fumi-action

name	fumi-action
description	Create a new fumi action (userscript) in ~/.config/fumi/actions/ for the fumi Chrome extension
argument-hint	<what the action should do, e.g. "add a copy-PR-title button on github PRs">

Create a new fumi action based on the user's request.

Request

$ARGUMENTS

Steps

1. Pick a filename and ID. Lowercase kebab-case <id>.js. The @id is derived from the filename by lowercasing and replacing non-alphanumerics with -. If unsure, ask the user for the target site and a short slug.

2. Choose @match patterns. Use Chrome match patterns (https://github.com/*/pull/*, *://*.example.com/*, <all_urls>). Add @exclude only if needed. Confirm scope with the user when ambiguous — narrower is safer.

3. Check for collisions. List ~/.config/fumi/actions/ and ensure neither the filename nor the derived @id already exist.

4. Write the file to ~/.config/fumi/actions/<id>.js with the frontmatter block first, then the action body wrapped in an IIFE. Example skeleton:

   // ==Fumi Action==
   // @id <id>
   // @match <pattern>
   // ==/Fumi Action==
   
   (() => {
     // action code
   })();
   

5. Tell the user how to load it. Open the fumi extension popup → click Reload actions → reload the target page. Edits do not hot-reload.

Hard rules

• Frontmatter is required. Only @id, @match, @exclude are recognized — any other directive causes the file to be rejected (not ignored). Directive names must be lowercase.
• @match must appear at least once. @id and @exclude are optional. @match and @exclude may repeat.
• The action runs in Chrome's USER_SCRIPT world at document_idle. It cannot touch page globals directly, cannot use chrome.* APIs, and has no persistent storage.
• SPA navigation (GitHub turbo, pjax) does not re-inject. If the target site is an SPA, hook turbo:load / pjax:end and/or use a MutationObserver like actions/github-scroll-to-top.js does.
• To call a host script, use await fumi.run(scriptPath, payload, { timeoutMs? }). scriptPath is relative to ~/.config/fumi/scripts/, no leading /, no ... Resolves with { exitCode, stdout, stderr, durationMs }; rejects only when the script never spawned. If the action needs a host script that doesn't exist yet, offer to create it via the fumi-script skill.
• Treat anything from the DOM as untrusted when building payloads — the page can be hostile.
• Stdout cap from fumi.run is 768 KiB, stderr 128 KiB; default timeout 30 s.

Style

• Wrap the action body in an IIFE to avoid leaking globals.
• Use a stable element ID prefix (fumi-...) and check for existence before re-creating DOM.
• No external dependencies — these are plain scripts loaded by Chrome.
• Keep it minimal: no error handling for impossible cases, no abstractions you don't need.