diff --git a/interp/builtins/break/break.go b/interp/builtins/break/break.go
index 627b9183..05e9de23 100644
--- a/interp/builtins/break/break.go
+++ b/interp/builtins/break/break.go
@@ -3,6 +3,19 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2026-present Datadog, Inc.
 
+// Package breakcmd implements the break builtin command.
+//
+// break — exit from a for, while, or until loop
+//
+// Usage: break [N]
+//
+// Exit from the innermost enclosing loop. If N is specified,
+// break out of N enclosing loops.
+//
+// Exit codes:
+//
+//	0  Loop exited successfully.
+//	1  Not inside a loop, or invalid argument.
 package breakcmd
 
 import (
diff --git a/interp/builtins/cat/cat.go b/interp/builtins/cat/cat.go
index b1eb1727..2a759e22 100644
--- a/interp/builtins/cat/cat.go
+++ b/interp/builtins/cat/cat.go
@@ -3,6 +3,19 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2026-present Datadog, Inc.
 
+// Package cat implements the cat builtin command.
+//
+// cat — concatenate and print files
+//
+// Usage: cat [FILE]...
+//
+// Concatenate FILE(s) to standard output.
+// With no FILE, or when FILE is -, read standard input.
+//
+// Exit codes:
+//
+//	0  All files processed successfully.
+//	1  At least one error occurred (missing file, permission denied, etc.).
 package cat
 
 import (
diff --git a/interp/builtins/continue/continue.go b/interp/builtins/continue/continue.go
index 0d09c19d..1a9bd5b7 100644
--- a/interp/builtins/continue/continue.go
+++ b/interp/builtins/continue/continue.go
@@ -3,6 +3,19 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2026-present Datadog, Inc.
 
+// Package continuecmd implements the continue builtin command.
+//
+// continue — resume the next iteration of a for, while, or until loop
+//
+// Usage: continue [N]
+//
+// Resume the next iteration of the innermost enclosing loop. If N is
+// specified, resume the Nth enclosing loop.
+//
+// Exit codes:
+//
+//	0  Iteration resumed successfully.
+//	1  Not inside a loop, or invalid argument.
 package continuecmd
 
 import (
diff --git a/interp/builtins/echo/echo.go b/interp/builtins/echo/echo.go
index baa98927..aec00a42 100644
--- a/interp/builtins/echo/echo.go
+++ b/interp/builtins/echo/echo.go
@@ -3,6 +3,18 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2026-present Datadog, Inc.
 
+// Package echo implements the echo builtin command.
+//
+// echo — write arguments to standard output
+//
+// Usage: echo [ARG]...
+//
+// Write each ARG to standard output, separated by a single space,
+// followed by a newline.
+//
+// Exit codes:
+//
+//	0  Always succeeds.
 package echo
 
 import (
diff --git a/interp/builtins/exit/exit.go b/interp/builtins/exit/exit.go
index 38dc9f15..e92773f1 100644
--- a/interp/builtins/exit/exit.go
+++ b/interp/builtins/exit/exit.go
@@ -3,6 +3,21 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2026-present Datadog, Inc.
 
+// Package exit implements the exit builtin command.
+//
+// exit — cause the shell to exit
+//
+// Usage: exit [N]
+//
+// Exit the shell with status N. If N is omitted, the exit status is
+// that of the last command executed. If N is not a valid integer, the
+// shell prints an error and exits with status 2.
+//
+// Exit codes:
+//
+//	N    The supplied exit status (truncated to uint8).
+//	2    Invalid (non-numeric) argument.
+//	1    Too many arguments.
 package exit
 
 import (
diff --git a/interp/builtins/false/false.go b/interp/builtins/false/false.go
index 9c96131e..5da47962 100644
--- a/interp/builtins/false/false.go
+++ b/interp/builtins/false/false.go
@@ -3,6 +3,17 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2026-present Datadog, Inc.
 
+// Package falsecmd implements the false builtin command.
+//
+// false — return an unsuccessful exit status
+//
+// Usage: false
+//
+// Do nothing and return an exit status of 1. All arguments are ignored.
+//
+// Exit codes:
+//
+//	1  Always fails.
 package falsecmd
 
 import (
diff --git a/interp/builtins/true/true.go b/interp/builtins/true/true.go
index 2bc1a04e..8908f9df 100644
--- a/interp/builtins/true/true.go
+++ b/interp/builtins/true/true.go
@@ -3,6 +3,17 @@
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
 // Copyright 2026-present Datadog, Inc.
 
+// Package truecmd implements the true builtin command.
+//
+// true — return a successful exit status
+//
+// Usage: true
+//
+// Do nothing and return an exit status of 0. All arguments are ignored.
+//
+// Exit codes:
+//
+//	0  Always succeeds.
 package truecmd
 
 import (