add UnmarshalJSON to Tool (#35)

* add UnmarshalJSON to Tool

* #35 (comment)

* add test

---------

Co-authored-by: Zheng Li <>

Author: xinwo

mcp/tools.go

@@ -72,7 +72,7 @@ type Tool struct {
 	// A human-readable description of the tool.
 	Description string `json:"description,omitempty"`
 	// A JSON Schema object defining the expected parameters for the tool.
-	InputSchema ToolInputSchema `json:"-"` // Hide this from JSON marshaling
+	InputSchema ToolInputSchema `json:"inputSchema"`
 	// Alternative to InputSchema - allows arbitrary JSON Schema to be provided
 	RawInputSchema json.RawMessage `json:"-"` // Hide this from JSON marshaling
 }

mcp/tools_test.go

@@ -73,3 +73,72 @@ func TestToolWithRawSchema(t *testing.T) {
 	assert.True(t, ok)
 	assert.Contains(t, required, "query")
 }
+
+func TestUnmarshalToolWithRawSchema(t *testing.T) {
+	// Create a complex raw schema
+	rawSchema := json.RawMessage(`{
+		"type": "object",
+		"properties": {
+			"query": {"type": "string", "description": "Search query"},
+			"limit": {"type": "integer", "minimum": 1, "maximum": 50}
+		},
+		"required": ["query"]
+	}`)
+
+	// Create a tool with raw schema
+	tool := NewToolWithRawSchema("search-tool", "Search API", rawSchema)
+
+	// Marshal to JSON
+	data, err := json.Marshal(tool)
+	assert.NoError(t, err)
+
+	// Unmarshal to verify the structure
+	var toolUnmarshalled Tool
+	err = json.Unmarshal(data, &toolUnmarshalled)
+	assert.NoError(t, err)
+
+	// Verify tool properties
+	assert.Equal(t, tool.Name, toolUnmarshalled.Name)
+	assert.Equal(t, tool.Description, toolUnmarshalled.Description)
+
+	// Verify schema was properly included
+	assert.Equal(t, "object", toolUnmarshalled.InputSchema.Type)
+	assert.Contains(t, toolUnmarshalled.InputSchema.Properties, "query")
+	assert.Subset(t, toolUnmarshalled.InputSchema.Properties["query"], map[string]interface{}{
+		"type":        "string",
+		"description": "Search query",
+	})
+	assert.Contains(t, toolUnmarshalled.InputSchema.Properties, "limit")
+	assert.Subset(t, toolUnmarshalled.InputSchema.Properties["limit"], map[string]interface{}{
+		"type":    "integer",
+		"minimum": 1.0,
+		"maximum": 50.0,
+	})
+	assert.Subset(t, toolUnmarshalled.InputSchema.Required, []string{"query"})
+}
+
+func TestUnmarshalToolWithoutRawSchema(t *testing.T) {
+	// Create a tool with both schemas set
+	tool := NewTool("dual-schema-tool",
+		WithDescription("A tool with both schemas set"),
+		WithString("input", Description("Test input")),
+	)
+
+	data, err := json.Marshal(tool)
+	assert.Nil(t, err)
+
+	// Unmarshal to verify the structure
+	var toolUnmarshalled Tool
+	err = json.Unmarshal(data, &toolUnmarshalled)
+	assert.NoError(t, err)
+
+	// Verify tool properties
+	assert.Equal(t, tool.Name, toolUnmarshalled.Name)
+	assert.Equal(t, tool.Description, toolUnmarshalled.Description)
+	assert.Subset(t, toolUnmarshalled.InputSchema.Properties["input"], map[string]interface{}{
+		"type":        "string",
+		"description": "Test input",
+	})
+	assert.Empty(t, toolUnmarshalled.InputSchema.Required)
+	assert.Empty(t, toolUnmarshalled.RawInputSchema)
+}