nc://permission-canvas

Permission Canvas: element-level permissions for desktop work — allow, read only, ask once, or hide. A Nodecode rewrite of TANGBUDU/permission-canvas by TANGBUDU.

The original wrapped Hermes's computer-use backend and enforced a policy of per-control rules on every capture and every click. Here the same policy engine is the cell: the model asks before it acts, and a person — never the model — writes the rules and grants one exact operation. Nothing leaves the machine: the policy, the approvals and the audit trail are three files in the folder you name.

Get it

Tell the agent "add the permission-canvas cell", or run nodecode add nc://permission-canvas.

Set it up

One setting is required, because the cell keeps its state in files:

{
  "permission-canvas": {
    "dir": "~/permission-canvas",        // policy.json, approvals.json, audit.jsonl
    "default_level": "yellow",           // what a control no rule matches gets
    "unidentified_level": "yellow",      // an unlabeled control in a restricted window
    "approval_ttl_seconds": 120,         // how long one approval waits
    "max_controls": 2000                 // how many controls one observation may carry
  }
}

Until dir is set the cell runs and its verbs refuse, naming the setting. A new folder starts with default_level ask-first, so nothing is allowed by accident.

Use it

Three tools, one for each thing the model may do:

/permission-canvas is the person's side:

/permission-canvas status                     # the policy in force
/permission-canvas rules                      # every rule and its scope
/permission-canvas pending                    # what waits for you
/permission-canvas approve ID                 # allow that exact action, once
/permission-canvas deny ID                    # refuse it; the model is told not to retry
/permission-canvas rule hide role=Button label="Delete account"
/permission-canvas rule allow app=notes.exe role=Button label=Save
/permission-canvas remove r3
/permission-canvas default ask                 # green | blue | yellow | black, or allow/readonly/ask/hide
/permission-canvas unidentified ask
/permission-canvas pause | resume              # stop and start the agent's desktop access
/permission-canvas target 4242 7 notes.exe Notes   # only this window, until `target none`
/permission-canvas block app.exe / unblock app.exe
/permission-canvas hide-title "Secret"          # anything whose title or label matches is hidden

What it holds to:

• A rule matches on app, role, label, label_regex, window_title_regex, pid and window_id. The most restrictive match wins, and a scope field the tree did not report never rules a rule out — except for a green rule, which needs the evidence, so a missing field cannot widen what the model may operate.
• A control with no label, in a window that carries any restriction, gets the unidentified level rather than the default one.
• Something hidden takes its descendants with it, and anything overlapping its rectangle, and anything with no geometry to prove it lies clear of one.
• An approval is one operation: it names the action, the control, its arguments and a digest of the whole policy. It is used once, and editing the policy makes every earlier approval stale.
• Every decision is one line in audit.jsonl.

(help :permission-canvas) has the same, for the agent. /permission-canvas bare prints the status.

What is in it

License

MIT, TANGBUDU's: see LICENSE and NOTICE.