Prompts and attachments

The bridge turns an incoming channel event into an agent prompt, loading attachment bytes only during prompt preparation. See Channel agent for service setup and the full option reference.

Multimodal prompts

The default prompt stays a plain string for text-only messages and becomes multimodal content when attachments are present. The adapter loads authenticated bytes only during prompt preparation, bounded by the multimodal policy.

Defaults: 10 attachments, 20 MiB per file, 50 MiB total, and 2 concurrent loads.

const service = createChannelAgent({
  channel,
  agent,
  multimodal: {
    maximumAttachments: 5,
    maximumAttachmentBytes: 10 * 1024 * 1024,
    maximumTotalAttachmentBytes: 25 * 1024 * 1024,
    attachmentConcurrency: 2,
  },
})

Use channelMessagePrompt() inside a custom createPrompt so custom instructions do not silently discard attachments:

import { channelMessagePrompt } from '@anvia/channel-agent'

const service = createChannelAgent({
  channel,
  agent,
  async createPrompt(request) {
    return channelMessagePrompt({
      channel: request.context.channel,
      event: request.event,
      signal: request.context.abortSignal,
      maximumAttachments: 3,
    })
  },
})

Set multimodal: false to reject attachment-bearing input before the model runs.

Continue with

• Filter events and scope memory — decide which events reach the agent.
• Streaming and delivery — render the outcome back to the channel.