feat: Step 10 - Node Editor & AI-Powered Linking

Implemented the node editor page and AI-powered link suggestions:

1. Node Editor Page (/editor/[id]):
   - Form with title and body fields using Mantine
   - Pre-fill support from query params (for chat redirects)
   - "Find Related" button to discover similar nodes
   - "Publish Node" button to save to ATproto + SurrealDB
   - Display of suggested links with similarity scores
   - Mantine notifications for success/error feedback

2. Suggest Links API (/api/suggest-links):
   - Authenticates using SurrealDB JWT cookie
   - Generates embedding for draft text using Google AI
   - Performs vector similarity search using SurrealDB
   - Returns top 5 most similar nodes with cosine scores
   - Enforces row-level security (users only see their nodes)

3. Magnitude Tests:
   - Editor page rendering
   - Pre-filled form from query params
   - Publishing new nodes
   - Form validation

The editor integrates with the existing /api/nodes write-through
cache from Step 6, completing the node creation workflow.

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

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

app/api/suggest-links/route.ts

@@ -0,0 +1,74 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { cookies } from 'next/headers';
+import { connectToDB } from '@/lib/db';
+import { generateEmbedding } from '@/lib/ai';
+
+/**
+ * POST /api/suggest-links
+ *
+ * Uses vector similarity search to find related nodes.
+ * Takes the body text of a draft node, generates an embedding,
+ * and returns the top 5 most similar nodes using cosine similarity.
+ */
+export async function POST(request: NextRequest) {
+  const cookieStore = await cookies();
+  const surrealJwt = cookieStore.get('ponderants-auth')?.value;
+
+  if (!surrealJwt) {
+    return NextResponse.json({ error: 'Not authenticated' }, { status: 401 });
+  }
+
+  const { body } = (await request.json()) as { body: string };
+
+  if (!body) {
+    return NextResponse.json({ error: 'Body text is required' }, { status: 400 });
+  }
+
+  try {
+    // 1. Generate embedding for the current draft
+    const draftEmbedding = await generateEmbedding(body);
+
+    // 2. Connect to DB (as the user)
+    // This enforces row-level security - user can only search their own nodes
+    const db = await connectToDB(surrealJwt);
+
+    // 3. Run the vector similarity search query
+    // This query finds the 5 closest nodes in the 'node' table
+    // using cosine similarity on the 'embedding' field.
+    // It only searches nodes WHERE user_did = $token.did,
+    // which is enforced by the table's PERMISSIONS.
+    const query = `
+      SELECT
+        id,
+        title,
+        body,
+        atp_uri,
+        vector::similarity::cosine(embedding, $draft_embedding) AS score
+      FROM node
+      ORDER BY score DESC
+      LIMIT 5;
+    `;
+
+    const results = await db.query<[Array<{
+      id: string;
+      title: string;
+      body: string;
+      atp_uri: string;
+      score: number;
+    }>]>(query, {
+      draft_embedding: draftEmbedding,
+    });
+
+    // The query returns an array of result sets. We want the first one.
+    const suggestions = results[0] || [];
+
+    return NextResponse.json(suggestions);
+
+  } catch (error) {
+    console.error('[Suggest Links] Error:', error);
+    return NextResponse.json(
+      { error: 'Failed to suggest links' },
+      { status: 500 }
+    );
+  }
+}

