diff --git a/packages/client/src/file/builder.rs b/packages/client/src/file/builder.rs
index cbe2942f6..ab4cd39cd 100644
--- a/packages/client/src/file/builder.rs
+++ b/packages/client/src/file/builder.rs
@@ -65,6 +65,7 @@ impl Builder {
 				.collect(),
 			executable: self.executable,
 			module: self.module,
+			size: None,
 		}))
 	}
 }
diff --git a/packages/client/src/graph/data.rs b/packages/client/src/graph/data.rs
index a56bb2653..ac9f79f9b 100644
--- a/packages/client/src/graph/data.rs
+++ b/packages/client/src/graph/data.rs
@@ -155,6 +155,10 @@ pub struct File {
 	#[serde(default, skip_serializing_if = "Option::is_none")]
 	#[tangram_serialize(id = 3, default, skip_serializing_if = "Option::is_none")]
 	pub module: Option<tg::module::Kind>,
+
+	#[serde(default, skip_serializing_if = "Option::is_none")]
+	#[tangram_serialize(id = 4, default, skip_serializing_if = "Option::is_none")]
+	pub size: Option<u64>,
 }
 
 #[serde_as]
diff --git a/packages/client/src/graph/object.rs b/packages/client/src/graph/object.rs
index a4d9e8682..3f9712719 100644
--- a/packages/client/src/graph/object.rs
+++ b/packages/client/src/graph/object.rs
@@ -48,6 +48,7 @@ pub struct File {
 	pub dependencies: BTreeMap<tg::Reference, Option<Dependency>>,
 	pub executable: bool,
 	pub module: Option<tg::module::Kind>,
+	pub size: Option<u64>,
 }
 
 #[derive(Clone, Debug)]
@@ -288,11 +289,13 @@ impl File {
 			.collect();
 		let executable = self.executable;
 		let module = self.module;
+		let size = self.size;
 		tg::graph::data::File {
 			contents,
 			dependencies,
 			executable,
 			module,
+			size,
 		}
 	}
 
