feat: major platform expansion — Brain service, RSS reader, iOS app, AI assistants, Firefox extension

Brain Service: - Playwright stealth crawler replacing browserless (og:image, Readability, Reddit JSON API) - AI classification with tag definitions and folder assignment - YouTube video download via yt-dlp - Karakeep migration complete (96 items) - Taxonomy management (folders with icons/colors, tags) - Discovery shuffle, sort options, search (Meilisearch + pgvector) - Item tag/folder editing, card color accents RSS Reader Service: - Custom FastAPI reader replacing Miniflux - Feed management (add/delete/refresh), category support - Full article extraction via Readability - Background content fetching for new entries - Mark all read with confirmation - Infinite scroll, retention cleanup (30/60 day) - 17 feeds migrated from Miniflux iOS App (SwiftUI): - Native iOS 17+ app with @Observable architecture - Cookie-based auth, configurable gateway URL - Dashboard with custom background photo + frosted glass widgets - Full fitness module (today/templates/goals/food library) - AI assistant chat (fitness + brain, raw JSON state management) - 120fps ProMotion support AI Assistants (Gateway): - Unified dispatcher with fitness/brain domain detection - Fitness: natural language food logging, photo analysis, multi-item splitting - Brain: save/append/update/delete notes, search & answer, undo support - Madiha user gets fitness-only (brain disabled) Firefox Extension: - One-click save to Brain from any page - Login with platform credentials - Right-click context menu (save page/link/image) - Notes field for URL saves - Signed and published on AMO Other: - Reader bookmark button routes to Brain (was Karakeep) - Fitness food library with "Add" button + add-to-meal popup - Kindle send file size check (25MB SMTP2GO limit) - Atelier UI as default (useAtelierShell=true) - Mobile upload box in nav drawer Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-03 00:56:29 -05:00
parent af1765bd8e
commit 4592e35732
97 changed files with 11009 additions and 532 deletions
--- a/frontend-v2/src/routes/(app)/+layout.server.ts
+++ b/frontend-v2/src/routes/(app)/+layout.server.ts
@@ -6,7 +6,7 @@ const gatewayUrl = env.GATEWAY_URL || 'http://localhost:8100';

 export const load: LayoutServerLoad = async ({ cookies, url }) => {
 	const host = url.host.toLowerCase();
-	const useAtelierShell = host.includes(':4174') || host.startsWith('test.');
+	const useAtelierShell = true;
 	const session = cookies.get('platform_session');
 	if (!session) {
 		throw redirect(302, `/login?redirect=${encodeURIComponent(url.pathname)}`);
@@ -26,7 +26,7 @@ export const load: LayoutServerLoad = async ({ cookies, url }) => {
 				// Hiding reduces clutter for users who don't need certain apps day-to-day.
 				const allApps = ['tasks', 'trips', 'fitness', 'inventory', 'budget', 'reader', 'media', 'brain'];
 				const hiddenByUser: Record<string, string[]> = {
-					'madiha': ['inventory', 'reader'],
+					'madiha': ['inventory', 'reader', 'brain'],
 				};
 				const hidden = hiddenByUser[data.user.username] || [];
 				const visibleApps = allApps.filter(a => !hidden.includes(a));
--- a/frontend-v2/src/routes/(app)/+layout.svelte
+++ b/frontend-v2/src/routes/(app)/+layout.svelte
@@ -10,6 +10,7 @@
 	let assistantEntryDate = $state<string | null>(null);
 	const visibleApps = data?.visibleApps || ['trips', 'fitness', 'inventory', 'budget', 'reader', 'media'];
 	const userName = data?.user?.display_name || '';
+	const assistantBrainEnabled = data?.user?.username !== 'madiha';
 	const useAtelierShell = data?.useAtelierShell || false;

 	function openCommand() {
@@ -40,7 +41,7 @@
 	<AppShell onOpenCommand={openCommand} {visibleApps} {userName}>
 		{@render children()}
 	</AppShell>
-	<FitnessAssistantDrawer bind:open={commandOpen} onclose={closeCommand} entryDate={assistantEntryDate} />
+	<FitnessAssistantDrawer bind:open={commandOpen} onclose={closeCommand} entryDate={assistantEntryDate} allowBrain={assistantBrainEnabled} />
 {:else}
 	<div class="app">
 		<Navbar onOpenCommand={openCommand} {visibleApps} />
--- a/frontend-v2/src/routes/assistant/+server.ts
+++ b/frontend-v2/src/routes/assistant/+server.ts
@@ -0,0 +1,140 @@
+import { json } from '@sveltejs/kit';
+import { env } from '$env/dynamic/private';
+import type { RequestHandler } from './$types';
+
+type ChatRole = 'user' | 'assistant';
+
+type ChatMessage = {
+	role?: ChatRole;
+	content?: string;
+};
+
+type UnifiedState = {
+	activeDomain?: 'fitness' | 'brain';
+	fitnessState?: Record<string, unknown>;
+	brainState?: Record<string, unknown>;
+};
+
