Summary

createPluginHandler() in src/infra/outbound/deliver.ts requires both sendText AND sendMedia at runtime:

if (!outbound?.sendText || !outbound?.sendMedia) {
  return null;
}

But the ChannelOutboundAdapter type in plugin-sdk/channels/plugins/types.adapters.d.ts marks sendMedia as optional:

export type ChannelOutboundAdapter = {
    // ...
    sendText?: (ctx: ChannelOutboundContext) => Promise<OutboundDeliveryResult>;
    sendMedia?: (ctx: ChannelOutboundContext) => Promise<OutboundDeliveryResult>;  // optional
};

The plugin documentation (docs/tools/plugin.md) also shows a minimal channel plugin example with only sendText and no sendMedia.

Impact

Any channel plugin that only implements sendText (text-only channels) is completely broken for outbound. When sendMedia is absent, createPluginHandler() returns null, and the caller throws:

Error: Outbound not configured for channel: <id>

This blocks ALL outbound for that channel — including pure text sends — even though the channel correctly implements sendText.

Use Case

Text-only channels where media doesn't apply:

• Inter-agent messaging over database tables
• IRC bridges
• Webhook-only notification channels
• Any custom channel where messages are text records, not rich media

Expected Behavior

A channel plugin implementing only sendText should be able to send text messages. When media delivery is attempted on a text-only channel, it should gracefully degrade (e.g., send the caption text, drop the media URL).

Suggested Fix

Only require sendText in the guard. When sendMedia is absent, synthesize a fallback that sends caption text via sendText:

if (!outbound?.sendText) {
  return null;
}

This aligns the runtime behavior with the type definition and the documented minimal channel plugin pattern.