@@ -319,11 +322,13 @@ impl File {
 			.collect::<tg::Result<_>>()?;
 		let executable = data.executable;
 		let module = data.module;
+		let size = data.size;
 		let file = tg::graph::File {
 			contents,
 			dependencies,
 			executable,
 			module,
+			size,
 		};
 		Ok(file)
 	}
diff --git a/packages/client/src/value/parse.rs b/packages/client/src/value/parse.rs
index e69486de2..ec45d72e4 100644
--- a/packages/client/src/value/parse.rs
+++ b/packages/client/src/value/parse.rs
@@ -394,6 +394,7 @@ fn directory_node_entry(input: &mut Input) -> ModalResult<tg::graph::Edge<tg::Ar
 	alt((
 		string.map(|s| {
 			let bytes = Bytes::from(s.into_bytes());
+			let size = bytes.len().to_u64().unwrap();
 			let leaf = tg::blob::object::Leaf { bytes };
 			let blob_object = tg::blob::Object::Leaf(leaf);
 			let blob = tg::Blob::with_object(blob_object);
@@ -402,6 +403,7 @@ fn directory_node_entry(input: &mut Input) -> ModalResult<tg::graph::Edge<tg::Ar
 				dependencies: BTreeMap::new(),
 				executable: false,
 				module: None,
+				size: Some(size),
 			};
 			let object = tg::file::Object::Node(node);
 			let file = tg::File::with_object(object);
@@ -428,6 +430,7 @@ fn file_string(input: &mut Input) -> ModalResult<tg::Object> {
 	string
 		.map(|s| {
 			let bytes = Bytes::from(s.into_bytes());
+			let size = bytes.len().to_u64().unwrap();
 			let leaf = tg::blob::object::Leaf { bytes };
 			let blob_object = tg::blob::Object::Leaf(leaf);
 			let blob = tg::Blob::with_object(blob_object);
@@ -436,6 +439,7 @@ fn file_string(input: &mut Input) -> ModalResult<tg::Object> {
 				dependencies: BTreeMap::new(),
 				executable: false,
 				module: None,
+				size: Some(size),
 			};
 			let object = tg::file::Object::Node(node);
 			tg::File::with_object(object).into()
@@ -467,6 +471,7 @@ fn file_node(input: &mut Input) -> ModalResult<tg::Object> {
 		let mut dependencies = BTreeMap::new();
 		let mut executable = false;
 		let mut module = None;
+		let mut size = None;
 		for (key, value) in entries {
 			match key.as_str() {
 				"contents" => {
@@ -519,6 +524,16 @@ fn file_node(input: &mut Input) -> ModalResult<tg::Object> {
 						.map_err(|_| tg::error!("expected a module kind"))?;
 					module.replace(value);
 				},
+				"size" => {
+					let value = value
+						.try_unwrap_number_ref()
+						.map_err(|_| tg::error!("expected number for size"))?;
+					size = Some(
+						value
+							.to_u64()
+							.ok_or_else(|| tg::error!("size must be a non-negative integer"))?,
+					);
+				},
 				_ => {
 					return Err(tg::error!("unexpected field in file: {}", key));
 				},
@@ -530,6 +545,7 @@ fn file_node(input: &mut Input) -> ModalResult<tg::Object> {
 			dependencies,
 			executable,
 			module,
+			size,
 		};
 		let object = tg::file::Object::Node(node);
 		Ok(tg::File::with_object(object).into())
@@ -1096,6 +1112,7 @@ fn parse_graph_node(map: &tg::value::Map) -> tg::Result<tg::graph::Node> {
 	let mut dependencies = BTreeMap::new();
 	let mut executable = false;
 	let mut module = None;
+	let mut size = None;
 	let mut artifact = None;
 	let mut path = None;
 	for (key, value) in map {
@@ -1177,6 +1194,16 @@ fn parse_graph_node(map: &tg::value::Map) -> tg::Result<tg::graph::Node> {
 					.map_err(|_| tg::error!("expected a module kind"))?;
 				module.replace(value);
 			},
+			"size" => {
+				let value = value
+					.try_unwrap_number_ref()
+					.map_err(|_| tg::error!("expected number for size"))?;
+				size = Some(
+					value
+						.to_u64()
+						.ok_or_else(|| tg::error!("size must be a non-negative integer"))?,
+				);
+			},
 			_ => {
 				return Err(tg::error!("unexpected field in graph node: {}", key));
 			},
@@ -1196,6 +1223,7 @@ fn parse_graph_node(map: &tg::value::Map) -> tg::Result<tg::graph::Node> {
 				dependencies,
 				executable,
 				module,
+				size,
 			}))
 		},
 		"symlink" => Ok(tg::graph::Node::Symlink(tg::graph::Symlink {
diff --git a/packages/client/src/value/print.rs b/packages/client/src/value/print.rs
index b1fcc5411..81a19983a 100644
--- a/packages/client/src/value/print.rs
+++ b/packages/client/src/value/print.rs
@@ -391,6 +391,9 @@ where
 		if file.executable {
 			self.map_entry("executable", |s| s.bool(file.executable))?;
 		}
+		if let Some(size) = file.size {
+			self.map_entry("size", |s| s.number(size.to_f64().unwrap()))?;
+		}
 		if let Some(module) = &file.module {
 			self.map_entry("module", |s| s.string(&module.to_string()))?;
 		}
diff --git a/packages/clients/js/src/file.ts b/packages/clients/js/src/file.ts
index 0703783aa..7b9a27f15 100644
--- a/packages/clients/js/src/file.ts
+++ b/packages/clients/js/src/file.ts
@@ -113,7 +113,8 @@ export class File {
 		);
 		let executable = arg.executable ?? false;
 		let module = arg.module;
-		let object = { contents, dependencies, executable, module };
+		let size = arg.size ?? undefined;
+		let object = { contents, dependencies, executable, module, size };
 		return tg.File.withObject(object);
 	}
 
diff --git a/packages/clients/js/src/graph.ts b/packages/clients/js/src/graph.ts
index 18fe1df61..fb011122b 100644
--- a/packages/clients/js/src/graph.ts
+++ b/packages/clients/js/src/graph.ts
@@ -83,12 +83,14 @@ export class Graph {
 					);
 					let executable = node.executable ?? false;
 					let module = node.module ?? undefined;
+					let size = node.size ?? undefined;
 					return {
 						kind: "file" as const,
 						contents,
 						dependencies,
 						executable,
 						module,
+						size,
 					};
 				} else if (node.kind === "symlink") {
 					let artifact = tg.Graph.Edge.fromArg(node.artifact, arg.nodes);
@@ -195,6 +197,9 @@ export class Graph {
 					if ("executable" in argNode) {
 						node.executable = argNode.executable;
 					}
+					if ("size" in argNode) {
+						node.size = argNode.size;
+					}
 					nodes.push(node);
 				} else if (argNode.kind === "symlink") {
 					let artifact: tg.Graph.Arg.Edge<tg.Artifact> | undefined;
@@ -332,6 +337,7 @@ export namespace Graph {
 				| undefined;
 			executable?: boolean | undefined;
 			module?: string | undefined;
+			size?: number | undefined;
 		};
 
 		export type Symlink = {
@@ -560,6 +566,7 @@ export namespace Graph {
 		};
 		executable: boolean;
 		module: string | undefined;
+		size: number | undefined;
 	};
 
 	export namespace File {
@@ -581,6 +588,12 @@ export namespace Graph {
 			if (object.executable !== false) {
 				data.executable = object.executable;
 			}
+			if (object.module !== undefined) {
+				data.module = object.module;
+			}
+			if (object.size !== undefined) {
+				data.size = object.size;
+			}
 			return data;
 		};
 