+function recentMessages(messages: unknown): Array<{ role: ChatRole; content: string }> {
+	if (!Array.isArray(messages)) return [];
+	return messages
+		.filter((message) => !!message && typeof message === 'object')
+		.map((message) => {
+			const item = message as ChatMessage;
+			return {
+				role: item.role === 'assistant' ? 'assistant' : 'user',
+				content: typeof item.content === 'string' ? item.content : ''
+			};
+		})
+		.filter((message) => message.content.trim())
+		.slice(-16);
+}
+
+function lastUserMessage(messages: Array<{ role: ChatRole; content: string }>): string {
+	return [...messages].reverse().find((message) => message.role === 'user')?.content?.trim() || '';
+}
+
+function isFitnessIntent(text: string): boolean {
+	return /\b(calories?|protein|carbs?|fat|sugar|fiber|breakfast|lunch|dinner|snack|meal|food|ate|eaten|log|track|entries|macros?)\b/i.test(text)
+		|| /\bfor (breakfast|lunch|dinner|snack)\b/i.test(text)
+		|| /\bhow many calories do i have left\b/i.test(text);
+}
+
+function isBrainIntent(text: string): boolean {
+	return /\b(note|notes|brain|remember|save this|save that|what do i have|what have i saved|find my|delete (?:that|this|note|item)|update (?:that|this|note)|from my notes)\b/i.test(text);
+}
+
+function detectDomain(
+	messages: Array<{ role: ChatRole; content: string }>,
+	state: UnifiedState,
+	imageDataUrl?: string | null
+): 'fitness' | 'brain' {
+	const text = lastUserMessage(messages);
+	if (imageDataUrl) return 'fitness';
+	if (!text) return state.activeDomain || 'brain';
+
+	const fitness = isFitnessIntent(text);
+	const brain = isBrainIntent(text);
+
+	if (fitness && !brain) return 'fitness';
+	if (brain && !fitness) return 'brain';
+
+	if (state.activeDomain === 'fitness' && !brain) return 'fitness';
+	if (state.activeDomain === 'brain' && !fitness) return 'brain';
+
+	return fitness ? 'fitness' : 'brain';
+}
+
+export const POST: RequestHandler = async ({ request, fetch, cookies }) => {
+	if (!cookies.get('platform_session')) {
+		return json({ error: 'Unauthorized' }, { status: 401 });
+	}
+
+	const { messages = [], state = {}, imageDataUrl = null, entryDate = null, action = 'chat', allowBrain = true } = await request
+		.json()
+		.catch(() => ({}));
+
+	let brainEnabled = !!allowBrain;
+	try {
+		const gatewayUrl = env.GATEWAY_URL || 'http://localhost:8100';
+		const session = cookies.get('platform_session');
+		if (session) {
+			const auth = await fetch(`${gatewayUrl}/api/auth/me`, {
+				headers: { Cookie: `platform_session=${session}` }
+			});
+			if (auth.ok) {
+				const data = await auth.json().catch(() => null);
+				if (data?.authenticated && data?.user?.username === 'madiha') {
+					brainEnabled = false;
+				}
+			}
+		}
+	} catch {
+		// keep requested allowBrain fallback
+	}
+
+	const chat = recentMessages(messages);
+	const unifiedState: UnifiedState = state && typeof state === 'object' ? state : {};
+	const domain = brainEnabled ? detectDomain(chat, unifiedState, imageDataUrl) : 'fitness';
+
+	const response = await fetch(domain === 'fitness' ? '/assistant/fitness' : '/assistant/brain', {
+		method: 'POST',
+		headers: { 'content-type': 'application/json' },
+		body: JSON.stringify(
+			domain === 'fitness'
+				? {
+						action,
+						messages,
+						draft: unifiedState.fitnessState && 'draft' in unifiedState.fitnessState ? unifiedState.fitnessState.draft : null,
+						drafts: unifiedState.fitnessState && 'drafts' in unifiedState.fitnessState ? unifiedState.fitnessState.drafts : [],
+						entryDate,
+						imageDataUrl
+					}
+				: {
+						messages,
+						state: unifiedState.brainState || {}
+					}
+		)
+	});
+
+	const body = await response.json().catch(() => ({}));
+	if (!response.ok) {
+		return json(body, { status: response.status });
+	}
+
+	return json({
+		...body,
+		domain,
+		state: {
+			activeDomain: domain,
+			fitnessState:
+				domain === 'fitness'
+					? {
+							draft: body?.draft ?? null,
+							drafts: Array.isArray(body?.drafts) ? body.drafts : []
+						}
+					: unifiedState.fitnessState || {},
+			brainState: domain === 'brain' ? body?.state || {} : unifiedState.brainState || {}
+		}
+	});
+};
--- a/frontend-v2/src/routes/assistant/brain/+server.ts
+++ b/frontend-v2/src/routes/assistant/brain/+server.ts
@@ -0,0 +1,799 @@
+import { env } from '$env/dynamic/private';
+import { json } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+
+type ChatRole = 'user' | 'assistant';
+
+type ChatMessage = {
+	role?: ChatRole;
+	content?: string;
+};
+
+type BrainItem = {
+	id: string;
+	type: string;
+	title?: string | null;
+	url?: string | null;
+	raw_content?: string | null;
+	extracted_text?: string | null;
