diff --git a/CLAUDE.md b/CLAUDE.md
index ba665c7..fe92f7b 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -47,7 +47,7 @@ Transcript-based shell integration test runner. Bun + TypeScript.
   - Can appear in both `.shout` files and setup files
 - `@setup path.shout` before first command = prepend commands (and `@env`) from another file
   - Setup files use a plain format: each line is a command (no `$ ` prefix), `#` lines are comments, blank lines ignored
-  - Setup files can contain `@env` and `@teardown` directives but not `@setup` (no nesting)
+  - Setup files can contain `@env`, `@teardown`, and `@def` directives but not `@setup` (no nesting)
   - User file `@env` overrides setup file `@env`
   - Setup command failures abort the test with an error
 - `@def name body` before first command = define a macro
diff --git a/src/cli/index.ts b/src/cli/index.ts
index 9f2702e..b7da8bb 100755
--- a/src/cli/index.ts
+++ b/src/cli/index.ts
@@ -117,7 +117,8 @@ program
       const envVars: Record<string, string> = {}
       const setupEnvVars: Record<string, string> = {}
       const userEnvVars: Record<string, string> = {}
-      const macros: Record<string, string> = {}
+      const setupMacros: Record<string, string> = {}
+      const userMacros: Record<string, string> = {}
       const setupCommands: Command[] = []
       const teardownCommands: Command[] = [...parsed.teardownCommands]
       for (const d of parsed.directives) {
@@ -127,31 +128,28 @@ program
           const setupParsed = parseSetup(relative(cwd, setupPath), setupContent)
           for (const sd of setupParsed.directives) {
             if (sd.type === "env") setupEnvVars[sd.key] = sd.value
-            else if (sd.type === "def") macros[sd.name] = sd.body
+            else if (sd.type === "def") setupMacros[sd.name] = sd.body
           }
           setupCommands.push(...setupParsed.commands)
           teardownCommands.push(...setupParsed.teardownCommands)
         } else if (d.type === "env") {
           userEnvVars[d.key] = d.value
         } else if (d.type === "def") {
-          macros[d.name] = d.body
+          userMacros[d.name] = d.body
         }
       }
       Object.assign(envVars, setupEnvVars, userEnvVars)
       if (!("PORT" in userEnvVars) && !("PORT" in setupEnvVars)) {
         envVars["PORT"] = String(port)
       }
+      const macros: Record<string, string> = Object.assign({}, setupMacros, userMacros)
       const expandMacro = (cmd: Command): Command => {
         const body = macros[cmd.command]
         return body !== undefined ? { ...cmd, command: body } : cmd
       }
       const merged: ShoutFile = {
         ...parsed,
-        commands: [
-          ...setupCommands.map(expandMacro),
-          ...parsed.commands.map(expandMacro),
-          ...teardownCommands.map(expandMacro),
-        ],
+        commands: [...setupCommands, ...parsed.commands, ...teardownCommands].map(expandMacro),
       }
 
       const setupLen = setupCommands.length
diff --git a/src/parse.test.ts b/src/parse.test.ts
index f7e3c96..8c59714 100644
--- a/src/parse.test.ts
+++ b/src/parse.test.ts
@@ -236,6 +236,24 @@ describe("parse", () => {
     )
   })
 
+  test("@def trailing backslash with no continuation throws", () => {
+    expect(() => parse("test.shout", "@def foo echo a \\\n")).toThrow(
+      "test.shout:1: @def ends with \\ but has no continuation line",
+    )
+  })
+
+  test("@def continuation consuming blank line throws", () => {
+    expect(() => parse("test.shout", "@def foo echo a \\\n\n$ echo real\n")).toThrow(
+      "test.shout:2: @def continuation consumed a command or directive line",
+    )
+  })
+
+  test("@def continuation consuming comment line throws", () => {
+    expect(() => parse("test.shout", "@def foo echo a \\\n# comment\n$ echo real\n")).toThrow(
+      "test.shout:2: @def continuation consumed a command or directive line",
+    )
+  })
+
   test("@def after first command is expected output", () => {
     const result = parse("test.shout", "$ cat file\n@def foo bar\n")
     expect(result.directives).toEqual([])
diff --git a/src/parse.ts b/src/parse.ts
index 35cda7b..28a392d 100644
--- a/src/parse.ts
+++ b/src/parse.ts
@@ -77,23 +77,24 @@ function parseDefDirective(
     throw new Error(`${path}:${i + 1}: @def requires a name and body`)
   }
   const name = rest.slice(0, spaceIdx)
-  let body = rest.slice(spaceIdx + 1)
+  let body = rest.slice(spaceIdx + 1).trim()
+  if (!body) {
+    throw new Error(`${path}:${i + 1}: @def requires a name and body`)
+  }
   let extra = 0
 
-  while (body.endsWith("\\") && i + extra + 1 < rawLines.length) {
+  while (body.endsWith("\\")) {
+    if (i + extra + 1 >= rawLines.length) {
+      throw new Error(`${path}:${i + extra + 1}: @def ends with \\ but has no continuation line`)
+    }
     const next = rawLines[i + extra + 1]!
-    if (next.startsWith("$") || next.startsWith("@")) {
+    if (next.startsWith("$") || next.startsWith("@") || next.trim() === "" || next.startsWith("#")) {
       throw new Error(`${path}:${i + extra + 2}: @def continuation consumed a command or directive line`)
     }
     body = body.slice(0, -1).trimEnd() + "\n" + next.trim()
     extra++
   }
 
-  body = body.trim()
-  if (!body) {
-    throw new Error(`${path}:${i + 1}: @def requires a name and body`)
-  }
-
   return { name, body, linesConsumed: extra }
 }