Initial commit: Open Agent SDK (TypeScript)

Open-source Agent SDK with 30+ built-in tools, MCP integration,
multi-turn sessions, subagents, and streaming support.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

examples/web/server.ts

@@ -0,0 +1,157 @@
+/**
+ * Web Chat Server
+ *
+ * A lightweight HTTP server providing:
+ *   GET  /           — serves the chat UI
+ *   POST /api/chat   — SSE stream of agent events
+ *   POST /api/new    — resets the session
+ *
+ * Run: npx tsx examples/web/server.ts
+ */
+
+import { createServer, type IncomingMessage, type ServerResponse } from 'http'
+import { readFile } from 'fs/promises'
+import { join, dirname } from 'path'
+import { fileURLToPath } from 'url'
+import { createAgent, type Agent } from '../../src/index.js'
+
+const __dirname = dirname(fileURLToPath(import.meta.url))
+const PORT = parseInt(process.env.PORT || '8081')
+
+let agent: Agent | null = null
+
+function getOrCreateAgent(): Agent {
+  if (!agent) {
+    agent = createAgent({
+      model: process.env.CODEANY_MODEL || 'claude-sonnet-4-6',
+      maxTurns: 20,
+    })
+  }
+  return agent
+}
+
+function resetAgent(): void {
+  agent?.close().catch(() => {})
+  agent = null
+}
+
+/** Read the full request body as a string. */
+function readBody(req: IncomingMessage): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const chunks: Buffer[] = []
+    req.on('data', (c: Buffer) => chunks.push(c))
+    req.on('end', () => resolve(Buffer.concat(chunks).toString()))
+    req.on('error', reject)
+  })
+}
+
+/** Handle POST /api/chat — SSE stream */
+async function handleChat(req: IncomingMessage, res: ServerResponse) {
+  const body = JSON.parse(await readBody(req))
+  const prompt = body.message?.trim()
+  if (!prompt) {
+    res.writeHead(400, { 'Content-Type': 'application/json' })
+    res.end(JSON.stringify({ error: 'empty message' }))
+    return
+  }
+
+  // SSE headers
+  res.writeHead(200, {
+    'Content-Type': 'text/event-stream',
+    'Cache-Control': 'no-cache',
+    'Connection': 'keep-alive',
+    'X-Accel-Buffering': 'no',
+  })
+
+  const send = (event: string, data: unknown) => {
+    res.write(`data: ${JSON.stringify({ event, data })}\n\n`)
+  }
+
+  const ag = getOrCreateAgent()
+  const startMs = Date.now()
+
+  try {
+    for await (const ev of ag.query(prompt)) {
+      switch (ev.type) {
+        case 'assistant': {
+          for (const block of ev.message.content) {
+            if (block.type === 'text') {
+              send('text', { text: block.text })
+            } else if (block.type === 'tool_use') {
+              send('tool_use', {
+                id: block.id,
+                name: block.name,
+                input: block.input,
+              })
+            } else if ('thinking' in block) {
+              send('thinking', { thinking: (block as any).thinking })
+            }
+          }
+          break
+        }
+        case 'tool_result':
+          send('tool_result', {
+            tool_use_id: ev.result.tool_use_id,
+            content: ev.result.output,
+            is_error: false,
+          })
+          break
+        case 'result':
+          send('result', {
+            num_turns: ev.num_turns ?? 0,
+            input_tokens: ev.usage?.input_tokens ?? 0,
+            output_tokens: ev.usage?.output_tokens ?? 0,
+            cost: ev.total_cost_usd ?? ev.cost ?? 0,
+            duration_ms: Date.now() - startMs,
+          })
+          break
+      }
+    }
+  } catch (err: any) {
+    send('error', { message: err.message })
+  }
+
+  send('done', null)
+  res.end()
+}
+
+/** Handle POST /api/new */
+function handleNewSession(_req: IncomingMessage, res: ServerResponse) {
+  resetAgent()
+  res.writeHead(200, { 'Content-Type': 'application/json' })
+  res.end(JSON.stringify({ ok: true }))
+}
+
+/** Serve the static index.html */
+async function serveIndex(_req: IncomingMessage, res: ServerResponse) {
+  const html = await readFile(join(__dirname, 'index.html'), 'utf-8')
+  res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' })
+  res.end(html)
+}
+
+// --- HTTP Server ---
+
+const server = createServer(async (req, res) => {
+  const url = req.url || '/'
+  const method = req.method || 'GET'
+
+  try {
+    if (url === '/' && method === 'GET') return await serveIndex(req, res)
+    if (url === '/api/chat' && method === 'POST') return await handleChat(req, res)
+    if (url === '/api/new' && method === 'POST') return handleNewSession(req, res)
+
+    res.writeHead(404)
+    res.end('Not Found')
+  } catch (err: any) {
+    console.error(err)
+    if (!res.headersSent) {
+      res.writeHead(500, { 'Content-Type': 'application/json' })
+    }
+    res.end(JSON.stringify({ error: err.message }))
+  }
+})
+
+server.listen(PORT, () => {
+  console.log(`\n  Open Agent SDK — Web Chat`)
+  console.log(`  http://localhost:${PORT}\n`)
+})