Keep your agent. Change one endpoint.

1. Step 1

   Set the base URL and key

   Keep both in your shell or secret store. Send the key in a header, never in the request body.

   export FLEX_BASE_URL="https://api.adhibita.com"      # scheme and host from your invitation
   export MUSCLE_FLEX_API_KEY="<FLEX_API_KEY>"  # from the API keys page of the portal

2. Step 2

   Check the key without spending credits

   The account endpoint is never charged. It returns your available credits and the last four characters of the key.

   curl -i "$FLEX_BASE_URL/v1/account" \
     -H "Authorization: Bearer $MUSCLE_FLEX_API_KEY"

3. Step 3

   Send a request with your SDK

   Use the OpenAI SDK against /v1 or the Anthropic SDK against the host. Each response carries an X-Request-Id header; save it for support.

   import OpenAI from "openai";
   
   const flex = new OpenAI({
     apiKey: process.env.MUSCLE_FLEX_API_KEY,
     baseURL: `${process.env.FLEX_BASE_URL}/v1`,
   });
   
   const completion = await flex.chat.completions.create({
     model: "muscle/auto",
     messages: [
       { role: "user", content: "Summarize the failure mode in this test output." },
     ],
   });
   
   console.log(completion.choices[0]?.message.content);

   import Anthropic from "@anthropic-ai/sdk";
   
   const flex = new Anthropic({
     apiKey: process.env.MUSCLE_FLEX_API_KEY,
     baseURL: process.env.FLEX_BASE_URL, // host only; the SDK adds /v1
   });
   
   const message = await flex.messages.create({
     model: "muscle/auto",
     max_tokens: 1024,
     messages: [
       { role: "user", content: "Summarize the failure mode in this test output." },
     ],
   });
   
   console.log(message.content);

4. Step 4

   Or configure a tested coding agent

   Each agent has a setup page with the exact configuration, a key check and one tool call to verify it. These configurations passed on the Flex build recorded for each one in the compatibility matrix.

   • Claude CodeAnthropic Messages
   • Codex CLIResponses
   • opencodeChat Completions
   • CrushChat Completions

The SDK examples are illustrative. The SDK request surfaces are still Pending in the compatibility matrix; the four coding-agent setups above have passed on the builds recorded there. Streaming, tools and every field Flex accepts or rejects are covered in the API reference.