openpencil/packages/mcp/tests/tool/scope.test.ts
Victor Wads 68ffd72839
feat(mcp): let MCP clients read only the selection, with a compact get_selection (#732)
* feat(MCP): follow agent activity in canvas

* fix(fig): preserve imported design fidelity

Keep component overrides, variable-backed icon colors, page backgrounds, and fixed text sizing intact across lazy FIG materialization.

* feat: add selection-context MCP tools and mode

* chore: scope work branch to MCP selection and canvas follow

* fix: honor MCP-only tool contracts in CI

* refactor(mcp): drop the follow and selection-context tools this branch carried

Following agents landed in #725, through the agents registry and the
chat's follow toggle, so this branch's MCP follow setting and its
follow-agent module are superseded. The see_user_selection and
get_user_selection_details tools duplicated get_selection, get_node,
describe, get_page_tree, and export_image; the selection-only workflow
they served is rebuilt on those tools in the following commits.

Co-authored-by: Victor Wads <victor@wads.dev>

* feat(mcp): make get_selection the compact entry point with a depth

get_selection returned every selected layer's whole subtree, which is
too much as the first call when the user points at a large frame. It now
returns the selection with direct children by default, counts deeper
children as childCount, and takes a depth.

Co-authored-by: Victor Wads <victor@wads.dev>

* feat(mcp): share only the selection with MCP clients

A selection scope, set with Share only the selection in the local
server settings or OPENPENCIL_MCP_SCOPE=selection, limits MCP clients
to get_selection, get_node, get_page_tree, describe, and export_image
on the selected layers and what they hold.

The server enforces the scope on everything it sends to the app: MCP
sessions and /rpc, which stdio clients also go through, carry only
those tool calls and the session-closed notice, each stamped with the
scope, so a client cannot reach other tools or the settings that would
widen it. The app's bridge rejects node IDs outside the selection,
points describe and export_image at the selection when they name no
nodes, and asks get_page_tree for a root inside it. A stdio client can
ask for the scope itself while the server shares the whole document.

Co-authored-by: Victor Wads <victor@wads.dev>

* fix(mcp): keep selection-scoped clients from writing files or listing wider tools

export_image writes its result to a file when given a path and an MCP
root is set, which reaches past reading the selection. A path is now
refused in selection scope, by the tool registration before the call
and by the app's bridge, so a client with a stale scope cannot write
either; the image itself is still returned.

A stdio client follows the narrower of its own scope and the scope the
server records, instead of letting OPENPENCIL_MCP_SCOPE=document list
tools a selection-scoped server rejects.

Co-authored-by: Victor Wads <victor@wads.dev>

* test(mcp): name the selection scope's tools instead of reading the allowlist

The server test compared the listed tools with SELECTION_SCOPE_TOOLS,
the same list that decides registration, so a tool added to it by
mistake would still pass. It now names the five tools the scope offers.

Co-authored-by: Victor Wads <victor@wads.dev>

---------

Co-authored-by: Danila Poyarkov <dev@dannote.net>
2026-10-07 13:01:28 +00:00

44 lines
1.5 KiB
TypeScript

import { describe, expect, test } from 'bun:test'
import {
isToolEnabled,
narrowestScope,
parseToolScope,
type ToolDescriptor
} from '@open-pencil/mcp/tools'
function tool(name: string): ToolDescriptor {
return {
name,
description: name,
effect: 'read',
availability: 'default',
capabilities: ['document:read'],
enabled: true
}
}
describe('MCP tool scope', () => {
test('reads the scope, defaulting to the document', () => {
expect(parseToolScope(undefined)).toBe('document')
expect(parseToolScope('selection')).toBe('selection')
expect(parseToolScope(' ')).toBe('document')
expect(() => parseToolScope('page')).toThrow(/OPENPENCIL_MCP_SCOPE/)
})
test('keeps only the selection tools in selection scope', () => {
const policy = { allowEval: false, disabledTools: ['describe'], scope: 'selection' as const }
expect(isToolEnabled(tool('get_node'), policy)).toBe(true)
expect(isToolEnabled(tool('delete_node'), policy)).toBe(false)
expect(isToolEnabled(tool('list_documents'), policy)).toBe(false)
// Turning a tool off still applies inside the scope.
expect(isToolEnabled(tool('describe'), policy)).toBe(false)
})
test('a client follows the narrower of its own scope and the server scope', () => {
expect(narrowestScope('selection', 'document')).toBe('selection')
expect(narrowestScope('document', 'selection')).toBe('selection')
expect(narrowestScope('document', 'document')).toBe('document')
})
})