+	folder?: string | null;
+	tags?: string[] | null;
+	summary?: string | null;
+	created_at?: string;
+};
+
+type BrainAddition = {
+	id: string;
+	item_id: string;
+	content: string;
+	created_at: string;
+};
+
+type AssistantState = {
+	lastMutation?: {
+		type: 'append' | 'create' | 'update';
+		itemId: string;
+		itemTitle: string;
+		additionId?: string;
+		content: string;
+		createdItemId?: string;
+		previousRawContent?: string;
+	};
+	pendingDelete?: {
+		itemId: string;
+		itemTitle: string;
+	};
+};
+
+type SourceLink = {
+	id: string;
+	title: string;
+	type: string;
+	href: string;
+};
+
+type SearchQueryDecision = {
+	queries?: string[];
+};
+
+function recentMessages(messages: unknown): Array<{ role: ChatRole; content: string }> {
+	if (!Array.isArray(messages)) return [];
+	return messages
+		.filter((m) => !!m && typeof m === 'object')
+		.map((m) => {
+			const message = m as ChatMessage;
+			return {
+				role: (message.role === 'assistant' ? 'assistant' : 'user') as ChatRole,
+				content: typeof message.content === 'string' ? message.content.slice(0, 4000) : ''
+			};
+		})
+		.filter((m) => m.content.trim())
+		.slice(-12);
+}
+
+function lastUserMessage(messages: Array<{ role: ChatRole; content: string }>): string {
+	return [...messages].reverse().find((message) => message.role === 'user')?.content?.trim() || '';
+}
+
+function toSource(item: BrainItem): SourceLink {
+	return {
+		id: item.id,
+		title: item.title || 'Untitled',
+		type: item.type,
+		href: `/brain?item=${item.id}`
+	};
+}
+
+function isConfirmation(text: string): boolean {
+	const clean = text.trim().toLowerCase();
+	return [
+		'yes',
+		'yes delete it',
+		'delete it',
+		'confirm',
+		'yes do it',
+		'do it',
+		'go ahead'
+	].includes(clean);
+}
+
+function isUndo(text: string): boolean {
+	return /^(undo|undo last change|undo that|revert that)$/i.test(text.trim());
+}
+
+function wantsNewNoteInstead(text: string): boolean {
+	return /create (?:a )?new note/i.test(text) || /make (?:that|it) a new note/i.test(text);
+}
+
+function moveTargetFromText(text: string): string | null {
+	const match = text.match(/(?:add|move)\s+(?:that|it)\s+to\s+(.+)$/i);
+	return match?.[1]?.trim() || null;
+}
+
+function wantsDelete(text: string): boolean {
+	return /\bdelete\b/i.test(text) && /\b(note|item|that)\b/i.test(text);
+}
+
+function isExplicitUpdateRequest(text: string): boolean {
+	return /\b(update|edit|change|replace|correct|set)\b/i.test(text);
+}
+
+function isListingIntent(text: string): boolean {
+	return /\b(what|which|show|list)\b/i.test(text)
+		&& /\b(do i have|have i saved|saved|notes|items|books?|pdfs?|links?|documents?|files?)\b/i.test(text);
+}
+
+function buildCandidateSummary(items: BrainItem[]): string {
+	if (!items.length) return 'No candidates found.';
+	return items
+		.map((item, index) => {
+			const snippet = (item.raw_content || item.extracted_text || item.summary || '')
+				.replace(/\s+/g, ' ')
+				.slice(0, 220);
+			return `${index + 1}. id=${item.id}
+title=${item.title || 'Untitled'}
+type=${item.type}
+folder=${item.folder || ''}
+tags=${(item.tags || []).join(', ')}
+snippet=${snippet}`;
+		})
+		.join('\n\n');
+}
+
+async function brainSearch(fetchFn: typeof fetch, q: string, limit = 5): Promise<BrainItem[]> {
+	const response = await fetchFn('/api/brain/search/hybrid', {
+		method: 'POST',
+		headers: { 'content-type': 'application/json' },
+		body: JSON.stringify({ q, limit })
+	});
+	if (!response.ok) return [];
+	const body = await response.json().catch(() => ({}));
+	return Array.isArray(body?.items) ? body.items : [];
+}
+
+function normalizeSearchSeed(text: string): string {
+	return text
+		.trim()
+		.replace(/^what\s+(books?|notes?|pdfs?|links?|documents?|files?)\s+do i have saved\s*/i, '$1 ')
+		.replace(/^show me\s+(all\s+)?(books?|notes?|pdfs?|links?|documents?|files?)\s*/i, '$2 ')
+		.replace(/^list\s+(my\s+)?(books?|notes?|pdfs?|links?|documents?|files?)\s*/i, '$2 ')
+		.replace(/^add note\s+/i, '')
+		.replace(/^add\s+/i, '')
+		.replace(/^save\s+(?:this|that)\s+/i, '')
+		.replace(/^what do i have about\s+/i, '')
+		.replace(/^what have i saved about\s+/i, '')
+		.replace(/^find\s+/i, '')
+		.replace(/^search for\s+/i, '')
+		.replace(/^answer\s+/i, '')
+		.trim();
+}
+
+async function deriveSearchQueries(
+	messages: Array<{ role: ChatRole; content: string }>,
+	userText: string
+): Promise<string[]> {
+	const normalized = normalizeSearchSeed(userText);
+	const fallback = [normalized || userText.trim()].filter(Boolean);
+	if (!env.OPENAI_API_KEY) return fallback;
+
+	const systemPrompt = `You extract concise retrieval queries for a personal knowledge base.
