fix: preserve trailing decimal zeros in number inputs (e.g. 1.0)

client/src/components/DynamicJsonForm.tsx

@@ -487,7 +487,12 @@ const DynamicJsonForm = forwardRef<DynamicJsonFormRef, DynamicJsonFormProps>(
                 if (!isNaN(num)) {
                   handleFieldChange(path, num);
                 }
-                clearNumericDraft(path);
+                // Keep the draft if the raw text differs from the
+                // stringified number (e.g. "1.0" vs "1") so the
+                // display preserves the user's decimal notation.
+                if (val === String(num)) {
+                  clearNumericDraft(path);
+                }
               }}
               placeholder={propSchema.description}
               required={isRequired}

client/src/components/ToolsTab.tsx

@@ -199,6 +199,9 @@ const ToolsTab = ({
   serverSupportsTaskRequests: boolean;
 }) => {
   const [params, setParams] = useState<Record<string, unknown>>({});
+  const [numericDrafts, setNumericDrafts] = useState<Record<string, string>>(
+    {},
+  );
   const [runAsTask, setRunAsTask] = useState(false);
   const [isToolRunning, setIsToolRunning] = useState(false);
   const [isOutputSchemaExpanded, setIsOutputSchemaExpanded] = useState(false);
@@ -241,6 +244,7 @@ const ToolsTab = ({
       ];
     });
     setParams(Object.fromEntries(params));
+    setNumericDrafts({});
     const toolTaskSupport = serverSupportsTaskRequests
       ? getTaskSupport(selectedTool)
       : "forbidden";
@@ -521,20 +525,29 @@ const ToolsTab = ({
                               name={key}
                               placeholder={prop.description}
                               value={
-                                params[key] === undefined
-                                  ? ""
-                                  : String(params[key])
+                                Object.prototype.hasOwnProperty.call(
+                                  numericDrafts,
+                                  key,
+                                )
+                                  ? numericDrafts[key]
+                                  : params[key] === undefined
+                                    ? ""
+                                    : String(params[key])
                               }
                               onChange={(e) => {
                                 const value = e.target.value;
+                                setNumericDrafts((prev) => ({
+                                  ...prev,
+                                  [key]: value,
+                                }));
                                 if (value === "") {
                                   // Field cleared - set to undefined
                                   setParams({
                                     ...params,
                                     [key]: undefined,
                                   });
                                 } else {
-                                  // Field has value - try to convert to number, but store input either way
+                                  // Field has value - try to convert to number
                                   const num = Number(value);
                                   if (!isNaN(num)) {
                                     setParams({
@@ -550,6 +563,28 @@ const ToolsTab = ({
                                   }
                                 }
                               }}
+                              onBlur={(e) => {
+                                const val = e.target.value;
+                                if (!val) {
+                                  setNumericDrafts((prev) => {
+                                    const next = { ...prev };
+                                    delete next[key];
+                                    return next;
+                                  });
+                                  return;
+                                }
+                                const num = Number(val);
+                                if (
+                                  prop.type === "integer" ||
+                                  val === String(num)
+                                ) {
+                                  setNumericDrafts((prev) => {
+                                    const next = { ...prev };
+                                    delete next[key];
+                                    return next;
+                                  });
+                                }
+                              }}
                               className="mt-1"
                             />
                           ) : (

client/src/components/__tests__/DynamicJsonForm.test.tsx

@@ -425,6 +425,48 @@ describe("DynamicJsonForm Number Fields", () => {
       fireEvent.change(input, { target: { value: "-74.01" } });
       expect(input.value).toBe("-74.01");
     });
+
+    it("should preserve decimal zero after blur", () => {
+      const schema: JsonSchemaType = {
+        type: "number",
+        description: "Coordinate",
+      };
+
+      const WrappedForm = () => {
+        const [value, setValue] = useState<number>(0);
+        return (
+          <DynamicJsonForm schema={schema} value={value} onChange={setValue} />
+        );
+      };
+
+      render(<WrappedForm />);
+      const input = screen.getByRole("spinbutton") as HTMLInputElement;
+
+      fireEvent.change(input, { target: { value: "1.0" } });
+      fireEvent.blur(input);
+      expect(input.value).toBe("1.0");
+    });
+
+    it("should not preserve decimal zero for integer fields after blur", () => {
+      const schema: JsonSchemaType = {
+        type: "integer",
+        description: "Count",
+      };
+
+      const WrappedForm = () => {
+        const [value, setValue] = useState<number>(0);
+        return (
+          <DynamicJsonForm schema={schema} value={value} onChange={setValue} />
+        );
+      };
+
+      render(<WrappedForm />);
+      const input = screen.getByRole("spinbutton") as HTMLInputElement;
+
+      fireEvent.change(input, { target: { value: "1.0" } });
+      fireEvent.blur(input);
+      expect(input.value).toBe("1");
+    });
   });
 });