diff --git a/commands/core/utils.go b/commands/core/utils.go
index 2686175..07f895c 100644
--- a/commands/core/utils.go
+++ b/commands/core/utils.go
@@ -62,3 +62,7 @@ func hasPrefix(s, prefix string) bool {
 	}
 	return true
 }
+// CI = case insensitive
+func HasPrefixCI(s, prefix string) bool {
+	return hasPrefix(s, prefix)
+}
diff --git a/commands/fs/chmod.go b/commands/fs/chmod.go
index 6258c1e..d13c308 100644
--- a/commands/fs/chmod.go
+++ b/commands/fs/chmod.go
@@ -8,9 +8,82 @@ func init() {
 	core.Register(&core.Spec{
 		Name:        "chmod",
 		Description: "change file permissions",
-		Generator:   core.FileGenerator(),
+		MaxArgs:     2, // 1 option + 1 file
+		Subcommands: []core.Subcommand{},
 		Options: []core.Option{
-			{Name: "-R", Description: "recursive"},
+			{Name: "-R", Description: "apply recursively to directories"},
+			{Name: "--recursive", Description: "apply recursively to directories"},
+			{Name: "-v", Description: "verbose: show each file processed"},
+			{Name: "--verbose", Description: "verbose: show each file processed"},
+			{Name: "-c", Description: "like verbose but report only when a change is made"},
+			{Name: "--changes", Description: "like verbose but report only when a change is made"},
+			{Name: "-f", Description: "suppress most error messages"},
+			{Name: "--silent", Description: "suppress most error messages"},
+			{Name: "--quiet", Description: "suppress most error messages"},
+			{Name: "--reference", Description: "use another file's mode as reference (--reference=FILE)"},
+			{Name: "-H", Description: "follow symlinks on command line (use with -R)"},
+			{Name: "-L", Description: "follow all symlinks (use with -R)"},
+			{Name: "-P", Description: "do not follow any symlinks (use with -R)"},
 		},
+		Generator: modeGenerator(),
 	})
 }
+
+// modeGenerator suggests common chmod mode strings as the first argument,
+// then falls back to file suggestions for subsequent arguments
+func modeGenerator() core.GeneratorFunc {
+	filegen := core.FileGenerator(".sh", ".py", ".bin", ".run")
+
+	commonModes := []struct {
+		mode string
+		desc string
+	}{
+		{"+x", "add execute for all"},
+		{"-x", "remove execute for all"},
+		{"u+x", "add execute for owner"},
+		{"a+x", "add execute for all (explicit)"},
+
+		{"u+rw", "owner read+write"},
+		{"go-w", "remove write from group+others"},
+		{"a-w", "remove write from everyone"},
+		{"u+s", "set SUID bit"},
+		{"g+s", "set SGID bit"},
+		{"+t", "set sticky bit"},
+
+		{"755", "rwxr-xr-x (executable/dir, world-readable)"},
+		{"644", "rw-r--r-- (regular file, world-readable)"},
+		{"600", "rw------- (private file)"},
+		{"700", "rwx------ (private executable)"},
+		{"777", "rwxrwxrwx (full permissions for all)"},
+		{"666", "rw-rw-rw- (read+write for all)"},
+		{"400", "r-------- (read-only for owner)"},
+		{"444", "r--r--r-- (read-only for all)"},
+		{"750", "rwxr-x--- (group can read+execute)"},
+		{"640", "rw-r----- (group can read)"},
+		{"664", "rw-rw-r-- (group can read+write)"},
+	}
+
+	return func(tokens []string, prefix string, partial string) []core.Suggestion {
+		argCount := 0
+		for i := 1; i < len(tokens); i++ {
+			t := tokens[i]
+			if t != "" && t[0] != '-' {
+				argCount++
+			}
+		}
+
+		if argCount == 0 {
+			var results []core.Suggestion
+			for _, m := range commonModes {
+				if partial == "" || core.HasPrefixCI(m.mode, partial) {
+					results = append(results, core.Suggestion{
+						Cmd:  m.mode,
+						Desc: m.desc,
+					})
+				}
+			}
+			return results
+		}
+		return filegen(tokens, prefix, partial)
+	}
+}