+
+Return ONLY JSON:
+{
+  "queries": ["query one", "query two"]
+}
+
+Rules:
+- Return 1 to 3 short search queries.
+- Focus on the underlying topic, not chat filler.
+- For "what do I have about X", include just X.
+- For advice/tips, you may infer a likely broader topic if strongly implied.
+- Keep each query short, usually 1 to 5 words.
+- Do not include punctuation-heavy sentences.
+- Do not include explanatory text.`;
+
+	const response = await fetch('https://api.openai.com/v1/chat/completions', {
+		method: 'POST',
+		headers: {
+			'content-type': 'application/json',
+			authorization: `Bearer ${env.OPENAI_API_KEY}`
+		},
+		body: JSON.stringify({
+			model: env.OPENAI_MODEL || 'gpt-5.2',
+			response_format: { type: 'json_object' },
+			temperature: 0.1,
+			max_completion_tokens: 200,
+			messages: [
+				{ role: 'system', content: systemPrompt },
+				...messages.slice(-6),
+				{ role: 'user', content: `Search intent: ${userText}` }
+			]
+		})
+	});
+
+	if (!response.ok) return fallback;
+	const raw = await response.json().catch(() => null);
+	const content = raw?.choices?.[0]?.message?.content;
+	if (typeof content !== 'string') return fallback;
+
+	try {
+		const parsed = JSON.parse(content) as SearchQueryDecision;
+		const queries = Array.isArray(parsed.queries)
+			? parsed.queries.map((query) => String(query || '').trim()).filter(Boolean).slice(0, 3)
+			: [];
+		return queries.length ? queries : fallback;
+	} catch {
+		return fallback;
+	}
+}
+
+async function collectCandidates(
+	fetchFn: typeof fetch,
+	messages: Array<{ role: ChatRole; content: string }>,
+	userText: string,
+	limit = 8
+): Promise<BrainItem[]> {
+	const queries = await deriveSearchQueries(messages, userText);
+	const merged = new Map<string, BrainItem>();
+
+	for (const query of queries) {
+		const items = await brainSearch(fetchFn, query, limit);
+		for (const item of items) {
+			if (!merged.has(item.id)) merged.set(item.id, item);
+		}
+	}
+
+	if (!merged.size) {
+		for (const item of await brainSearch(fetchFn, userText, limit)) {
+			if (!merged.has(item.id)) merged.set(item.id, item);
+		}
+	}
+
+	return [...merged.values()].slice(0, limit);
+}
+
+async function createBrainNote(fetchFn: typeof fetch, content: string, title?: string) {
+	const response = await fetchFn('/api/brain/items', {
+		method: 'POST',
+		headers: { 'content-type': 'application/json' },
+		body: JSON.stringify({
+			type: 'note',
+			raw_content: content,
+			title: title?.trim() || undefined
+		})
+	});
+	return {
+		ok: response.ok,
+		status: response.status,
+		body: await response.json().catch(() => ({}))
+	};
+}
+
+async function updateBrainItem(fetchFn: typeof fetch, itemId: string, body: { raw_content?: string; title?: string }) {
+	const response = await fetchFn(`/api/brain/items/${itemId}`, {
+		method: 'PATCH',
+		headers: { 'content-type': 'application/json' },
+		body: JSON.stringify(body)
+	});
+	return {
+		ok: response.ok,
+		status: response.status,
+		body: await response.json().catch(() => ({}))
+	};
+}
+
+async function appendToItem(fetchFn: typeof fetch, itemId: string, content: string) {
+	const response = await fetchFn(`/api/brain/items/${itemId}/additions`, {
+		method: 'POST',
+		headers: { 'content-type': 'application/json' },
+		body: JSON.stringify({ content, source: 'assistant', kind: 'append' })
+	});
+	return {
+		ok: response.ok,
+		status: response.status,
+		body: await response.json().catch(() => ({}))
+	};
+}
+
+async function deleteAddition(fetchFn: typeof fetch, itemId: string, additionId: string) {
+	const response = await fetchFn(`/api/brain/items/${itemId}/additions/${additionId}`, {
+		method: 'DELETE'
+	});
+	return response.ok;
+}
+
+async function deleteItem(fetchFn: typeof fetch, itemId: string) {
+	const response = await fetchFn(`/api/brain/items/${itemId}`, { method: 'DELETE' });
+	return response.ok;
+}
+
+async function getItem(fetchFn: typeof fetch, itemId: string): Promise<BrainItem | null> {
+	const response = await fetchFn(`/api/brain/items/${itemId}`);
+	if (!response.ok) return null;
+	return response.json().catch(() => null);
+}
+
+async function decideAction(
+	messages: Array<{ role: ChatRole; content: string }>,
+	candidates: BrainItem[],
+	state: AssistantState,
+	listingIntent = false
+) {
+	const systemPrompt = `You are the Brain assistant inside a personal app.
