feat: agent node

backend/src/index.js

@@ -80,6 +80,63 @@ app.delete('/api/todos/:id', (req, res) => {
   }
 })
 
+/** POST /api/agent — run AI agent; body: { prompt, context?, contextNodes?, connection? }; returns { markdown }.
+ *  connection (from Settings): { provider, baseURL?, model?, apiKey? }. If omitted, uses env (OPENAI_API_KEY / AI_BASE_URL / AI_MODEL).
+ */
+app.post('/api/agent', async (req, res) => {
+  try {
+    const body = req.body ?? {}
+    const { prompt, context, contextNodes, connection: conn } = body
+
+    let baseURL = process.env.AI_BASE_URL?.trim() || null
+    let apiKey = process.env.OPENAI_API_KEY?.trim() || null
+    let modelId = process.env.AI_MODEL?.trim() || (baseURL ? 'local-model' : 'gpt-4o-mini')
+
+    if (conn && typeof conn === 'object') {
+      const c = conn
+      const provider = c.provider === 'openai' ? 'openai' : 'local'
+      if (provider === 'local') {
+        baseURL = (typeof c.baseURL === 'string' && c.baseURL.trim()) ? c.baseURL.trim() : baseURL
+        apiKey = (typeof c.apiKey === 'string' && c.apiKey.trim()) ? c.apiKey.trim() : (apiKey || 'lm-studio')
+      } else {
+        baseURL = null
+        apiKey = (typeof c.apiKey === 'string' && c.apiKey.trim()) ? c.apiKey.trim() : apiKey
+      }
+      if (typeof c.model === 'string' && c.model.trim()) modelId = c.model.trim()
+    }
+
+    if (!baseURL && !apiKey) {
+      return res.status(503).json({
+        error: 'No AI configured. Set connection in Settings (AI) or env: OPENAI_API_KEY or AI_BASE_URL.',
+      })
+    }
+
+    const fullPrompt = [
+      typeof prompt === 'string' ? prompt : 'No prompt provided.',
+      context && typeof context === 'string' ? `\n\nAdditional context:\n${context}` : '',
+      Array.isArray(contextNodes) && contextNodes.length > 0
+        ? `\n\nContext from connected nodes:\n${contextNodes.map((n) => (n.content != null ? n.content : `${n.id}: (no content)`)).join('\n\n')}`
+        : '',
+    ].join('')
+
+    const { generateText } = await import('ai')
+    const { createOpenAI } = await import('@ai-sdk/openai')
+    const openai = createOpenAI({
+      apiKey: apiKey || 'lm-studio',
+      ...(baseURL && { baseURL, compatibility: 'compatible' }),
+    })
+    const result = await generateText({
+      model: openai(modelId),
+      prompt: fullPrompt + '\n\nRespond with structured markdown only. No preamble.',
+    })
+    const markdown = result?.text ?? ''
+    res.json({ markdown })
+  } catch (err) {
+    console.error('Agent error:', err)
+    res.status(500).json({ error: err?.message ?? 'Agent request failed' })
+  }
+})
+
 /** Health check for Docker / orchestration */
 app.get('/health', (req, res) => {
   res.status(200).json({ ok: true })