Fix kb.capabilities OpenClaw compat source

src/vouch/capabilities.py

@@ -7,10 +7,19 @@
 
 from __future__ import annotations
 
+import json
+import logging
+from pathlib import Path
+
 from . import __version__
 from .models import Capabilities
 from .openclaw.context_engine import describe_engine
 
+_log = logging.getLogger(__name__)
+
+# package.json is the authoritative source for the OpenClaw pluginApi range.
+_PACKAGE_JSON_PATH = Path(__file__).resolve().parent.parent.parent / "package.json"
+
 # The full method surface this implementation exposes. Keep this list in
 # sync with the MCP server + JSONL server registrations — `test_capabilities`
 # asserts they match.
@@ -76,6 +85,24 @@
 ]
 
 
+def _load_host_compat() -> dict[str, dict[str, str]]:
+    """Read the `openclaw.compat` block from package.json (#237).
+
+    Surfaced in `kb.capabilities` as `host_compat` so non-OpenClaw clients
+    can detect compat without parsing package metadata themselves. Returns an
+    empty dict if package.json is missing or malformed.
+    """
+    try:
+        package_json = json.loads(_PACKAGE_JSON_PATH.read_text(encoding="utf-8"))
+    except (OSError, json.JSONDecodeError) as e:
+        _log.debug("package.json unreadable, host_compat will be empty: %s", e)
+        return {}
+    compat = package_json.get("openclaw", {}).get("compat")
+    if not isinstance(compat, dict):
+        return {}
+    return {"openclaw": {k: str(v) for k, v in compat.items()}}
+
+
 def capabilities() -> Capabilities:
     retrieval = ["fts5", "substring"]
     try:
@@ -98,4 +125,5 @@ def capabilities() -> Capabilities:
             "config_path": "retrieval.scope",
         },
         context_engines=[describe_engine()],
+        host_compat=_load_host_compat(),
     )

src/vouch/models.py

@@ -457,3 +457,12 @@ class Capabilities(BaseModel):
         default_factory=list,
         description="OpenClaw context engines exposed (see openclaw.plugin.json)",
     )
+    host_compat: dict[str, Any] = Field(
+        default_factory=dict,
+        description=(
+            "Per-host compatibility ranges (#237). Mirrors the "
+            "`openclaw.compat` block in package.json so non-OpenClaw "
+            "clients can detect compat without parsing the package metadata, "
+            'e.g. {"openclaw": {"pluginApi": ">=2026.6.0"}}.'
+        ),
+    )

tests/test_capabilities.py

@@ -2,6 +2,11 @@
 
 from __future__ import annotations
 
+import json
+from pathlib import Path
+
+import pytest
+
 from vouch import capabilities
 from vouch.jsonl_server import HANDLERS
 
@@ -15,3 +20,45 @@ def test_capabilities_matches_jsonl_handlers() -> None:
         f"missing handlers={declared - implemented}, "
         f"missing capabilities={implemented - declared}"
     )
+
+
+_PACKAGE_JSON_PATH = Path(__file__).resolve().parent.parent / "package.json"
+
+
+def _package_plugin_api() -> str:
+    package_json = json.loads(_PACKAGE_JSON_PATH.read_text(encoding="utf-8"))
+    return package_json["openclaw"]["compat"]["pluginApi"]
+
+
+def test_capabilities_host_compat_matches_package_json() -> None:
+    caps = capabilities.capabilities()
+    package_range = _package_plugin_api()
+    capabilities_range = caps.host_compat.get("openclaw", {}).get("pluginApi")
+    assert capabilities_range == package_range, (
+        f"host compat drift: package.json declares pluginApi={package_range!r} "
+        f"but kb.capabilities.host_compat reports {capabilities_range!r}. "
+        f"Keep both in sync."
+    )
+
+
+def test_capabilities_host_compat_present_and_nonempty() -> None:
+    caps = capabilities.capabilities()
+    assert "openclaw" in caps.host_compat
+    assert "pluginApi" in caps.host_compat["openclaw"]
+    assert caps.host_compat["openclaw"]["pluginApi"].strip() != ""
+
+
+def test_load_host_compat_returns_empty_on_missing_package_json(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path,
+) -> None:
+    monkeypatch.setattr(capabilities, "_PACKAGE_JSON_PATH", tmp_path / "does-not-exist.json")
+    assert capabilities._load_host_compat() == {}
+
+
+def test_load_host_compat_returns_empty_on_malformed_package_json(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path,
+) -> None:
+    bad = tmp_path / "package.json"
+    bad.write_text("{not valid json", encoding="utf-8")
+    monkeypatch.setattr(capabilities, "_PACKAGE_JSON_PATH", bad)
+    assert capabilities._load_host_compat() == {}