diff --git a/api/onnx_web/chain/pipeline.py b/api/onnx_web/chain/pipeline.py
index 26b76fad..8d6c6816 100644
--- a/api/onnx_web/chain/pipeline.py
+++ b/api/onnx_web/chain/pipeline.py
@@ -169,7 +169,7 @@ class ChainPipeline:
             if stage_pipe.max_tile > 0:
                 tile = min(stage_pipe.max_tile, stage_params.tile_size)
 
-            callback.tile = 0 # reset this either way
+            callback.tile = 0  # reset this either way
             if must_tile:
                 logger.info(
                     "image contains sources or is larger than tile size of %s, tiling stage",
@@ -270,7 +270,9 @@ class ChainPipeline:
                 len(stage_sources),
             )
 
-            callback.result = stage_sources # this has just been set to the result of the last stage
+            callback.result = (
+                stage_sources  # this has just been set to the result of the last stage
+            )
 
             if is_debug():
                 for j, image in enumerate(stage_sources.as_image()):
diff --git a/api/onnx_web/server/api.py b/api/onnx_web/server/api.py
index a0310b24..7d1fa79d 100644
--- a/api/onnx_web/server/api.py
+++ b/api/onnx_web/server/api.py
@@ -138,7 +138,7 @@ def image_reply(
             logger.error("metadata and outputs must be the same length")
             return error_reply("metadata and outputs must be the same length")
 
-        data["metadata"] = metadata
+        data["metadata"] = [m.tojson() for m in metadata]
         data["outputs"] = outputs
 
     return jsonify([data])
@@ -673,7 +673,7 @@ def job_status(server: ServerContext, pool: DevicePoolExecutor):
             outputs = None
             metadata = None
             if progress.result is not None and len(progress.result) > 0:
-                # TODO: progress results should be a list of filenames and image metadata
+                # TODO: the names should be attached to the result somehow rather than recomputing them
                 outputs = make_output_names(server, job_name, len(progress.result))
                 metadata = progress.result.metadata
 
diff --git a/api/onnx_web/worker/context.py b/api/onnx_web/worker/context.py
index 39880f54..a052778a 100644
--- a/api/onnx_web/worker/context.py
+++ b/api/onnx_web/worker/context.py
@@ -121,9 +121,7 @@ class WorkerContext:
         with self.idle.get_lock():
             self.idle.value = idle
 
-    def set_progress(
-        self, steps: int, stages: int = 0, tiles: int = 0
-    ) -> None:
+    def set_progress(self, steps: int, stages: int = 0, tiles: int = 0) -> None:
         if self.job is None:
             raise RuntimeError("no job on which to set progress")