fix: dedupe repeated skill_discovered events

packages/cli/src/tool/skill.ts

@@ -9,21 +9,30 @@ import { iife } from "@/util/iife"
 import { Plugin } from "../plugin"
 import { Bus } from "../bus"
 import { Session } from "../session"
+import { Instance } from "../project/instance"
 
-export const SkillTool = Tool.define("skill", async (ctx) => {
-  const skills = await Skill.all()
+const discovered = Instance.state(() => new Set<string>())
 
-  // Emit per-skill discovery events when descriptions are registered in tool schema
-  if (ctx?.sessionID) {
-    for (const skill of skills) {
-      Bus.publish(Session.Event.SkillDiscovered, {
-        sessionID: ctx.sessionID,
-        name: skill.name,
-        description: skill.description,
-        location: skill.location,
-      })
-    }
+function publish(ctx?: Tool.InitContext, skills?: Awaited<ReturnType<typeof Skill.all>>) {
+  if (!ctx?.sessionID || !skills?.length) return
+
+  const seen = discovered()
+  for (const skill of skills) {
+    const key = `${ctx.sessionID}:${skill.name}`
+    if (seen.has(key)) continue
+    seen.add(key)
+    Bus.publish(Session.Event.SkillDiscovered, {
+      sessionID: ctx.sessionID,
+      name: skill.name,
+      description: skill.description,
+      location: skill.location,
+    })
   }
+}
+
+export const SkillTool = Tool.define("skill", async (ctx) => {
+  const skills = await Skill.all()
+  publish(ctx, skills)
 
   // Filter skills by agent permissions if agent provided
   const agent = ctx?.agent

packages/cli/test/tool/skill-events.test.ts

@@ -25,7 +25,7 @@ const noopCtx: Tool.Context = {
 }
 
 describe("skill events", () => {
-  test("SkillDiscovered emitted per skill on init with sessionID", async () => {
+  test("SkillDiscovered emitted once per skill for a session", async () => {
     await using tmp = await tmpdir({
       git: true,
       init: async (dir) => {
@@ -66,6 +66,7 @@ description: Second skill.
             events.push(evt.properties)
           })
 
+          await SkillTool.init({ sessionID: "test-session" })
           await SkillTool.init({ sessionID: "test-session" })
 
           unsub()
@@ -126,6 +127,51 @@ description: A skill.
     }
   })
 
+  test("SkillDiscovered emitted again for a different session", async () => {
+    await using tmp = await tmpdir({
+      git: true,
+      init: async (dir) => {
+        const skillDir = path.join(dir, ".aictrl", "skill", "gamma")
+        await Bun.write(
+          path.join(skillDir, "SKILL.md"),
+          `---
+name: gamma
+description: A skill.
+---
+
+# Gamma
+`,
+        )
+      },
+    })
+
+    const home = process.env.AICTRL_TEST_HOME
+    process.env.AICTRL_TEST_HOME = tmp.path
+
+    try {
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const events: Array<{ name: string; sessionID: string }> = []
+          const unsub = Bus.subscribe(Session.Event.SkillDiscovered, (evt) => {
+            events.push(evt.properties)
+          })
+
+          await SkillTool.init({ sessionID: "session-a" })
+          await SkillTool.init({ sessionID: "session-b" })
+
+          unsub()
+
+          expect(events.length).toBe(2)
+          expect(events.map((evt) => evt.sessionID).sort()).toEqual(["session-a", "session-b"])
+          expect(events.every((evt) => evt.name === "gamma")).toBe(true)
+        },
+      })
+    } finally {
+      process.env.AICTRL_TEST_HOME = home
+    }
+  })
+
   test("SkillLoaded emitted when skill tool is executed", async () => {
     await using tmp = await tmpdir({
       git: true,