+
+You help the user save notes naturally, append thoughts to existing items, answer questions from saved notes, and choose whether to create a new note.
+
+Return ONLY JSON with this shape:
+{
+  "action": "append_existing" | "create_new_note" | "update_existing" | "answer" | "list_items" | "delete_target",
+  "reply": "short reply preview",
+  "target_item_id": "optional item id",
+  "formatted_content": "text to append or create",
+  "create_title": "short AI-generated title when creating a new note",
+  "answer": "short answer when action=answer",
+  "source_item_ids": ["id1", "id2"],
+  "match_confidence": "high" | "low"
+}
+
+Rules:
+- Use existing items only when the topical match is strong.
+- If the match is weak or ambiguous, create a new note.
+- The user prefers speed: do not ask which note to use.
+- If the user explicitly says update, change, edit, replace, set, or correct, prefer update_existing when one strong existing note clearly matches.
+- If the user is asking to list what they have saved, prefer list_items instead of answer.
+- For short tips/advice, format as bullets when natural.
+- Only fix spelling and grammar. Do not rewrite the meaning.
+- For questions, answer briefly and cite up to 3 source ids.
+- For list_items, return a concise list-style reply and cite up to 12 source ids.
+- For delete requests, choose the most likely target and set action=delete_target.
+- Never choose append_existing unless target_item_id is one of the candidate ids.
+- Never choose update_existing unless target_item_id is one of the candidate ids.
+- If all candidates are weak, set action=create_new_note and match_confidence=low.
+- The current assistant state is only for context:
+${JSON.stringify(state, null, 2)}
+- listing_intent=${listingIntent}
+`;
+
+	const response = await fetch('https://api.openai.com/v1/chat/completions', {
+		method: 'POST',
+		headers: {
+			'content-type': 'application/json',
+			authorization: `Bearer ${env.OPENAI_API_KEY}`
+		},
+		body: JSON.stringify({
+			model: env.OPENAI_MODEL || 'gpt-5.2',
+			response_format: { type: 'json_object' },
+			temperature: 0.2,
+			max_completion_tokens: 1100,
+			messages: [
+				{ role: 'system', content: systemPrompt },
+				...messages,
+				{
+					role: 'user',
+					content: `Candidate items:\n${buildCandidateSummary(candidates)}`
+				}
+			]
+		})
+	});
+
+	if (!response.ok) {
+		throw new Error(await response.text());
+	}
+
+	const raw = await response.json();
+	const content = raw?.choices?.[0]?.message?.content;
+	if (typeof content !== 'string') {
+		throw new Error('Assistant response was empty.');
+	}
+
+	return JSON.parse(content) as {
+		action?: 'append_existing' | 'create_new_note' | 'update_existing' | 'answer' | 'list_items' | 'delete_target';
+		reply?: string;
+		target_item_id?: string;
+		formatted_content?: string;
+		create_title?: string;
+		answer?: string;
+		source_item_ids?: string[];
+		match_confidence?: 'high' | 'low';
+	};
+}
+
+async function rewriteExistingItemContent(
+	messages: Array<{ role: ChatRole; content: string }>,
+	target: BrainItem,
+	userInstruction: string
+): Promise<string> {
+	const existing = (target.raw_content || target.extracted_text || '').trim();
+	if (!existing) {
+		throw new Error('Target item has no editable content.');
+	}
+
+	const systemPrompt = `You edit an existing personal note in place.
+
+Return ONLY JSON:
+{
+  "updated_content": "full updated note body"
+}
+
+Rules:
+- Apply the user's requested update to the existing note.
