Validate tool params and add tests

tests/test_tool_validation.py

@@ -0,0 +1,88 @@
+from typing import Any
+
+from nanobot.agent.tools.base import Tool
+from nanobot.agent.tools.registry import ToolRegistry
+
+
+class SampleTool(Tool):
+    @property
+    def name(self) -> str:
+        return "sample"
+
+    @property
+    def description(self) -> str:
+        return "sample tool"
+
+    @property
+    def parameters(self) -> dict[str, Any]:
+        return {
+            "type": "object",
+            "properties": {
+                "query": {"type": "string", "minLength": 2},
+                "count": {"type": "integer", "minimum": 1, "maximum": 10},
+                "mode": {"type": "string", "enum": ["fast", "full"]},
+                "meta": {
+                    "type": "object",
+                    "properties": {
+                        "tag": {"type": "string"},
+                        "flags": {
+                            "type": "array",
+                            "items": {"type": "string"},
+                        },
+                    },
+                    "required": ["tag"],
+                },
+            },
+            "required": ["query", "count"],
+        }
+
+    async def execute(self, **kwargs: Any) -> str:
+        return "ok"
+
+
+def test_validate_params_missing_required() -> None:
+    tool = SampleTool()
+    errors = tool.validate_params({"query": "hi"})
+    assert "missing required count" in "; ".join(errors)
+
+
+def test_validate_params_type_and_range() -> None:
+    tool = SampleTool()
+    errors = tool.validate_params({"query": "hi", "count": 0})
+    assert any("count must be >= 1" in e for e in errors)
+
+    errors = tool.validate_params({"query": "hi", "count": "2"})
+    assert any("count should be integer" in e for e in errors)
+
+
+def test_validate_params_enum_and_min_length() -> None:
+    tool = SampleTool()
+    errors = tool.validate_params({"query": "h", "count": 2, "mode": "slow"})
+    assert any("query must be at least 2 chars" in e for e in errors)
+    assert any("mode must be one of" in e for e in errors)
+
+
+def test_validate_params_nested_object_and_array() -> None:
+    tool = SampleTool()
+    errors = tool.validate_params(
+        {
+            "query": "hi",
+            "count": 2,
+            "meta": {"flags": [1, "ok"]},
+        }
+    )
+    assert any("missing required meta.tag" in e for e in errors)
+    assert any("meta.flags[0] should be string" in e for e in errors)
+
+
+def test_validate_params_ignores_unknown_fields() -> None:
+    tool = SampleTool()
+    errors = tool.validate_params({"query": "hi", "count": 2, "extra": "x"})
+    assert errors == []
+
+
+async def test_registry_returns_validation_error() -> None:
+    reg = ToolRegistry()
+    reg.register(SampleTool())
+    result = await reg.execute("sample", {"query": "hi"})
+    assert "Invalid parameters" in result