fix(tui): insert skill name without wiping existing prompt text

packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx

@@ -587,12 +587,9 @@ export function Prompt(props: PromptProps) {
           dialog.replace(() => (
             <DialogSkill
               onSelect={(skill) => {
-                input.setText(`/${skill} `)
-                setStore("prompt", {
-                  input: `/${skill} `,
-                  parts: [],
-                })
-                input.gotoBufferEnd()
+                input.insertText(`/${skill} `)
+                setStore("prompt", "input", input.plainText)
+                syncExtmarksWithPromptParts()
               }}
             />
           ))

packages/opencode/test/cli/tui/prompt-skill-select.test.ts

@@ -0,0 +1,106 @@
+import { describe, expect, test } from "bun:test"
+
+// Regression test for the DialogSkill onSelect handler in
+// packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx.
+//
+// Before the fix, onSelect called `input.setText(`/${skill} `)` which
+// replaced the entire prompt content, wiping any text the user had already
+// typed. After the fix, it calls `input.insertText(`/${skill} `)` which
+// inserts at the cursor position, preserving existing text.
+//
+// `handleSkillSelect` below has the exact shape of the production handler after
+// the fix.
+
+type TextInput = {
+  plainText: string
+  insertText(text: string): void
+}
+
+type Store = {
+  prompt: { input: string; parts: unknown[] }
+  extmarkToPartIndex: Map<number, number>
+}
+
+function makeMockInput(initialText: string, cursorOffset: number): TextInput & { cursorOffset: number } {
+  let text = initialText
+  let cursor = cursorOffset
+  return {
+    get plainText() { return text },
+    get cursorOffset() { return cursor },
+    insertText(insert: string) {
+      text = text.slice(0, cursor) + insert + text.slice(cursor)
+      cursor += insert.length
+    },
+  }
+}
+
+function handleSkillSelect(input: TextInput, store: Store, syncExtmarks: () => void, skill: string) {
+  input.insertText(`/${skill} `)
+  store.prompt.input = input.plainText
+  syncExtmarks()
+}
+
+describe("Prompt skill picker onSelect", () => {
+  test("inserts skill name without wiping existing prompt text", () => {
+    const input = makeMockInput("some existing text", 18)
+    const store: Store = {
+      prompt: { input: "some existing text", parts: [] },
+      extmarkToPartIndex: new Map(),
+    }
+    let synced = false
+
+    handleSkillSelect(input, store, () => { synced = true }, "test-skill")
+
+    expect(input.plainText).toBe("some existing text/test-skill ")
+    expect(store.prompt.input).toBe("some existing text/test-skill ")
+    expect(store.prompt.parts).toEqual([])
+    expect(synced).toBe(true)
+  })
+
+  test("inserts skill name at cursor position when cursor is at start", () => {
+    const input = makeMockInput("existing question here?", 0)
+    const store: Store = {
+      prompt: { input: "existing question here?", parts: [] },
+      extmarkToPartIndex: new Map(),
+    }
+    let synced = false
+
+    handleSkillSelect(input, store, () => { synced = true }, "test-skill")
+
+    expect(input.plainText).toBe("/test-skill existing question here?")
+    expect(store.prompt.input).toBe("/test-skill existing question here?")
+    expect(synced).toBe(true)
+  })
+
+  test("inserts skill name at cursor position mid-text", () => {
+    const input = makeMockInput("hello world", 5)
+    const store: Store = {
+      prompt: { input: "hello world", parts: [] },
+      extmarkToPartIndex: new Map(),
+    }
+    let synced = false
+
+    handleSkillSelect(input, store, () => { synced = true }, "my-skill")
+
+    expect(input.plainText).toBe("hello/my-skill  world")
+    expect(store.prompt.input).toBe("hello/my-skill  world")
+    expect(synced).toBe(true)
+  })
+
+  test("inserts skill name into empty prompt", () => {
+    const input = makeMockInput("", 0)
+    const store: Store = {
+      prompt: { input: "", parts: [] },
+      extmarkToPartIndex: new Map(),
+    }
+    let synced = false
+
+    handleSkillSelect(input, store, () => { synced = true }, "my-skill")
+
+    expect(input.plainText).toBe("/my-skill ")
+    expect(store.prompt.input).toBe("/my-skill ")
+    expect(synced).toBe(true)
+  })
+})
+
+