extend schema mapping

golem-worker-service/src/mcp/agent_mcp_capability.rs

@@ -14,7 +14,7 @@
 
 use crate::mcp::agent_mcp_resource::AgentMcpResource;
 use crate::mcp::agent_mcp_tool::AgentMcpTool;
-use crate::mcp::mcp_schema::{GetMcpSchema, GetMcpToolSchema, McpToolSchema};
+use crate::mcp::schema::{GetMcpSchema, GetMcpToolSchema, McpSchema, McpToolSchema};
 use golem_common::base_model::account::AccountId;
 use golem_common::base_model::agent::{AgentMethod, AgentTypeName, DataSchema};
 use golem_common::base_model::component::ComponentId;
@@ -50,8 +50,10 @@ impl McpAgentCapability {
                     );
 
                     let constructor_schema = constructor.input_schema.get_mcp_schema();
+
                     let mut tool_schema = method.get_mcp_tool_schema();
-                    tool_schema.merge_input_schema(constructor_schema);
+
+                    tool_schema.prepend_input_schema(constructor_schema);
 
                     let McpToolSchema {
                         input_schema,
@@ -62,8 +64,9 @@ impl McpAgentCapability {
                         name: Cow::from(get_tool_name(agent_type_name, method)),
                         title: None,
                         description: Some(method.description.clone().into()),
-                        input_schema: Arc::new(input_schema),
-                        output_schema: output_schema.map(Arc::new),
+                        input_schema: Arc::new(McpSchema::from(input_schema)),
+                        output_schema: output_schema
+                            .map(|internal| Arc::new(McpSchema::from(internal))),
                         annotations: None,
                         execution: None,
                         icons: None,

golem-worker-service/src/mcp/agent_mcp_server.rs

@@ -23,6 +23,7 @@ use golem_common::base_model::agent::{
 use golem_common::base_model::domain_registration::Domain;
 use golem_common::model::WorkerId;
 use golem_common::model::agent::{NamedElementSchema, UntypedDataValue, UntypedElementValue};
+use golem_wasm::analysis::AnalysedType;
 use golem_wasm::json::ValueAndTypeJsonExtensions;
 use golem_wasm::{IntoValue, ValueAndType};
 use poem::http;
@@ -186,12 +187,19 @@ where
             {
                 match elem_schema {
                     ElementSchema::ComponentModel(ComponentModelElementSchema { element_type }) => {
-                        let value = args_map
-                            .get(name)
-                            .ok_or_else(|| format!("Missing parameter: {}", name))?;
+                        let json_value = match args_map.get(name) {
+                            Some(value) => value.clone(),
+                            None => {
+                                if matches!(element_type, AnalysedType::Option(_)) {
+                                    serde_json::Value::Null
+                                } else {
+                                    return Err(format!("Missing parameter: {}", name));
+                                }
+                            }
+                        };
 
                         let value_and_type =
-                            golem_wasm::ValueAndType::parse_with_type(value, element_type)
+                            golem_wasm::ValueAndType::parse_with_type(&json_value, element_type)
                                 .map_err(|errs| {
                                     format!(
                                         "Failed to parse parameter '{}': {}",

golem-worker-service/src/mcp/mod.rs

@@ -7,4 +7,4 @@ mod agent_mcp_resource;
 mod agent_mcp_server;
 mod agent_mcp_tool;
 mod mcp_capabilities_lookup;
-mod mcp_schema;
+mod schema;