fumi-script

name	fumi-script
description	Create a new fumi host script in ~/.config/fumi/scripts/ that fumi actions can invoke via fumi.run
argument-hint	<what the script should do, e.g. "append a JSON line to ~/notes/prs.ndjson">

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

Request

$ARGUMENTS

Steps

1. Pick the language. Default to bash for simple I/O, python3 for JSON munging, node only if needed. Ask if unclear.

2. Pick a path under ~/.config/fumi/scripts/. Subdirectories are fine (notes/append.py). Confirm it doesn't already exist.

3. Write the file with a shebang on line 1 and set -euo pipefail (bash) or equivalent. Read the entire payload from stdin to EOF, then process it.

4. chmod +x the file — without the owner-executable bit, fumi rejects it with SCRIPT_NOT_EXECUTABLE.

5. Test from the CLI before wiring it into an action:

   fumi scripts run <relpath> --payload '{"...":"..."}'
   

6. Tell the user how to call it from an action: await fumi.run('<relpath>', payload). Offer the fumi-action skill if they need one.

Invocation contract (preserve when writing scripts)

• Argv: only argv[0]. No user-controlled arguments are ever passed — payload is stdin only.
• Stdin: raw JSON encoding of payload, single write, no trailing newline. If payload is absent/null, the literal bytes null are written. Stdin closes after the write.
• Cwd: the directory containing the script. Relative paths resolve next to the script.
• No shell: exec'd directly, no sh -c, no expansion. Do not try to interpolate payload into a command line — parse it as JSON.
• Env: inherited, but all FUMI_* are stripped, then FUMI_STORE is re-set to the store root. The variable name store is reserved.

Hard rules

• Shebang required (#!/usr/bin/env bash, #!/usr/bin/env python3, etc.).
• Owner-executable bit required (chmod +x).
• No symlinks — fumi rejects them. To share code, copy or hard-link.
• Stdout capped at 768 KiB, stderr at 128 KiB. Overflow rejects the call with EXEC_OUTPUT_TOO_LARGE. For bulk data, write to a file and return the path.
• Default timeout 30 s; on timeout the script gets SIGTERM, then SIGKILL after 500 ms. For background work, spawn a detached process and return immediately.
• Treat the payload as untrusted — even if the action is yours, the page DOM can be hostile. Parse JSON, never eval or interpolate into a shell command.
• Fail loudly: non-zero exit + descriptive stderr beats silent success with an error in stdout.

Bash skeleton

#!/usr/bin/env bash
set -euo pipefail

payload="$(cat)"
field=$(jq -r '.field' <<<"$payload")

# … do the thing …

printf '%s\n' "ok"

Python skeleton

#!/usr/bin/env python3
import json, sys

payload = json.load(sys.stdin)
# … do the thing …
print("ok")