[tanstack-ai] bug: Tree-shaking not working when importing from the top-level package

[L4Ph]

When importing a specific adapter function from the top-level package (@cloudflare/tanstack-ai), tree-shaking does not seem to work with bundlers like esbuild. As a result, unrelated adapters and their dependencies (such as @tanstack/ai-openrouter, @openrouter/sdk, @tanstack/ai-anthropic, and @tanstack/ai-grok) are bundled into the final output, unnecessarily increasing the bundle size by around 250KB.

Reproduction Steps

1. Install the package:

npm install @cloudflare/tanstack-ai@0.2.1

2. Import only a specific function (e.g., createGeminiChat) from the top level:

import { createGeminiChat } from '@cloudflare/tanstack-ai';

3. Bundle using esbuild with tree-shaking enabled:

esbuild --bundle --minify --tree-shaking=true --platform=browser --format=esm

Expected Behavior

Only createGeminiChat and its required dependencies should be bundled. Unused adapters like Anthropic, OpenRouter, and Grok should be tree-shaken out.

Actual Behavior

All available adapters are pulled into the bundle.

Currently, users have to deep-import directly from the specific adapter path to avoid this:

import { createGeminiChat } from '@cloudflare/tanstack-ai/adapters/gemini';

However, the top-level exports should ideally support proper tree-shaking without forcing deep imports.

Additional Context

This issue might be related to missing "sideEffects": false in package.json, or how the entry point is exported/compiled.

[mattzcarey]

@agent-think can you try and oneshot a pr to fix this please.