+- Preserve the note's structure and wording as much as possible.
+- Make the smallest correct change needed.
+- Do not append a new line when the user clearly wants an existing value updated.
+- Only fix spelling and grammar where needed for the changed text.
+- Return the full updated note body, not a diff.`;
+
+	const response = await fetch('https://api.openai.com/v1/chat/completions', {
+		method: 'POST',
+		headers: {
+			'content-type': 'application/json',
+			authorization: `Bearer ${env.OPENAI_API_KEY}`
+		},
+		body: JSON.stringify({
+			model: env.OPENAI_MODEL || 'gpt-5.2',
+			response_format: { type: 'json_object' },
+			temperature: 0.1,
+			max_completion_tokens: 900,
+			messages: [
+				{ role: 'system', content: systemPrompt },
+				...messages.slice(-8),
+				{
+					role: 'user',
+					content: `Target title: ${target.title || 'Untitled'}\n\nExisting note:\n${existing}\n\nInstruction: ${userInstruction}`
+				}
+			]
+		})
+	});
+
+	if (!response.ok) {
+		throw new Error(await response.text());
+	}
+
+	const raw = await response.json();
+	const content = raw?.choices?.[0]?.message?.content;
+	if (typeof content !== 'string') {
+		throw new Error('Update response was empty.');
+	}
+	const parsed = JSON.parse(content) as { updated_content?: string };
+	const updated = parsed.updated_content?.trim();
+	if (!updated) {
+		throw new Error('Updated content was empty.');
+	}
+	return updated;
+}
+
+function sourceLinksFromIds(items: BrainItem[], ids: string[] | undefined): SourceLink[] {
+	if (!Array.isArray(ids) || !ids.length) return [];
+	const map = new Map(items.map((item) => [item.id, item]));
+	return ids.map((id) => map.get(id)).filter(Boolean).map((item) => toSource(item as BrainItem));
+}
+
+export const POST: RequestHandler = async ({ request, fetch, cookies }) => {
+	if (!cookies.get('platform_session')) {
+		return json({ error: 'Unauthorized' }, { status: 401 });
+	}
+	if (!env.OPENAI_API_KEY) {
+		return json({ error: 'Assistant is not configured.' }, { status: 500 });
+	}
+
+	const { messages = [], state = {} } = await request.json().catch(() => ({}));
+	const chat = recentMessages(messages);
+	const userText = lastUserMessage(chat);
+	const currentState: AssistantState = state && typeof state === 'object' ? state : {};
+
+	if (!userText) {
+		return json({
+			reply: 'Tell me what to save, find, answer, or delete.',
+			state: currentState,
+			sources: []
+		});
+	}
+
+	if (currentState.pendingDelete && isConfirmation(userText)) {
+		const target = currentState.pendingDelete;
+		const ok = await deleteItem(fetch, target.itemId);
+		if (!ok) {
+			return json({ reply: `I couldn't delete "${target.itemTitle}" yet.`, state: currentState, sources: [] }, { status: 500 });
+		}
+		return json({
+			reply: `Deleted "${target.itemTitle}".`,
+			state: {},
+			sources: []
+		});
+	}
+
+	if (currentState.lastMutation && isUndo(userText)) {
+		if (currentState.lastMutation.type === 'append' && currentState.lastMutation.additionId) {
+			const ok = await deleteAddition(fetch, currentState.lastMutation.itemId, currentState.lastMutation.additionId);
+			return json({
+				reply: ok ? `Undid the change in "${currentState.lastMutation.itemTitle}".` : 'I could not undo that change yet.',
+				state: ok ? {} : currentState,
+				sources: ok ? [{ id: currentState.lastMutation.itemId, title: currentState.lastMutation.itemTitle, type: 'note', href: `/brain?item=${currentState.lastMutation.itemId}` }] : []
+			});
+		}
+		if (currentState.lastMutation.type === 'create' && currentState.lastMutation.createdItemId) {
+			const ok = await deleteItem(fetch, currentState.lastMutation.createdItemId);
+			return json({
+				reply: ok ? `Removed "${currentState.lastMutation.itemTitle}".` : 'I could not undo that note creation yet.',
+				state: ok ? {} : currentState,
+				sources: []
+			});
+		}
+		if (currentState.lastMutation.type === 'update' && currentState.lastMutation.previousRawContent !== undefined) {
+			const restored = await updateBrainItem(fetch, currentState.lastMutation.itemId, {
+				raw_content: currentState.lastMutation.previousRawContent
+			});
+			return json({
+				reply: restored.ok ? `Undid the update in "${currentState.lastMutation.itemTitle}".` : 'I could not undo that update yet.',
+				state: restored.ok ? {} : currentState,
+				sources: restored.ok ? [{ id: currentState.lastMutation.itemId, title: currentState.lastMutation.itemTitle, type: 'note', href: `/brain?item=${currentState.lastMutation.itemId}` }] : []
+			});
+		}
+	}
+
+	if (currentState.lastMutation && wantsNewNoteInstead(userText)) {
