How to set custom helper prompts

Okay, I ended up reusing helpers that are currently available (but not used in our community) and already shipped with Discourse.

Where Setting Set to Rename label (Customize → Text)
Ask AI (posts/topics) ai_helper_translator_agent custom search agent discourse_ai.ai_helper.prompts.translate → custom search label
Composer Translate ai_helper_markdown_tables_agent built-in Translator agent discourse_ai.ai_helper.prompts.markdown_table → Translate
Composer Markdown formatter ai_helper_smart_dates_agent Markdown formatter agent (moved) discourse_ai.ai_helper.prompts.replace_dates → Format as Markdown

Then two snippets:

javascripts/discourse/api-initializers/ai-helper-slots.gjs

import { apiInitializer } from "discourse/lib/api";

const AI_HELPER_ICONS = {
  translate: "ph-dt-magnifying-glass", // for forum search agent
  markdown_table: "ph-dt-translate", // composer: built-in Translator
  replace_dates: "ph-dt-markdown", // composer: Markdown formatter
};

export default apiInitializer((api) => {
  api.getCurrentUser()?.ai_helper_prompts?.forEach((prompt) => {
    prompt.icon = AI_HELPER_ICONS[prompt.name] ?? prompt.icon;
  });
});

common.scss

.ai-composer-helper-menu ul.ai-helper-options li[data-value="translate"] {
  display: none;
}

Note I am using a custom Phosphor icon set; the newicons can be bundled into Font Awesome, Material, or any other icon set.