Support and integration for Claude mods

[edgan]

T3 Code needs to add support and integration for Claude mods. Without it people will migrate back to Claude Desktop, Claude Code(TUI), or other solutions to get it.

Official documentation:
https://code.claude.com/docs/en/plugins/mods/overview

[edgan]

Most mods probably work. I have had Claude implement a mod to replace a Stop hook that asks questions instead of just telling the model no.

But part of the point is to rewrite the UI too, and that is the most powerful part, like adding buttons dynamically.

[sigvardt]

+1 from me. The concrete one i'm missing is the built-in "You should know" mod (cc-plugin-you-should-know). Its side agent runs fine under the Agent SDK, but its notes render above the prompt, so in T3 they never show up.

Even a minimal surface would cover alot: render mod notes/bands above the composer and mod panes in the side panel, and fall back to a transcript line for anything T3 can't draw.

[jobsingles]

+1, and here is a small, concrete first step that needs no new UI system: the Agent SDK already sends a mod's toast, status line and log lines to T3 Code. They are just dropped.

I tested a minimal mod against Claude Code 2.1.292 with claude -p --input-format stream-json --output-format stream-json --verbose, the same way T3 Code runs Claude:

on('prompt.submit', async ($, e, next) => {
  $.ui.toast('PROBE-TOAST')
  $.ui.status('PROBE-STATUS')
  $.ui.log('PROBE-LOG')
  return next(e)
})

The stream then contains:

{"type":"system","subtype":"ui_toast","plugin":"surfaceprobe","text":"PROBE-TOAST","timeout_ms":4000, ...}
{"type":"system","subtype":"ui_status","plugin":"surfaceprobe","text":"PROBE-STATUS", ...}
{"type":"system","subtype":"ui_log","plugin":"surfaceprobe","text":"PROBE-LOG", ...}

ClaudeAdapterV2.ts has no case for ui_toast, ui_status or ui_log, so none of it reaches the thread.

In contrast, a mod that drops a prompt (prompt.submit returning { drop: reason }) arrives as {"type":"system","subtype":"informational","level":"warning","prevent_continuation":true}, and T3 Code 0.0.45 does show it: "Prompt dropped by a hook: …" (checked in a real thread). So the plumbing exists for one message type already.

Suggested mapping:

• ui_toast → the app's normal toast, using timeout_ms
• ui_status → a small per-plugin status text near the composer or in the thread header, cleared when a mod sends an empty status
• ui_log → a dim line in the thread timeline

That covers a large share of real mods without panes: cost and rate-limit warnings, "cache is cold" warnings (cache-tax), cron/job status, "new message" notifications. Mod authors can keep panes for the terminal and still reach T3 users.

Related: #17418 / #17432 (commands that mods register missing from the / menu) and #17531 (mods that wait on a pane hang in T3).

Setup: T3 Code 0.0.45 on Linux, Claude Code 2.1.292.

_{Investigated and drafted with Claude Code; the stream output above is verbatim from the test run.}