@@ -609,6 +622,7 @@ export namespace Graph {
 				),
 				executable: data.executable ?? false,
 				module: data.module ?? undefined,
+				size: data.size ?? undefined,
 			};
 		};
 
@@ -998,6 +1012,7 @@ export namespace Graph {
 			};
 			executable?: boolean;
 			module?: string;
+			size?: number;
 		};
 
 		export type Symlink = {
diff --git a/packages/js/src/tangram.d.ts b/packages/js/src/tangram.d.ts
index 2626b188c..9d748ea34 100644
--- a/packages/js/src/tangram.d.ts
+++ b/packages/js/src/tangram.d.ts
@@ -496,6 +496,8 @@ declare namespace tg {
 					  }
 					| undefined;
 				executable?: boolean | undefined;
+				module?: string | undefined;
+				size?: number | undefined;
 			};
 
 			type Symlink = {
@@ -557,6 +559,8 @@ declare namespace tg {
 				[reference: tg.Reference]: tg.Graph.Dependency | undefined;
 			};
 			executable: boolean;
+			module: string | undefined;
+			size: number | undefined;
 		};
 
 		type Symlink = {
diff --git a/packages/server/src/checkin/artifact.rs b/packages/server/src/checkin/artifact.rs
index f07ec3a12..29157faa6 100644
--- a/packages/server/src/checkin/artifact.rs
+++ b/packages/server/src/checkin/artifact.rs
@@ -198,11 +198,18 @@ impl Server {
 					.collect::<tg::Result<_>>()?;
 				let executable = file.executable;
 				let module = file.module;
+				let size = file.size.or_else(|| {
+					file.contents.as_ref().and_then(|contents| match contents {
+						Contents::Write(output) => Some(output.length),
+						Contents::Id { .. } => None,
+					})
+				});
 				let data = tg::file::data::Node {
 					contents: Some(contents),
 					dependencies,
 					executable,
 					module,
+					size,
 				};
 				tg::file::Data::Node(data).into()
 			},
@@ -470,11 +477,18 @@ impl Server {
 					.collect::<tg::Result<_>>()?;
 				let executable = file.executable;
 				let module = file.module;
+				let size = file.size.or_else(|| {
+					file.contents.as_ref().and_then(|contents| match contents {
+						Contents::Write(output) => Some(output.length),
+						Contents::Id { .. } => None,
+					})
+				});
 				let data = tg::graph::data::File {
 					contents: Some(contents),
 					dependencies,
 					executable,
 					module,
+					size,
 				};
 				tg::graph::data::Node::File(data)
 			},
@@ -911,6 +925,12 @@ impl Server {
 					dependencies,
 					executable: file.executable,
 					module: file.module,
+					size: file.size.or_else(|| {
+						file.contents.as_ref().and_then(|contents| match contents {
+							Contents::Write(output) => Some(output.length),
+							Contents::Id { .. } => None,
+						})
+					}),
 				})
 			},
 			Variant::Directory(directory) => {
diff --git a/packages/server/src/checkin/blob.rs b/packages/server/src/checkin/blob.rs
index ffeffbcc6..508acb647 100644
--- a/packages/server/src/checkin/blob.rs
+++ b/packages/server/src/checkin/blob.rs
@@ -143,6 +143,7 @@ impl Server {
 				.unwrap()
 				.variant
 				.unwrap_file_mut();
+			file.size = Some(output.length);
 			file.contents = Some(Contents::Write(Box::new(output)));
 		}
 
diff --git a/packages/server/src/checkin/graph.rs b/packages/server/src/checkin/graph.rs
index f31def269..2f9b9ed2d 100644
--- a/packages/server/src/checkin/graph.rs
+++ b/packages/server/src/checkin/graph.rs
@@ -190,6 +190,7 @@ pub struct File {
 	pub dependencies: BTreeMap<tg::Reference, Option<tg::graph::data::Dependency>>,
 	pub executable: bool,
 	pub module: Option<tg::module::Kind>,
+	pub size: Option<u64>,
 }
 
