opus-guard
Warning band above the prompt whenever the session is not on an Opus model
newband
Warning band above the prompt whenever the session is not on an Opus model
Born when Claude felt dumb and it turned out to be running Fable 5.1 by accident.
A Claude Code mod that puts a warning band above the prompt whenever the session isn't on an Opus model:
⚠ Not on Opus: this session is running claude-fable-5-1. Switch with /model opus [Dismiss]It checks the live model on every redraw, after /model switches, and after each turn, so a fallback mid-session shows up too. Dismiss hides it until the model changes again.
Every hook only reads; none changes what passes through it.
session.start, turn.complete: read the session's model.classic.PostModelSwitch: reads the model a /model switch landed on, to redraw the band. It doesn't change the switch or settings.ui.render (AbovePrompt): draws the warning when the model isn't Opus, and passes otherwise. It steps aside while a survey holds the band.It makes no network calls and writes no files; the one value it keeps is which model you dismissed the warning for.
At the prompt of a terminal session:
/plugin install opus-guard --marketplace acidprime/opus-guardAnswer y to add the marketplace, then pick a scope (user is the usual one).
From a shell:
claude plugin install opus-guard --marketplace acidprime/opus-guardIn the desktop app: click + next to the prompt box, then Plugins, Add marketplace with acidprime/opus-guard, then Add plugin.
claude plugin validate .
claude plugin test .MIT. See LICENSE. Privacy: PRIVACY.md.
hooks/register.tsx 58 lines1import { atom, read, update } from 'claude-code'
2import type { Register } from 'claude-code'
3
4const model = atom({ plugin: 'opus-guard', key: 'model' } as const, null)
5const dismissedFor = atom({ plugin: 'opus-guard', key: 'dismissedFor' } as const, null)
6
7export const isOpus = (m: string) => /opus/i.test(m)
8
9export const register: Register = on => {
10 on('session.start', async ($, e, next) => {
11 const current = await $.session.model()
12 await update($, model, () => current)
13 return next(e)
14 })
15
16 on('classic.PostModelSwitch', async ($, e, next) => {
17 await update($, model, () => e.to_model)
18 return next(e)
19 })
20
21 // Catches changes no switch event reports, like a fallback mid-turn.
22 on('turn.complete', async ($, e, next) => {
23 const current = await $.session.model()
24 if (current !== (await read($, model))) {
25 await update($, model, () => current)
26 }
27 return next(e)
28 })
29
30 // Reads the live model on every draw: the atom writes above only trigger
31 // redraws, and PostModelSwitch never fires where an organization manages
32 // Claude Code.
33 on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
34 const current = (await $.session.model()) || (await read($, model))
35 if (e.props.hasSurvey || current === null || isOpus(current)) {
36 return next(e)
37 }
38 if ((await read($, dismissedFor)) === current) {
39 return next(e)
40 }
41
42 const { Box, Button, Text } = $.ui.resolve(e)
43
44 return (
45 <Box>
46 <Text color="warning" bold>
47 ⚠ Not on Opus: this session is running {current}. Switch with /model opus{' '}
48 </Text>
49 <Button
50 key="dismiss"
51 label="Dismiss"
52 onPress={() => update($, dismissedFor, () => current)}
53 />
54 </Box>
55 )
56 })
57}
58types/index.d.ts 6 lines1declare module 'claude-code' {
2 interface PluginState {
3 'opus-guard': { model: string | null; dismissedFor: string | null }
4 }
5}
6