+		const content = currentState.lastMutation.content;
+		if (currentState.lastMutation.type === 'append' && currentState.lastMutation.additionId) {
+			await deleteAddition(fetch, currentState.lastMutation.itemId, currentState.lastMutation.additionId);
+		}
+		const titleDecision = await decideAction(
+			[{ role: 'user', content: `Create a concise title for this note:\n${content}` }],
+			[],
+			currentState
+		).catch(() => ({ create_title: 'New Note' }));
+		const created = await createBrainNote(fetch, content, titleDecision.create_title);
+		if (!created.ok) {
+			return json({ reply: 'I could not create the new note yet.', state: currentState, sources: [] }, { status: 500 });
+		}
+		const createdItem = created.body as BrainItem;
+		return json({
+			reply: `Created "${createdItem.title || titleDecision.create_title || 'New note'}".`,
+			state: {
+				lastMutation: {
+					type: 'create',
+					itemId: createdItem.id,
+					createdItemId: createdItem.id,
+					itemTitle: createdItem.title || titleDecision.create_title || 'New note',
+					content
+				}
+			},
+			sources: [toSource(createdItem)]
+		});
+	}
+
+	const retarget = currentState.lastMutation ? moveTargetFromText(userText) : null;
+	if (currentState.lastMutation && retarget) {
+		if (currentState.lastMutation.type === 'append' && currentState.lastMutation.additionId) {
+			await deleteAddition(fetch, currentState.lastMutation.itemId, currentState.lastMutation.additionId);
+		} else if (currentState.lastMutation.type === 'create' && currentState.lastMutation.createdItemId) {
+			await deleteItem(fetch, currentState.lastMutation.createdItemId);
+		}
+
+		const candidates = await collectCandidates(fetch, chat, retarget, 8);
+		const target = candidates[0];
+		if (!target) {
+			const created = await createBrainNote(fetch, currentState.lastMutation.content, retarget);
+			if (!created.ok) {
+				return json({ reply: 'I could not move that into a new note yet.', state: currentState, sources: [] }, { status: 500 });
+			}
+			const createdItem = created.body as BrainItem;
+			return json({
+				reply: `Created "${createdItem.title || retarget}".`,
+				state: {
+					lastMutation: {
+						type: 'create',
+						itemId: createdItem.id,
+						createdItemId: createdItem.id,
+						itemTitle: createdItem.title || retarget,
+						content: currentState.lastMutation.content
+					}
+				},
+				sources: [toSource(createdItem)]
+			});
+		}
+
+		const appended = await appendToItem(fetch, target.id, currentState.lastMutation.content);
+		if (!appended.ok) {
+			return json({ reply: `I couldn't move that to "${target.title || 'that item'}" yet.`, state: currentState, sources: [] }, { status: 500 });
+		}
+		return json({
+			reply: `Moved it to "${target.title || 'Untitled'}".`,
+			state: {
+				lastMutation: {
+					type: 'append',
+					itemId: target.id,
+					itemTitle: target.title || 'Untitled',
+					additionId: appended.body?.id,
+					content: currentState.lastMutation.content
+				}
+			},
+			sources: [toSource(target)]
+		});
+	}
+
+	const listingIntent = isListingIntent(userText);
+	const candidates = await collectCandidates(fetch, chat, userText, listingIntent ? 24 : 8);
+
+	if (isExplicitUpdateRequest(userText) && candidates[0] && (candidates[0].raw_content || candidates[0].extracted_text)) {
+		const target = candidates[0];
+		try {
+			const updatedContent = await rewriteExistingItemContent(chat, target, userText);
+			const updated = await updateBrainItem(fetch, target.id, { raw_content: updatedContent });
+			if (!updated.ok) {
+				return json({ reply: `I couldn't update "${target.title || 'Untitled'}" yet.`, state: currentState, sources: [] }, { status: 500 });
+			}
+			return json({
+				reply: `Updated "${target.title || 'Untitled'}".`,
+				state: {
+					lastMutation: {
+						type: 'update',
+						itemId: target.id,
+						itemTitle: target.title || 'Untitled',
+						content: updatedContent,
+						previousRawContent: target.raw_content || target.extracted_text || ''
+					}
+				},
+				sources: [toSource(target)]
+			});
+		} catch (error) {
+			return json(
+				{
+					reply: `I couldn't update "${target.title || 'Untitled'}" yet.`,
+					state: currentState,
+					sources: [toSource(target)],
+					error: error instanceof Error ? error.message : 'Unknown error'
+				},
+				{ status: 500 }
+			);
+		}
+	}
+
+	if (wantsDelete(userText) && !currentState.pendingDelete) {
+		const target = candidates[0];
+		if (!target) {
+			return json({ reply: "I couldn't find a note to delete.", state: currentState, sources: [] });
+		}
+		return json({
