Build apps

AI calls

crow.ai lets a page call an AI model without putting a key in the page. By default it uses Crow Nest AI: nothing to set up, no key to find. You can also bring your own key.

#Crow Nest AI

An app that turns AI on in crow.json works as soon as it's published. Crow Nest makes the call for you and adds what it used to your monthly bill, at cost plus 15%. The first $1 each month is included.

• Who can use it. A personal workspace needs a paid plan with a card (Flat or Pay as you go). An organization or company needs billing set up. Without that, calls answer ai_needs_billing and the app's owner is told to add a card.
• The cap. Each workspace has a monthly cap on AI spend, $25 unless you change it (Settings, or the organization's Billing page; 0 turns Crow Nest AI off). You get an email at 80% and at 100%. At 100%, calls answer ai_cap_reached until next month or a higher cap.
• Models. anthropic/claude-haiku-5.5 (fast, the default), anthropic/claude-sonnet-5.5 (balanced) and anthropic/claude-opus-5.5 (strongest). The app's AI page lists them too. Pass one of their ids as model; any other id answers a 400 that names the allowed ones.
• Organizations. Admins can switch Crow Nest AI off for everyone in the Policy page.
• Privacy. Prompts and replies go to the model's maker and are never stored by Crow Nest. We keep counts and costs only.

Apps published before Crow Nest AI that had AI on but no key switch to it on their next publish, and the publish reply says so.

#Bring your own key

If you'd rather use your own account, add a key. Then the provider bills that key and Crow Nest adds nothing.

#1. Add a key

Ask your AI to add an AI key. It uses the ai_key tool, which asks you for the key privately; never paste a key into the chat. You can also add one in the dashboard under Settings, AI keys. Crow Nest works out the provider from the key: Anthropic, OpenAI, Google, or an OpenAI-compatible service.

Keys are stored encrypted on the server and never shown again.

#2. Choose which key the app uses

Ask your AI to set it (the tool_ai tool) or use the app's AI page in the dashboard: crow (Crow Nest AI, the default), company, mine (your personal key), tool (a key saved on the app) or none.

#3. Turn it on in crow.json

{ "ai": { "who": "viewers", "perViewerPerMinute": 10, "dailyLimit": 500 } }

who is owner, viewers, or public (public apps only). perViewerPerMinute and dailyLimit cap use.

#4. Call it

const r = await crow.ai.chat({
  messages: [{ role: "user", content: "Summarize this: ..." }],
  system: "You are concise.",      // optional
  model: "claude-sonnet-5-5",      // optional; the key's default model otherwise
  maxTokens: 1024,                 // optional, at most 8192
});
r.text;    // the answer
r.usage;   // { inputTokens, outputTokens }

try {
  for await (const chunk of crow.ai.stream({ messages })) out.textContent += chunk;   // streamed text
} catch (e) {
  // e.code "stream_interrupted": the answer was cut off part way. Keep what arrived and offer a Retry.
}

#Errors

ai_not_enabled (no ai in crow.json), ai_no_key (no key for this app), ai_key_needs_ack (the owner hasn't accepted the cost warning), ai_needs_billing (Crow Nest AI without a card or billing), ai_cap_reached (the monthly cap), rate_limited.

A stream can also stop part way: stream_interrupted when the connection drops, or ai_provider_error when the model's provider cuts the answer off. The pieces that arrived stay; the loop throws instead of ending, so an app can tell a cut-off answer from a finished one.

#Seeing costs

Settings and the organization's Billing page show what Crow Nest AI cost this month, what's included and the cap. The app's page in the dashboard shows AI calls, tokens and estimated cost per key. Company admins see the same for company keys.

#From server code

Server code calls the same models with env.CROW.ai.chat(...), under the same key setting and limits. See Server code.