Error when sending message without `ANTHROPIC_API_KEY`: "x-api-key header is required"

[its-DeFine]

Error when sending message without ANTHROPIC_API_KEY: "x-api-key header is required"

Description

When installing Eliza from source and running bun start, attempts to send a message to the agent fail with an AI_APICallError: x-api-key header is required error if the ANTHROPIC_API_KEY environment variable is not set. This occurs regardless of whether an OPENAI_API_KEY is present.

Steps to Reproduce

1. Clone the Eliza repository and install dependencies.
2. Ensure only the OPENAI_API_KEY (or no API keys) is set in your environment; do not set ANTHROPIC_API_KEY.
3. From the project root, run:

   bun start
   

4. Attempt to send a message to the “Eliza” agent (e.g., via an HTTP request or CLI).
5. Observe the error in logs.

Expected Behavior

• If ANTHROPIC_API_KEY is unset, Eliza should either:
  • Fall back to OpenAI if OPENAI_API_KEY is provided, or
  • Emit a warning about missing Anthropic functionality without throwing an error when handling messages.

Actual Behavior

Eliza logs warnings about missing instrumentation and missing ANTHROPIC_API_KEY, then errors out on any message send with:

(AI_APICallError) x-api-key header is required
at new _AISDKError (/eliza/node_modules/@ai-sdk/provider/dist/index.mjs:19:5)
...

Relevant Logs

[2025-04-23 22:20:42] WARN: ANTHROPIC_API_KEY is not set in environment - Anthropic functionality will be limited
[2025-04-23 22:20:47] WARN: Service instrumentation not found
    agentName: "Eliza"
    agentId: "b850bc30-45f8-0041-a00a-83df46d8555d"
[2025-04-23 22:20:47] WARN: [getTracer] Service instrumentation not found in runtime.
[2025-04-23 22:20:48] ERROR: Error during emitEvent for MESSAGE_RECEIVED (handler execution):
    agentName: "Eliza"
    agentId: "b850bc30-45f8-0041-a00a-83df46d8555d"
    message: "(AI_APICallError) x-api-key header is required"
    stack: [
      "AI_APICallError: x-api-key header is required",
      "at new _AISDKError (/eliza/node_modules/@ai-sdk/provider/dist/index.mjs:19:5)",
      "at new APICallError (/eliza/node_modules/@ai-sdk/provider/dist/index.mjs:61:5)",
      "at <anonymous> (/eliza/node_modules/@ai-sdk/provider-utils/dist/index.mjs:667:18)",
      "at processTicksAndRejections (native:7:39)"
    ]

Environment

• OS: Ubuntu 22.04 LTS
• Runtime: Bun v0.x
• Eliza Version: Source checkout as of April 23, 2025
• Env Vars:
  • OPENAI_API_KEY: set or unset
  • ANTHROPIC_API_KEY: not set

Additional Context

This issue blocks users who wish to run Eliza exclusively with OpenAI credentials. A fallback or clearer error message would improve usability.