Migrate Vercel AI SDK and Eve to Pydantic AI

Preserve the application's observable behavior, not the source APIs. Vercel AI SDK Core, AI SDK UI, and Eve have different responsibilities: identify which one owns each source behavior before choosing a target.

Trace the source before choosing a target

1. Read repository instructions, dependencies, lockfiles, tests, and the runtime entrypoint. Resolve workspace:* dependencies to concrete package versions and record the installed AI SDK, Eve, Pydantic AI, and Harness versions.
2. Trace one real request from its public entrypoint through messages, model calls, tools, approvals, streams, persistence, side effects, and the result the caller consumes. Establish a focused baseline or characterization test.
3. Classify every observed contract:
   • AI SDK Core: model calls, step loops, tool execution, structured output, and provider routing;
   • AI SDK UI: UIMessage, useChat, transports, client tools, stream chunks, and reconnect behavior;
   • Eve: filesystem-defined agents, durable sessions, skills, subagents, state, connections, channels, schedules, and sandboxes;
   • Application/platform: authentication, authorization, storage, queues, deployment, credentials, product UI, and hosted Vercel services.
4. Record each contract, its owner, semantic difference, and executable proof. An unused feature is not migration scope.

Read Research and concept mapping for the detected source features. Read Verification and cutover before implementation.

Choose the smallest target