ADR-0005 — Channel port with one adapter

Status: accepted · Date: 2026-09-14

Context

The agent should not be permanently wedded to ManyChat, but building adapters for platforms nobody has asked for is speculative work, and a port validated by a single implementation is really only a guess at the right seam.

Decision

Define a narrow ChannelAdapter port — parse, render, push — and ship exactly one implementation (ManyChat). Channel differences are data, carried in a ChannelCapabilities value, not branches in the renderer.

Consequences

• The WhatsApp constraints (no quick replies, 3 buttons) are enforced by a capability object and covered by tests, rather than remembered by the author.
• Adding Telegram later is a new adapter and a capability row, not a refactor.
• The port may need adjusting when a second adapter arrives. Accepted: one adapter's worth of evidence is cheaper to correct than three adapters'.
• A local simulator implements the same contract, so the agent is fully testable with no ManyChat account — which matters because Dev Tools require a paid plan.