diff --git a/docs/tools.md b/docs/tools.md
index ed699ee..a98ab02 100644
--- a/docs/tools.md
+++ b/docs/tools.md
@@ -166,6 +166,8 @@ multipart clients.
 PATCH `/projects/{project_id}/issues/{issue_id}/issue-attachments/{asset_id}/`.
 
 Required: `project_id`, `issue_id`, `asset_id`.
+Returns `{ "completed": true, "asset_id": "..." }`. When Plane returns a
+non-empty response body, it is available under `result`.
 
 ### `plane_attachment_upload`
 
diff --git a/internal/mcpserver/server_test.go b/internal/mcpserver/server_test.go
index 4eb5e59..ee15358 100644
--- a/internal/mcpserver/server_test.go
+++ b/internal/mcpserver/server_test.go
@@ -492,6 +492,42 @@ func TestAttachmentInitUploadRawReturnsFullPayload(t *testing.T) {
 	require.Equal(t, "secret-policy", fields["policy"])
 }
 
+func TestAttachmentCompleteUploadReturnsStructuredSuccessForNoContent(t *testing.T) {
+	srv := newTestServer(t, func(w http.ResponseWriter, r *http.Request) {
+		require.Equal(t, http.MethodPatch, r.Method)
+		require.Equal(t, "/api/v1/workspaces/ws/projects/P/issues/I/issue-attachments/asset-1/", r.URL.Path)
+		w.WriteHeader(http.StatusNoContent)
+	})
+
+	payload := callToolPayload(t, srv, "plane_attachment_complete_upload", map[string]any{
+		"project_id": "P",
+		"issue_id":   "I",
+		"asset_id":   "asset-1",
+	})
+	require.Equal(t, true, payload["completed"])
+	require.Equal(t, "asset-1", payload["asset_id"])
+	require.NotContains(t, payload, "result")
+}
+
+func TestAttachmentCompleteUploadPreservesPlaneResult(t *testing.T) {
+	srv := newTestServer(t, func(w http.ResponseWriter, r *http.Request) {
+		require.Equal(t, http.MethodPatch, r.Method)
+		require.Equal(t, "/api/v1/workspaces/ws/projects/P/issues/I/issue-attachments/asset-1/", r.URL.Path)
+		_, _ = w.Write([]byte(`{"id":"asset-1","status":"uploaded"}`))
+	})
+
+	payload := callToolPayload(t, srv, "plane_attachment_complete_upload", map[string]any{
+		"project_id": "P",
+		"issue_id":   "I",
+		"asset_id":   "asset-1",
+	})
+	require.Equal(t, true, payload["completed"])
+	require.Equal(t, "asset-1", payload["asset_id"])
+	result, ok := payload["result"].(map[string]any)
+	require.True(t, ok)
+	require.Equal(t, "uploaded", result["status"])
+}
+
 func TestAttachmentMimeTypeStripsParameters(t *testing.T) {
 	require.Equal(t, "text/plain", attachmentMimeType("notes.txt"))
 	require.Equal(t, "application/octet-stream", attachmentMimeType("archive.unknownext"))
diff --git a/internal/mcpserver/tools_attachments.go b/internal/mcpserver/tools_attachments.go
index b812e70..990cf1e 100644
--- a/internal/mcpserver/tools_attachments.go
+++ b/internal/mcpserver/tools_attachments.go
@@ -114,7 +114,7 @@ func (s *Server) handleAttachmentCompleteUpload(ctx context.Context, req mcp.Cal
 	if err != nil {
 		return toolError(err), nil
 	}
-	return asTextResult(out)
+	return asTextResult(completeAttachmentUploadResult(assetID, out))
 }
 
 func (s *Server) handleAttachmentUpload(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
@@ -293,6 +293,17 @@ func compactAttachmentInitUpload(init map[string]any) map[string]any {
 	return out
 }
 
+func completeAttachmentUploadResult(assetID string, planeResult map[string]any) map[string]any {
+	out := map[string]any{
+		"completed": true,
+		"asset_id":  assetID,
+	}
+	if len(planeResult) > 0 {
+		out["result"] = planeResult
+	}
+	return out
+}
+
 func initUploadAssetID(init map[string]any) string {
 	for _, key := range []string{"id", "asset_id"} {
 		if value, ok := init[key].(string); ok && value != "" {