 #[derive(Clone, Debug)]
diff --git a/packages/server/src/checkin/input.rs b/packages/server/src/checkin/input.rs
index 45e9decaa..07fed09fe 100644
--- a/packages/server/src/checkin/input.rs
+++ b/packages/server/src/checkin/input.rs
@@ -228,6 +228,7 @@ impl Server {
 				dependencies: BTreeMap::new(),
 				executable: metadata.permissions().mode() & 0o111 != 0,
 				module: None,
+				size: Some(metadata.len()),
 			})
 		} else if metadata.is_symlink() {
 			let path = std::fs::read_link(&item.path)
diff --git a/packages/server/src/checkin/lock.rs b/packages/server/src/checkin/lock.rs
index a4d4a9eaa..37c1a89d0 100644
--- a/packages/server/src/checkin/lock.rs
+++ b/packages/server/src/checkin/lock.rs
@@ -357,6 +357,7 @@ impl Server {
 						dependencies,
 						executable: file.executable,
 						module: file.module,
+						size: file.size,
 					};
 					(tg::graph::data::Node::File(data), children)
 				},
diff --git a/packages/server/src/checkin/solve.rs b/packages/server/src/checkin/solve.rs
index 803ab4f1b..0c3d2153b 100644
--- a/packages/server/src/checkin/solve.rs
+++ b/packages/server/src/checkin/solve.rs
@@ -893,11 +893,18 @@ impl Server {
 					.collect();
 				let executable = file.executable;
 				let module = file.module;
+				let size = file.size.or_else(|| {
+					contents.as_ref().and_then(|contents| match contents {
+						Contents::Write(output) => Some(output.length),
+						Contents::Id { .. } => None,
+					})
+				});
 				Variant::File(File {
 					contents,
 					dependencies,
 					executable,
 					module,
+					size,
 				})
 			},
 			tg::artifact::Data::Symlink(tg::symlink::Data::Node(symlink)) => {
@@ -1063,11 +1070,18 @@ impl Server {
 						);
 					}
 				}
+				let size = file.size.or_else(|| {
+					contents.as_ref().and_then(|contents| match contents {
+						Contents::Write(output) => Some(output.length),
+						Contents::Id { .. } => None,
+					})
+				});
 				Variant::File(File {
 					contents,
 					dependencies,
 					executable: file.executable,
 					module: file.module,
+					size,
 				})
 			},
 
diff --git a/packages/server/src/checkout/lock.rs b/packages/server/src/checkout/lock.rs
index 604292a1e..1b6224df9 100644
--- a/packages/server/src/checkout/lock.rs
+++ b/packages/server/src/checkout/lock.rs
@@ -315,6 +315,7 @@ impl Server {
 			dependencies,
 			executable: node.executable,
 			module: node.module,
+			size: node.size,
 		};
 		let node = tg::graph::data::Node::File(file);
 		Ok(node)
@@ -535,6 +536,7 @@ impl Server {
 			dependencies,
 			executable: node.executable,
 			module: node.module,
+			size: node.size,
 		};
 		let node = tg::graph::data::Node::File(file);
 		Ok(node)
diff --git a/packages/server/src/vfs/provider.rs b/packages/server/src/vfs/provider.rs
index 87b1ac6f2..75be47469 100644
--- a/packages/server/src/vfs/provider.rs
+++ b/packages/server/src/vfs/provider.rs
@@ -1036,7 +1036,9 @@ impl Provider {
 		match artifact {
 			Some(artifact) if matches!(artifact.kind(), tg::artifact::Kind::File) => {
 				let (file, _) = self.file_node_inner(artifact).await?;
-				let size = if let Some(contents) = file.contents.as_ref() {
+				let size = if let Some(size) = file.size {
+					size
+				} else if let Some(contents) = file.contents.as_ref() {
 					self.blob_length_inner(contents).await?
 				} else {
 					0
@@ -1747,9 +1749,13 @@ impl Provider {
 		match artifact {
 			Some(artifact) if matches!(artifact.kind(), tg::artifact::Kind::File) => {
 				let (file, _) = self.file_node_sync_inner(artifact, transaction)?;
-				let size = file.contents.as_ref().map_or(Ok(0), |contents| {
-					self.blob_length_sync_inner(contents, transaction)
-				})?;
+				let size = if let Some(size) = file.size {
+					size
+				} else {
+					file.contents.as_ref().map_or(Ok(0), |contents| {
+						self.blob_length_sync_inner(contents, transaction)
+					})?
+				};
 				Ok(vfs::Attrs::new(vfs::FileType::File {
 					executable: file.executable,
 					size,
diff --git a/packages/server/src/write.rs b/packages/server/src/write.rs
index e0699151f..0303f619a 100644
--- a/packages/server/src/write.rs
+++ b/packages/server/src/write.rs
@@ -73,6 +73,7 @@ impl Server {
 				dependencies: BTreeMap::new(),
 				executable: false,
 				module: None,
+				size: Some(blob.length),
 			});
 			let id = tg::file::Id::new(&data.serialize()?);
 			let path = self.cache_path().join(id.to_string());