channel_reply

Send a message from the AI agent to the developer's browser overlay as a toast. Part of Channel Mode — it lets the agent talk back to the human in the browser without a PTY indicator.

Registered only when channel mode is enabled with reply-tool true (the default once channel.enabled true is set).

Synopsis

channel_reply {content: "Build succeeded, opening preview..."}
channel_reply {content: "Which layout?", title: "Choose", severity: "warning", proxy_id: "dev"}

Parameters

Parameter	Type	Required	Description
content	string	Yes	Message body (markdown OK)
title	string	No	Toast title
severity	string	No	Toast style: info (default), warning, error
proxy_id	string	No	Target a specific proxy; omit to fan out to all active proxies

Output

{ "delivered": 2, "message": "..." }

delivered is the count of proxies that received the toast.

Channel Mode (Beta)

Channel mode is experimental and Claude Code only. It uses a forked go-sdk and the --dangerously-load-development-channels flag. Protocol and tool shapes may change.

Channel mode pushes browser errors, diagnostics, and interactions directly into Claude's context as <channel> events — no agnt run PTY wrapper or polling required. channel_reply is the return path. Enable it in .agnt.kdl:

channel {
    enabled true
    reply-tool true   // register channel_reply (default)
}

Then launch Claude Code with the development-channels flag:

claude --dangerously-load-development-channels server:agnt

See Also

• get_incidents — incident inbox the channel forwards from
• proxy — proxy whose overlay receives the toast