diff --git a/src/detect.ts b/src/detect.ts
new file mode 100644
index 0000000..a7401d6
--- /dev/null
+++ b/src/detect.ts
@@ -0,0 +1,8 @@
+/** Raw `/skill:name` at start of user input (SPEC §6.2 #1). */
+const SLASH_SKILL_RE = /^\/skill:([a-z0-9-]+)/;
+
+/** Returns skill name when text is a slash skill command, else null. */
+export function detectSlashSkill(text: string): string | null {
+	const match = SLASH_SKILL_RE.exec(text);
+	return match?.[1] ?? null;
+}