Chat title

chatTitle() adds title generation for chat-style Agent output. It can use a model, a custom executor, or a local heuristic, then streams or returns the title as output metadata.

Installation

Import the Capability factory from -hub/agent/capabilities and add it to defineAgent({ capabilities }). Use the configuration example below as the starting point, then tighten modes, policies, stores, and providers for the Agent boundary.

What it adds

The Capability reads the first user message, generates a short title, provides it as a finish extension, and injects title data into compatible streams. It can filter by Agent Trigger id when title generation should run only for selected triggers.

Configuration

Attach chatTitle() beside chat() for chat surfaces. When no model is available to the Capability, ViteHub falls back to a short heuristic title.

import { defineAgent } from '@vite-hub/agent'
import { chat, chatTitle } from '@vite-hub/agent/capabilities'

export default defineAgent({
  driver: { model },
  capabilities: [
    chat(),
    chatTitle(),
  ],
})

Runtime behavior

chatTitle() runs in the output phase. It wraps compatible async streams or UI message streams so the title can arrive alongside the response, and it provides { title } in the finish extension.

The Capability avoids wrapping the same result twice.

Requirements

chatTitle() needs message-shaped input with at least one user message. A model, custom executor, or heuristic path must be available.

Use a custom template, variables, or executor when the title must include product-specific context.

Driver support

Inspect and verify

Send one chat message and inspect the stream for chat title data. The finish extension should include { title } when title generation succeeds.

Test a vague first message and confirm the fallback title is used instead of an empty string.

Options

Reference

• chat()
• chatSummary()
• Source: packages/agent/src/capabilities/chat-title.ts