Vite auto-instrumentation renames wrapped classes, mangling span names #24696

Summary

Under zero config (sentryCloudflareVitePlugin()), a wrapped class reports its name as __SENTRY_ORIGINAL_<Name>__ at runtime. Anything that reads Class.name shows that placeholder: a @cloudflare/think agent span reads invoke_agent __SENTRY_ORIGINAL_ThinkAgent__ with gen_ai.function_id to match, and agents puts it in gen_ai.agent.name. Applies to every class the plugin wraps (Durable Objects, Agents, Workflows, WorkerEntrypoints). Manual instrument*WithSentry is unaffected.

Root cause

packages/cloudflare/src/vite/transform.ts frees the export binding for the wrapper by renaming the user's class declaration:

class __SENTRY_ORIGINAL_ThinkAgent__ extends Think {}
export const ThinkAgent = instrumentAgentWithSentry(opts, __SENTRY_ORIGINAL_ThinkAgent__);

Renaming a declaration changes Function.prototype.name. Think passes this.constructor.name to the AI SDK as functionId, which the vercel-ai subscriber uses as the span name.

Fix: leave the declaration alone and alias the export instead, the shape the plugin already emits for cross-module re-exports and the docs show for manual wrapping:

class ThinkAgent extends Think {}
const __SENTRY_WRAPPED_ThinkAgent__ = instrumentAgentWithSentry(opts, ThinkAgent);
export { __SENTRY_WRAPPED_ThinkAgent__ as ThinkAgent };

Environment

• @sentry/cloudflare 10.67.0, @cloudflare/vite-plugin 1.57.2
• @cloudflare/think 0.19.0, ai 7, agents 0.24
• Reproduced on a local worker with the cloudflare-think e2e app