diff --git a/crates/cli/Cargo.toml b/crates/cli/Cargo.toml
index 453467d7..6e3cf793 100644
--- a/crates/cli/Cargo.toml
+++ b/crates/cli/Cargo.toml
@@ -40,10 +40,13 @@ termcolor = "1.4.0"
 tracing = "0.1.40"
 which = "5.0.0"
 
-[dev-dependencies]
-tracing-test = "0.1"
-uuid = { workspace = true, features = [ "v4", "fast-rng" ] }
-rand = { workspace = true }
+[dependencies.blake3]
+version = "1.3.3"
+features = ["rayon"]
+
+[dependencies.command-group]
+version = "2.1.0"
+features = ["with-tokio"]
 
 [dependencies.clap]
 version = "4.4.7"
@@ -123,6 +126,11 @@ embed-resource = "2.4.0"
 version = "1.0.2"
 path = "../bosion"
 
+[dev-dependencies]
+tracing-test = "0.1"
+uuid = { workspace = true, features = [ "v4", "fast-rng" ] }
+rand = { workspace = true }
+
 [features]
 default = ["pid1"]
 
diff --git a/crates/cli/src/args.rs b/crates/cli/src/args.rs
index 6a162954..8f5bc70f 100644
--- a/crates/cli/src/args.rs
+++ b/crates/cli/src/args.rs
@@ -808,7 +808,7 @@ pub struct Args {
 	///     If the file is smaller than n bytes, the whole file is returned. There is no filter to
 	///     read the whole file at once to encourage limiting the amount of data read and processed.
 	///
-	///   - 'string | hash', and 'path | hashfile' return the hash of the string or file at path.
+	///   - 'string | hash', and 'path | file_hash' return the hash of the string or file at path.
 	///     No guarantee is made about the algorithm used: treat it as an opaque value.
 	///
 	///   - 'any | kv_store(key)', 'kv_fetch(key)', and 'kv_clear' provide a simple key-value store.
@@ -826,7 +826,9 @@ pub struct Args {
 	/// the path to a file containing a jaq program.
 	///
 	/// Jaq programs are run in order, after all other filters, and short-circuit: if a filter (jaq
-	/// or not) rejects an event, execution stops there, and no other filters are run.
+	/// or not) rejects an event, execution stops there, and no other filters are run. Additionally,
+	/// they stop after outputting the first value, so you'll want to use 'any' or 'all' when
+	/// iterating, otherwise only the first item will be processed, which can be quite confusing!
 	///
 	/// Examples:
 	///
diff --git a/crates/cli/src/filterer/proglib.rs b/crates/cli/src/filterer/proglib.rs
index cc86347e..16c1f9a9 100644
--- a/crates/cli/src/filterer/proglib.rs
+++ b/crates/cli/src/filterer/proglib.rs
@@ -270,6 +270,58 @@ pub fn load_watchexec_defs(defs: &mut Definitions) -> miette::Result<()> {
 		}),
 	);
 
+	trace!("jaq: add hash filter");
+	defs.insert_custom(
+		"hash",
+		CustomFilter::new(0, {
+			move |_, (_, val)| {
+				let string = match &val {
+					Val::Str(v) => v.to_string(),
+					_ => return_err!(custom_err("expected string but got {val:?}")),
+				};
+
+				Box::new(once(Ok(Val::Str(
+					blake3::hash(string.as_bytes()).to_hex().to_string().into(),
+				))))
+			}
+		}),
+	);
+
+	trace!("jaq: add file_hash filter");
+	defs.insert_custom(
+		"file_hash",
+		CustomFilter::new(0, {
+			move |_, (_, val)| {
+				let path = match &val {
+					Val::Str(v) => v.to_string(),
+					_ => return_err!(custom_err("expected string but got {val:?}")),
+				};
+
+				Box::new(once(Ok(match File::open(&path) {
+					Ok(mut file) => {
+						const BUFFER_SIZE: usize = 1024 * 1024;
+						let mut hasher = blake3::Hasher::new();
+						let mut buf = vec![0; BUFFER_SIZE];
+						while let Ok(bytes) = file.read(&mut buf) {
+							debug!("jaq: read {bytes} bytes from {path:?}");
+							if bytes == 0 {
+								break;
+							}
+							hasher.update(&buf[..bytes]);
+							buf = vec![0; BUFFER_SIZE];
+						}
+
+						Val::Str(hasher.finalize().to_hex().to_string().into())
+					}
+					Err(err) => {
+						error!("jaq: failed to open file {path:?}: {err:?}");
+						Val::Null
+					}
+				})))
+			}
+		}),
+	);
+
 	Ok(())
 }