fix(ai-sessions): keep the refused prompt, the deleted chat and the mid-load artifact list

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/src/lib/components/copilot/chat/AIChatManager.svelte.ts

@@ -1962,8 +1962,13 @@ export class AIChatManager {
 		// A synthetic send carries none of the user's text; its caller owns the
 		// instructions it set and unwinds them itself.
 		if (options.synthetic || options.queued) return
+		// The same fallback sendRequestImpl applies: the programmatic senders (an
+		// editor's AI Fix, Ask AI) leave the prompt on `this.instructions` and pass
+		// no `instructions` option, so reading the option alone would hand back an
+		// empty prompt and lose what they were about to send.
+		const instructions = options.instructions ?? this.instructions
 		const restored = this.aiChatInput?.restoreInstructions(
-			options.instructions ?? '',
+			instructions,
 			options.pastes ?? [],
 			options.images ?? [],
 			options.files ?? []
@@ -1972,9 +1977,9 @@ export class AIChatManager {
 		// queue so it is still the user's to send rather than silently gone. The
 		// queue holds plain text, so the pastes are expanded into it — parked as
 		// bare tokens they would point at blobs nothing holds any more.
-		if (restored !== true && options.instructions) {
+		if (restored !== true && instructions) {
 			this.restoreToInput(
-				expanded(chatDraft(options.instructions, options.pastes ?? [])),
+				expanded(chatDraft(instructions, options.pastes ?? [])),
 				options.images,
 				options.files
 			)

frontend/src/lib/components/copilot/chat/HistoryManager.svelte.ts

@@ -618,7 +618,14 @@ export default class HistoryManager {
 		if (!db) return 'unavailable'
 		try {
 			const chat = await db.get('chats', id)
-			if (!chat) return 'missing'
+			if (!chat) {
+				// Drop the mirror too. `loadPastChat` reads from it and never from the
+				// store, so a copy left behind here is a deleted chat that comes back
+				// on the next rotation onto this id.
+				const { [id]: _gone, ...rest } = this.savedChats
+				this.savedChats = rest
+				return 'missing'
+			}
 			this.savedChats = { ...this.savedChats, [id]: chat }
 			return 'loaded'
 		} catch (err) {

frontend/src/lib/components/copilot/chat/HistoryManager.test.ts

@@ -810,6 +810,25 @@ describe('HistoryManager.reloadChat', () => {
 		expect(await hm.reloadChat('no-such-chat')).toBe('missing')
 	})
 
+	it('evicts the mirrored copy of a chat the driver deleted', async () => {
+		const hm = new HistoryManager()
+		await hm.init()
+		const chatId = hm.getCurrentChatId()
+		await hm.saveChat(
+			[{ role: 'user', content: 'deleted by the driving tab' }] as DisplayMessage[],
+			[] as ChatCompletionMessageParam[]
+		)
+
+		const db = await openDB('copilot-chat-history::admin@test')
+		await db.delete('chats' as never, chatId)
+		db.close()
+
+		expect(await hm.reloadChat(chatId)).toBe('missing')
+		// loadPastChat serves the mirror, so a copy left behind would resurrect the
+		// deleted transcript the next time this id came round again.
+		expect(await hm.loadPastChat(chatId)).toBeUndefined()
+	})
+
 	it('reports a store it cannot open as unavailable, never as missing', async () => {
 		;(globalThis as any).indexedDB = {
 			open: () => {

frontend/src/lib/components/copilot/chat/artifacts/artifactsState.svelte.ts

@@ -154,6 +154,11 @@ export class SessionArtifactsStore {
 		// previous one's row placed into its list, nor one of its own rows dropped.
 		if (this.#sessionId !== loaded) return
 		if (read.state === 'unavailable') return
+		// Sampled after the awaits, once a load racing us may already have landed.
+		// A write below both derives from a list that load has not filled yet and
+		// bumps the token it checks on arrival, so it would leave this session
+		// holding only what this notification carried until the next write.
+		const loadInFlight = this.loading
 		if (read.state === 'loaded') {
 			// Weighed against what is held, not placed over it: an ordinary artifact
 			// whose persist the store refused lives only in memory here, and taking
@@ -161,10 +166,13 @@ export class SessionArtifactsStore {
 			// a different one.
 			const held = this.artifacts.find((a) => a.id === artifactId)
 			this.#place(furtherAlong(read.artifact, held) ?? read.artifact)
+			if (loadInFlight) await this.#load()
 			return
 		}
 		const next = this.artifacts.filter((a) => a.id !== artifactId)
-		if (next.length !== this.artifacts.length) this.#applyWrite(next)
+		if (next.length === this.artifacts.length) return
+		this.#applyWrite(next)
+		if (loadInFlight) await this.#load()
 	}
 
 	async get(id: string): Promise<PersistedArtifact | undefined> {

frontend/src/lib/components/copilot/chat/artifacts/artifactsState.test.ts

@@ -588,6 +588,29 @@ describe('cross-tab artifact sync', () => {
 		expect(broadcasts).toEqual([])
 	})
 
+	// A tab opening the session reads the whole list; a notification landing inside that read
+	// writes from the list it has so far — empty — and invalidates the read on its way out.
+	it('keeps the rest of the session when a notification lands mid-load', async () => {
+		const kept = await store.create('s1', { name: 'Plan', content: 'p' })
+		const notified = await store.create('s1', { name: 'Notes', content: 'n' })
+
+		const opening = new stateMod.SessionArtifactsStore()
+		let release: () => void = () => {}
+		const held = new Promise<void>((r) => (release = r))
+		const listForSession = dbMod.listArtifactsForSession
+		vi.spyOn(dbMod, 'listArtifactsForSession').mockImplementationOnce(async (id: string) => {
+			await held
+			return listForSession(id)
+		})
+
+		const loading = opening.setSession('s1')
+		await opening.applyRemoteArtifact(notified.id)
+		release()
+		await loading
+
+		expect(opening.artifacts.map((a) => a.id).sort()).toEqual([kept.id, notified.id].sort())
+	})
+
 	it('drops an artifact the other tab removed', async () => {
 		const created = await store.create('s1', { name: 'Notes', content: 'x' })
 		await watcher.applyRemoteArtifact(created.id)