fix: use sync rate limiter for conversation routes

The distributed rate limiter (checkRateLimitDistributed) was causing
timeouts in production, likely due to @vercel/kv connection issues.
Switch to sync in-memory rate limiter (checkRateLimit) which works
reliably across all other endpoints.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/app/api/agents/[id]/conversation/[conversationId]/route.ts

@@ -14,7 +14,7 @@ import type { AIProvider } from '@tpmjs/types/agent';
 import { SendMessageSchema } from '@tpmjs/types/agent';
 import type { LanguageModel, ModelMessage } from 'ai';
 import { type NextRequest, NextResponse } from 'next/server';
-import { type RateLimitConfig, checkRateLimitDistributed } from '~/lib/rate-limit';
+import { type RateLimitConfig, checkRateLimit } from '~/lib/rate-limit';
 
 /**
  * Rate limit for chat messages: 30 requests per minute
@@ -72,8 +72,8 @@ async function getProviderModel(
  * Send a message and stream the AI response via SSE
  */
 export async function POST(request: NextRequest, context: RouteContext): Promise<Response> {
-  // Check rate limit first to prevent expensive LLM calls (uses distributed KV when available)
-  const rateLimitResponse = await checkRateLimitDistributed(request, CHAT_RATE_LIMIT);
+  // Check rate limit first to prevent expensive LLM calls
+  const rateLimitResponse = checkRateLimit(request, CHAT_RATE_LIMIT);
   if (rateLimitResponse) {
     return rateLimitResponse;
   }

apps/web/src/app/api/agents/[username]/[uid]/conversation/[conversationId]/route.ts

@@ -14,7 +14,7 @@ import type { AIProvider } from '@tpmjs/types/agent';
 import { SendMessageSchema } from '@tpmjs/types/agent';
 import type { LanguageModel, ModelMessage } from 'ai';
 import { type NextRequest, NextResponse } from 'next/server';
-import { type RateLimitConfig, checkRateLimitDistributed } from '~/lib/rate-limit';
+import { type RateLimitConfig, checkRateLimit } from '~/lib/rate-limit';
 
 /**
  * Rate limit for chat messages: 30 requests per minute
@@ -85,8 +85,8 @@ async function getProviderModel(
  * Send a message and stream the AI response via SSE
  */
 export async function POST(request: NextRequest, context: RouteContext): Promise<Response> {
-  // Check rate limit first to prevent expensive LLM calls (uses distributed KV when available)
-  const rateLimitResponse = await checkRateLimitDistributed(request, CHAT_RATE_LIMIT);
+  // Check rate limit first to prevent expensive LLM calls
+  const rateLimitResponse = checkRateLimit(request, CHAT_RATE_LIMIT);
   if (rateLimitResponse) {
     return rateLimitResponse;
   }

docs/vercel-sandbox-api-question.md

@@ -0,0 +1,148 @@
+# Vercel Sandbox SDK API Research Request
+
+## Context
+
+We're building a TPMJS executor template that runs npm packages in isolated Vercel Sandbox VMs. The executor needs to:
+
+1. Create a sandbox VM
+2. Install an npm package (`npm install @tpmjs/hello@latest`)
+3. Write a Node.js script file to the sandbox
+4. Execute the script and capture stdout/stderr
+5. Parse the output and return results
+6. Clean up the sandbox
+
+## Current Problem
+
+Our code assumes the `@vercel/sandbox` SDK has this API:
+
+```typescript
+import { Sandbox } from '@vercel/sandbox';
+
+const sandbox = await Sandbox.create({
+  runtime: 'node22',
+  timeout: 2 * 60 * 1000,
+});
+
+// We assumed this signature:
+await sandbox.runCommand({
+  cmd: 'npm',
+  args: ['install', '--no-save', packageSpec],
+  cwd: '/vercel/sandbox',
+  stdout: someWritableStream,
+  stderr: someWritableStream,
+});
+
+await sandbox.writeFiles([
+  { path: '/vercel/sandbox/execute.cjs', content: Buffer.from(script) },
+]);
+
+await sandbox.stop();
+```
+
+But TypeScript is telling us the actual signature is:
+
+```
+Overload 1 of 3: (command: string, args?: string[], opts?: { signal?: AbortSignal }) => Promise<CommandFinished>
+```
+
+## Questions to Research
+
+### 1. What is the exact `@vercel/sandbox` SDK API?
+
+We need the **current, accurate API** for version `^1.1.5` of `@vercel/sandbox`:
+
+- `Sandbox.create()` - What options does it accept?
+- How do you run commands? What's the method signature?
+- How do you capture stdout/stderr from commands?
+- How do you write files to the sandbox?
+- How do you read files from the sandbox?
+- How do you stop/destroy the sandbox?
+
+### 2. What is the correct way to run commands and capture output?
+
+Our use case:
+```typescript
+// Install npm package
+await sandbox.???('npm install @tpmjs/hello@latest');
+
+// Run a script and capture output
+const result = await sandbox.???('node execute.cjs');
+console.log(result.stdout); // Need this
+console.log(result.stderr); // Need this
+```
+
+### 3. What is the correct way to write files?
+
+We need to write a JavaScript file to the sandbox filesystem:
+```typescript
+const script = `
+  const pkg = require('@tpmjs/hello');
+  const result = await pkg.helloWorld.execute({ name: 'World' });
+  console.log(JSON.stringify({ result }));
+`;
+
+await sandbox.???('/path/to/script.js', script);
+```
+
+### 4. What is the default working directory?
+
+- Where does the sandbox start?
+- Where should we install npm packages?
+- What directories are writable?
+
+### 5. Complete working example
+
+Please provide a complete, working example that:
+1. Creates a sandbox
+2. Installs an npm package
+3. Writes a script file
+4. Runs the script
+5. Captures and returns stdout
+6. Cleans up
+
+## Reference Links
+
+- npm package: https://www.npmjs.com/package/@vercel/sandbox
+- Vercel Sandbox docs: https://vercel.com/docs/vercel-sandbox
+- Vercel Sandbox SDK reference: https://vercel.com/docs/vercel-sandbox/reference/classes/sandbox
+
+## Expected Output
+
+A corrected version of this code that actually compiles and works:
+
+```typescript
+import { Sandbox } from '@vercel/sandbox';
+
+export async function executeTool(packageName: string, toolName: string, params: object) {
+  const sandbox = await Sandbox.create({ runtime: 'node22' });
+
+  try {
+    // Install package
+    await sandbox./* correct method */('npm install ' + packageName);
+
+    // Write script
+    const script = `
+      const pkg = require('${packageName}');
+      const result = await pkg['${toolName}'].execute(${JSON.stringify(params)});
+      console.log(JSON.stringify({ __result__: result }));
+    `;
+    await sandbox./* correct method */('/script.cjs', script);
+
+    // Execute and capture output
+    const result = await sandbox./* correct method */('node /script.cjs');
+
+    // Parse output
+    const output = JSON.parse(result.stdout);
+    return output.__result__;
+  } finally {
+    await sandbox.stop();
+  }
+}
+```
+
+## Our Environment
+
+- `@vercel/sandbox`: ^1.1.5
+- Next.js: ^15.0.0
+- TypeScript: ^5.6.0
+- Deploying to Vercel