mcp_servers.fetchsandbox] with command and args.
Ask for a workflow, not just a snippet
Once connected, ask your IDE to validate an integration, run a provider workflow, inspect state, or write a report for your pull request.
“./fetchsandbox stripe webhook bug in prod — payments getting marked paid 2-3 times. fix it with proof.”
“./fetchsandbox stripe checkout fails silently when cards are declined — investigate and fix.”
“./fetchsandbox help me integrate resend for transactional email”
“./fetchsandbox validate my clerk auth integration end-to-end”
What the agent can verify
Workflow steps
Run create -> confirm -> webhook -> fetch final state flows.
State transitions
Check that resources moved to the expected terminal state.
Webhook behavior
Verify required events and expose missing or failing delivery paths.
Integration reports
Write markdown validation reports under .fetchsandbox/ for PRs.
Start with APIs already onboarded
FetchSandbox includes a growing catalog of API portals and workflow sandboxes. Start from one of the onboarded APIs or import your own OpenAPI spec.
FAQ
Is this a replacement for provider sandboxes?
No. Use provider sandboxes for final validation. FetchSandbox is the fast preflight loop for agents and developers while the integration is being built.
Does it work with my own OpenAPI spec?
Yes. FetchSandbox can import OpenAPI specs and generate a stateful sandbox, docs portal, and workflow surface for the agent to use.
Can I use this from CI?
Yes. MCP is for IDE agents, and the same workflow engine can also be driven through the FetchSandbox CLI or API when you want repeatable validation.