diff --git a/apps/server/src/processRunner.test.ts b/apps/server/src/processRunner.test.ts
index e264ba7849da..d7f3799e103b 100644
--- a/apps/server/src/processRunner.test.ts
+++ b/apps/server/src/processRunner.test.ts
@@ -412,3 +412,11 @@ describe("isWindowsCommandNotFound", () => {
     }),
   );
 });
+
+describe("commandName", () => {
+  it("drops the directory from POSIX and Windows paths", () => {
+    expect(ProcessRunner.commandName("/Users/me/.local/bin/claude")).toBe("claude");
+    expect(ProcessRunner.commandName("C:\\Program Files\\nodejs\\npx.cmd")).toBe("npx.cmd");
+    expect(ProcessRunner.commandName("git")).toBe("git");
+  });
+});
diff --git a/apps/server/src/processRunner.ts b/apps/server/src/processRunner.ts
index 0a9bb9b04a43..36bb5b649f06 100644
--- a/apps/server/src/processRunner.ts
+++ b/apps/server/src/processRunner.ts
@@ -285,10 +285,14 @@ function finalizeRunProcess<R>(
   );
 }
 
+/** The executable name without its directory, recorded as `process.command` on process spans. */
+export const commandName = (command: string) => command.replace(/^.*[\\/]/, "");
+
 const runProcessCore = Effect.fn("processRunner.runProcessCore")(function* (
   spawner: ChildProcessSpawner.ChildProcessSpawner["Service"],
   input: ProcessRunInput,
 ): Effect.fn.Return<ProcessRunOutput, ProcessRunError, Scope.Scope> {
+  yield* Effect.annotateCurrentSpan("process.command", commandName(input.command));
   const maxOutputBytes = input.maxOutputBytes ?? DEFAULT_MAX_OUTPUT_BYTES;
   const outputMode = input.outputMode ?? "error";
   const truncatedMarker = input.truncatedMarker ?? "";