Using Groq llama-3.3-70b for Tag Suggestions

Why Groq?

Tag suggestion is a speed-first task:

Users expect tag candidates to appear while they're still typing
Target: 1–3 second response time
Accuracy: "good enough" beats "perfect"

Claude Sonnet is excellent — but overkill for tagging.
Groq's llama-3.3-70b offers a free tier + 400 tokens/sec throughput that's exactly right here.

AI Routing Reference (this project's decision matrix)

Task	AI Choice	Reason
Tag suggestions	Groq llama-3.3-70b	Speed-first, free tier
Long-form summaries	Claude Haiku	Cost-effective, consistent quality
Design decisions	Claude Sonnet	Accuracy-first
Competitor research	NotebookLM	Free, handles large document sets
Image generation	Nano Banana API	Gemini Imagen integration

Task-based routing beats "Claude for everything" — better cost and latency at the same time.

Supabase Edge Function Implementation

// ai-hub/index.ts (action: "tags.suggest")
case "tags.suggest": {
  const { text } = body;

  const response = await fetch("https://api.groq.com/openai/v1/chat/completions", {
    method: "POST",
    headers: {
      "Authorization": `Bearer ${Deno.env.get("GROQ_API_KEY")}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      model: "llama-3.3-70b-versatile",
      messages: [
        {
          role: "system",
          content: "Suggest 3–5 tags, comma-separated. In Japanese.",
        },
        { role: "user", content: text.slice(0, 500) }, // cost control
      ],
      max_tokens: 50,
      temperature: 0.3,
    }),
  });

  const data = await response.json();
  const tags = data.choices[0].message.content
    .split(",")
    .map((t: string) => t.trim())
    .filter((t: string) => t.length > 0);

  return new Response(JSON.stringify({ tags }), {
    headers: { "Content-Type": "application/json" },
  });
}

Flutter Side: Debounce for Real-Time Suggestions

// note_editor_page.dart
Timer? _tagDebounce;

void _onNoteChanged(String text) {
  _tagDebounce?.cancel();
  _tagDebounce = Timer(const Duration(milliseconds: 800), () {
    if (text.length > 50) {
      _fetchTagSuggestions(text);
    }
  });
}

Future<void> _fetchTagSuggestions(String text) async {
  final response = await Supabase.instance.client.functions.invoke(
    'ai-hub',
    body: {'action': 'tags.suggest', 'text': text},
  );

  final tags = List<String>.from(response.data['tags'] ?? []);
  if (mounted) setState(() => _suggestedTags = tags);
}

800ms debounce means "don't call while the user is still typing" — API cost stays minimal.

Groq Constraints and Mitigations

Constraint	Mitigation
Free tier: 30 req/min	800ms debounce + rate limit guard
Context window: 8K tokens	Slice input to 500 chars
Japanese quality: slightly lower	Force Japanese via system prompt

When Groq returns a rate-limit error, fall back to Claude Haiku:

if (!response.ok) {
  // Groq rate-limited → fall back to Claude Haiku
  return suggestTagsWithClaude(text);
}

Key Takeaway

For speed-first, accuracy-optional tasks like tag suggestions, Groq llama-3.3-70b is the right tool.

Before reaching for Claude Sonnet on a new feature, ask: does this task actually need Sonnet-level quality? That question alone cuts AI infrastructure costs significantly.

Building in public: https://my-web-app-b67f4.web.app/