fix: core binds 17 tools, not ~16, and pin the claim to the list

Operator-facing copy made a factual claim that was already wrong at v0.1.0.
Numbers in prose drift silently, so the test now reads the count out of the
manifest description and asserts it against len(CORE_TOOLS).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01U69poCC3qyCbTnaJmRzBvi

Author: Josh Mabry

protoagent.plugin.yaml

@@ -67,7 +67,7 @@ settings:
     options: [core, full]
     group: "Computer use"
     description: >-
-      “core” binds the documented loop (~16 tools). “full” binds all ~28 and
+      “core” binds the documented loop (17 tools). “full” binds all ~28 and
       costs context on every turn.
   - key: extra_tools
     label: "Extra tools"

tests/test_manifest.py

@@ -98,6 +98,17 @@ def test_extra_tools_hides_when_it_would_be_ignored(m):
     assert driver.tool_filter({"tool_surface": "full", "extra_tools": ["x"]}) is None
 
 
+def test_stated_tool_count_matches_the_code(m):
+    """Operator-facing copy makes a factual claim about how many tools `core`
+    binds. Numbers in prose drift silently — pin it to the list."""
+    import re
+
+    field = next(s for s in m["settings"] if s["key"] == "tool_surface")
+    claimed = re.search(r"(\d+) tools", field["description"])
+    assert claimed, "the tool_surface description should state how many tools 'core' binds"
+    assert int(claimed.group(1)) == len(driver.CORE_TOOLS)
+
+
 def test_declares_no_secrets(m):
     """Nothing to leak — the driver is a local binary, not an API."""
     assert not m.get("secrets")