app/editor/[id]/page.tsx

@@ -0,0 +1,187 @@
+'use client';
+
+import {
+  Container,
+  Title,
+  TextInput,
+  Textarea,
+  Button,
+  Stack,
+  Paper,
+  Text,
+  LoadingOverlay,
+  Group,
+} from '@mantine/core';
+import { useForm } from '@mantine/form';
+import { useSearchParams, useRouter, useParams } from 'next/navigation';
+import { useEffect, useState } from 'react';
+import { notifications } from '@mantine/notifications';
+
+// Define the shape of a suggested link
+interface SuggestedNode {
+  id: string;
+  title: string;
+  body: string;
+  score: number;
+}
+
+export default function EditorPage() {
+  const router = useRouter();
+  const params = useParams();
+  const searchParams = useSearchParams();
+
+  const [isPublishing, setIsPublishing] = useState(false);
+  const [isFinding, setIsFinding] = useState(false);
+  const [suggestions, setSuggestions] = useState<SuggestedNode[]>([]);
+
+  const form = useForm({
+    initialValues: {
+      title: '',
+      body: '',
+      links: [] as string[], // Array of at-uri strings
+    },
+  });
+
+  // Pre-fill form from search params (from AI chat redirect)
+  useEffect(() => {
+    if (params.id === 'new') {
+      const title = searchParams.get('title') || '';
+      const body = searchParams.get('body') || '';
+      form.setValues({ title, body });
+    } else {
+      // TODO: Load existing node from /api/nodes/[id]
+    }
+  }, [params.id, searchParams]);
+
+  // Handler for the "Publish" button (calls Commit 06 API)
+  const handlePublish = async (values: typeof form.values) => {
+    setIsPublishing(true);
+    try {
+      const response = await fetch('/api/nodes', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(values),
+      });
+
+      if (!response.ok) {
+        const error = await response.json();
+        throw new Error(error.error || 'Failed to publish node');
+      }
+
+      const newNode = await response.json();
+
+      notifications.show({
+        title: 'Success',
+        message: 'Node published successfully!',
+        color: 'green',
+      });
+
+      // On success, go to the chat (galaxy not implemented yet)
+      router.push('/chat');
+
+    } catch (error) {
+      console.error(error);
+      notifications.show({
+        title: 'Error',
+        message: error instanceof Error ? error.message : 'Failed to publish node',
+        color: 'red',
+      });
+    } finally {
+      setIsPublishing(false);
+    }
+  };
+
+  // Handler for the "Find related" button
+  const handleFindRelated = async () => {
+    setIsFinding(true);
+    setSuggestions([]);
+    try {
+      const response = await fetch('/api/suggest-links', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ body: form.values.body }),
+      });
+
+      if (!response.ok) {
+        const error = await response.json();
+        throw new Error(error.error || 'Failed to find links');
+      }
+
+      const relatedNodes = await response.json();
+      setSuggestions(relatedNodes);
+
+    } catch (error) {
+      console.error(error);
+      notifications.show({
+        title: 'Error',
+        message: error instanceof Error ? error.message : 'Failed to find related links',
+        color: 'red',
+      });
+    } finally {
+      setIsFinding(false);
+    }
+  };
+
+  return (
+    <Container size="md" py="xl">
+      <form onSubmit={form.onSubmit(handlePublish)}>
+        <Stack gap="md">
+          <Title order={2}>
+            {params.id === 'new' ? 'Create New Node' : 'Edit Node'}
+          </Title>
+
+          <TextInput
+            label="Title"
+            placeholder="Your node title"
+            required
+            {...form.getInputProps('title')}
+          />
+
+          <Textarea
+            label="Body"
+            placeholder="Your node content..."
+            required
+            minRows={10}
+            autosize
+            {...form.getInputProps('body')}
+          />
+
+          <Group>
+            <Button
+              type="button"
+              variant="outline"
+              onClick={handleFindRelated}
+              loading={isFinding}
+            >
+              Find Related
+            </Button>
+            <Button type="submit" loading={isPublishing}>
+              Publish Node
+            </Button>
+          </Group>
+
+          {/* Related Links Section */}
+          <Stack>
+            {isFinding && <LoadingOverlay visible />}
+            {suggestions.length > 0 && <Title order={4}>Suggested Links</Title>}
+
+            {suggestions.map((node) => (
+              <Paper key={node.id} withBorder p="sm">
+                <Text fw={700}>{node.title}</Text>
+                <Text size="sm" lineClamp={2}>{node.body}</Text>
+                <Text size="xs" c="dimmed">Similarity: {(node.score * 100).toFixed(0)}%</Text>
+              </Paper>
+            ))}
+
+            {!isFinding && suggestions.length === 0 && form.values.body && (
+              <Text size="sm" c="dimmed">
+                Click "Find Related" to discover similar nodes
+              </Text>
+            )}
+          </Stack>
+
+        </Stack>
+      </form>
+    </Container>
+  );
+}

tests/magnitude/10-linking.mag.ts

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+import { test } from 'magnitude-test';
+
+test('Editor page renders correctly', async (agent) => {
+  await agent.act('Navigate to /editor/new');
+  await agent.check('The text "Create New Node" is visible on the screen');
+  await agent.check('A text input field labeled "Title" is visible');
+  await agent.check('A textarea labeled "Body" is visible');
+  await agent.check('A button labeled "Find Related" is visible');
+  await agent.check('A button labeled "Publish Node" is visible');
+});
+
+test('[Happy Path] User can navigate to editor from chat', async (agent) => {
+  // Simulate pre-filled form from chat redirect
+  await agent.act('Navigate to /editor/new?title=My%20Idea&body=This%20is%20my%20thought');
+  await agent.check('The "Title" input contains "My Idea"');
+  await agent.check('The "Body" textarea contains "This is my thought"');
+});
+
+test('[Happy Path] User can fill out and publish a new node', async (agent) => {
+  // Navigate to the editor
+  await agent.act('Navigate to /editor/new');
+
+  // Fill out the form
+  await agent.act('Type "My First Published Node" into the "Title" input');
+  await agent.act('Type "This is the body of my first node. It contains interesting thoughts about technology and innovation." into the "Body" textarea');
+
+  // Click Publish
+  await agent.act('Click the "Publish Node" button');
+
+  // Check: User is redirected to chat (galaxy not implemented yet)
+  await agent.check('The page URL contains "/chat"');
+});
+
+test('[Unhappy Path] Publishing requires both title and body', async (agent) => {
+  await agent.act('Navigate to /editor/new');
+
+  // Try to publish without filling in the form
+  await agent.act('Click the "Publish Node" button');
+
+  // The form should prevent submission (Mantine form validation)
+  // The URL should still be /editor/new
+  await agent.check('The page URL contains "/editor/new"');
+});