fix tool-schema

Cargo.toml

@@ -18,7 +18,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.3.38"
+version = "0.3.39"
 edition = "2021"
 license = "Apache-2.0 OR MIT"
 repository = "https://github.com/RightNow-AI/openfang"

crates/openfang-runtime/src/mcp.rs

@@ -200,6 +200,19 @@ impl McpConnection {
                     let input_schema = tool
                         .get("inputSchema")
                         .cloned()
+                        .and_then(|v| {
+                            // Ensure input_schema is a JSON object. MCP servers may
+                            // return it as a string, null, or omit it entirely.
+                            match &v {
+                                serde_json::Value::Object(_) => Some(v),
+                                serde_json::Value::String(s) => {
+                                    serde_json::from_str::<serde_json::Value>(s)
+                                        .ok()
+                                        .filter(|p| p.is_object())
+                                }
+                                _ => None,
+                            }
+                        })
                         .unwrap_or(serde_json::json!({"type": "object"}));
 
                     // Namespace: mcp_{server}_{tool}

crates/openfang-types/src/tool.rs

@@ -56,7 +56,20 @@ pub fn normalize_schema_for_provider(
 fn normalize_schema_recursive(schema: &serde_json::Value) -> serde_json::Value {
     let obj = match schema.as_object() {
         Some(o) => o,
-        None => return schema.clone(),
+        None => {
+            // If the schema is a JSON string, try to parse it as a JSON object.
+            // Some MCP servers / skill definitions serialize schemas as strings.
+            if let Some(s) = schema.as_str() {
+                if let Ok(parsed) = serde_json::from_str::<serde_json::Value>(s) {
+                    if parsed.is_object() {
+                        return normalize_schema_recursive(&parsed);
+                    }
+                }
+            }
+            // Non-object schema (null, number, bool, unparseable string, array) —
+            // return a valid empty object schema so providers don't reject it.
+            return serde_json::json!({"type": "object", "properties": {}});
+        }
     };
 
     let mut result = serde_json::Map::new();
@@ -258,4 +271,52 @@ mod tests {
             .get("$schema")
             .is_none());
     }
+
+    #[test]
+    fn test_normalize_schema_string_parsed_to_object() {
+        // MCP servers may return inputSchema as a JSON string
+        let schema = serde_json::Value::String(
+            r#"{"type":"object","properties":{"query":{"type":"string"}}}"#.to_string(),
+        );
+        let result = normalize_schema_for_provider(&schema, "openai");
+        assert!(result.is_object());
+        assert_eq!(result["type"], "object");
+        assert!(result["properties"]["query"].is_object());
+    }
+
+    #[test]
+    fn test_normalize_schema_null_becomes_empty_object() {
+        let schema = serde_json::Value::Null;
+        let result = normalize_schema_for_provider(&schema, "openai");
+        assert!(result.is_object());
+        assert_eq!(result["type"], "object");
+    }
+
+    #[test]
+    fn test_normalize_schema_unparseable_string_becomes_empty_object() {
+        let schema = serde_json::Value::String("not valid json".to_string());
+        let result = normalize_schema_for_provider(&schema, "openai");
+        assert!(result.is_object());
+        assert_eq!(result["type"], "object");
+    }
+
+    #[test]
+    fn test_normalize_schema_number_becomes_empty_object() {
+        let schema = serde_json::json!(42);
+        let result = normalize_schema_for_provider(&schema, "openai");
+        assert!(result.is_object());
+        assert_eq!(result["type"], "object");
+    }
+
+    #[test]
+    fn test_normalize_schema_string_with_dollar_schema_stripped() {
+        // String schema that contains $schema — should be parsed AND normalized
+        let schema = serde_json::Value::String(
+            r#"{"$schema":"http://json-schema.org/draft-07/schema#","type":"object","properties":{}}"#.to_string(),
+        );
+        let result = normalize_schema_for_provider(&schema, "openai");
+        assert!(result.is_object());
+        assert_eq!(result["type"], "object");
+        assert!(result.get("$schema").is_none());
+    }
 }