Let coding agents prove API workflows before they edit your app
FetchSandbox gives Claude, Cursor, Codex, and other agents a runnable API workflow environment. They can run provider flows, inspect state changes, verify webhooks, and turn that proof into implementation guidance.
The problem is not code generation
Coding agents can read docs and write API calls quickly. The risk is that an integration can compile, return a successful first response, and still miss the lifecycle your app depends on.
Real integrations have returned IDs, state transitions, webhook timing, duplicate events, failed branches, and final status checks. Agents need a place to run those workflows before they change your code.
The workflow testing loop
Discover
Find the provider workflow instead of guessing from endpoint docs.
Run
Execute the calls in order and preserve generated IDs.
Inspect
Check state changes, webhook events, and final status.
Implement
Use the proof as acceptance criteria while changing code.
Ask the agent for proof, not snippets
The best prompt asks the agent to run a provider workflow first, then turn the trace into acceptance criteria for the implementation.
“Before editing code, run the Stripe checkout workflow and list the state and webhook events my app must handle.”
“Use FetchSandbox to test this Twilio status callback path, then tell me where the app needs reconciliation.”
“Discover the Paddle subscription workflows and write acceptance criteria before implementing billing.”
What FetchSandbox gives the agent
- Runnable provider workflows instead of static examples.
- Stateful resources, so a create call can be read back later.
- Webhook events tied to actual workflow transitions.
- Request/response traces the agent can summarize before editing files.
- Markdown validation reports for PRs and implementation notes.
Start here
Configure FetchSandbox MCP once, then ask your agent to run a workflow before implementing the next provider integration.