+			reply: `Delete "${target.title || 'Untitled'}"?`,
+			state: {
+				...currentState,
+				pendingDelete: {
+					itemId: target.id,
+					itemTitle: target.title || 'Untitled'
+				}
+			},
+			sources: [toSource(target)]
+		});
+	}
+
+	let decision;
+	try {
+		decision = await decideAction(chat, candidates, currentState, listingIntent);
+	} catch (error) {
+		return json(
+			{
+				reply: 'The Brain assistant did not respond cleanly.',
+				state: currentState,
+				sources: [],
+				error: error instanceof Error ? error.message : 'Unknown error'
+			},
+			{ status: 500 }
+		);
+	}
+
+	if (decision.action === 'answer') {
+		return json({
+			reply: decision.answer || decision.reply || 'I found a few relevant notes.',
+			state: currentState,
+			sources: sourceLinksFromIds(candidates, decision.source_item_ids)
+		});
+	}
+
+	if (decision.action === 'list_items') {
+		return json({
+			reply: decision.answer || decision.reply || 'Here are the matching items I found.',
+			state: currentState,
+			sources: sourceLinksFromIds(candidates, decision.source_item_ids)
+		});
+	}
+
+	if (decision.action === 'delete_target' && decision.target_item_id) {
+		const target = candidates.find((item) => item.id === decision.target_item_id) || (await getItem(fetch, decision.target_item_id));
+		if (!target) {
+			return json({ reply: "I couldn't find that note to delete.", state: currentState, sources: [] });
+		}
+		return json({
+			reply: `Delete "${target.title || 'Untitled'}"?`,
+			state: {
+				...currentState,
+				pendingDelete: {
+					itemId: target.id,
+					itemTitle: target.title || 'Untitled'
+				}
+			},
+			sources: [toSource(target)]
+		});
+	}
+
+	if (decision.action === 'update_existing' && decision.target_item_id && decision.match_confidence === 'high') {
+		const target = candidates.find((item) => item.id === decision.target_item_id) || (await getItem(fetch, decision.target_item_id));
+		if (target && (target.raw_content || target.extracted_text)) {
+			try {
+				const updatedContent = await rewriteExistingItemContent(chat, target, userText);
+				const updated = await updateBrainItem(fetch, target.id, { raw_content: updatedContent });
+				if (!updated.ok) {
+					return json({ reply: `I couldn't update "${target.title || 'Untitled'}" yet.`, state: currentState, sources: [] }, { status: 500 });
+				}
+				return json({
+					reply: `Updated "${target.title || 'Untitled'}".`,
+					state: {
+						lastMutation: {
+							type: 'update',
+							itemId: target.id,
+							itemTitle: target.title || 'Untitled',
+							content: updatedContent,
+							previousRawContent: target.raw_content || target.extracted_text || ''
+						}
+					},
+					sources: [toSource(target)]
+				});
+			} catch (error) {
+				return json(
+					{
+						reply: `I couldn't update "${target.title || 'Untitled'}" yet.`,
+						state: currentState,
+						sources: [toSource(target)],
+						error: error instanceof Error ? error.message : 'Unknown error'
+					},
+					{ status: 500 }
+				);
+			}
+		}
+	}
+
+	const content = decision.formatted_content?.trim() || userText;
+
+	if (decision.action === 'append_existing' && decision.target_item_id && decision.match_confidence === 'high') {
+		const target = candidates.find((item) => item.id === decision.target_item_id) || (await getItem(fetch, decision.target_item_id));
+		if (!target) {
+			// fall through to create below
+		} else {
+			const appended = await appendToItem(fetch, target.id, content);
+			if (!appended.ok) {
+				return json({ reply: `I couldn't add that to "${target.title || 'Untitled'}" yet.`, state: currentState, sources: [] }, { status: 500 });
+			}
+			return json({
+				reply: `Added to "${target.title || 'Untitled'}".`,
+				state: {
+					lastMutation: {
+						type: 'append',
+						itemId: target.id,
+						itemTitle: target.title || 'Untitled',
+						additionId: appended.body?.id,
+						content
+					}
+				},
+				sources: [toSource(target)]
+			});
+		}
+	}
+
+	const created = await createBrainNote(fetch, content, decision.create_title);
+	if (!created.ok) {
+		return json({ reply: 'I could not create the note yet.', state: currentState, sources: [] }, { status: 500 });
+	}
+	const createdItem = created.body as BrainItem;
+	return json({
+		reply: `Created "${createdItem.title || decision.create_title || 'New note'}".`,
+		state: {
+			lastMutation: {
+				type: 'create',
+				itemId: createdItem.id,
+				createdItemId: createdItem.id,
+				itemTitle: createdItem.title || decision.create_title || 'New note',
+				content
+			}
+		},
+		sources: [toSource(createdItem)]
+	});
+};