feat: let a text switch one thread between Claude and Codex

Review threads live on the whole diff, not on one commit, so none are shown here - a thread's line means something in the branch's final form, and painting it into an intermediate step would put it on code it is not about.

app/Models/Conversation.tsmodified+12-0

Changes to app/Models/Conversation.ts

		⋯69 linesShow the 69 lines above this hunk@@ -70,5 +70,17 @@ export default defineModel({
70	70	validation: { rule: schema.string() },
71	71	factory: () => '',
72	72	},
	73	+
	74	+ /**
	75	+ * The engine this thread was switched to, or null to follow whatever the
	76	+ * installation is set to. Null is the point: a thread that never asked
	77	+ * keeps tracking the menubar's picker, so changing it there still works.
	78	+ */
	79	+ engine: {
	80	+ order: 8,
	81	+ fillable: true,
	82	+ validation: { rule: schema.enum(['claude', 'codex']) },
	83	+ factory: () => 'claude',
	84	+ },
73	85	},
74	86	} as const)

app/Models/Run.tsmodified+12-0

Changes to app/Models/Run.ts

		⋯109 linesShow the 109 lines above this hunk@@ -110,5 +110,17 @@ export default defineModel({
110	110	validation: { rule: schema.number() },
111	111	factory: () => Date.now(),
112	112	},
	113	+
	114	+ /**
	115	+ * Which agent answered. Nullable rather than defaulted: rows written
	116	+ * before a thread could choose predate the question, and calling them all
	117	+ * Claude would be a guess recorded as a fact.
	118	+ */
	119	+ engine: {
	120	+ order: 14,
	121	+ fillable: true,
	122	+ validation: { rule: schema.enum(['claude', 'codex']) },
	123	+ factory: faker => faker.helpers.arrayElement(['claude', 'codex']),
	124	+ },
113	125	},
114	126	} as const)

app/Uplink/model-store.tsmodified+2-0

Changes to app/Uplink/model-store.ts

		⋯37 linesShow the 37 lines above this hunk@@ -38,6 +38,7 @@ export class ModelStore implements Store {
38	38	cwd: row.cwd ?? null,
39	39	lastActiveAt: row.last_active_at ?? null,
40	40	moreText: row.more_text ?? null,
	41	+ engine: row.engine ?? null,
41	42	}
42	43	}
43	44
		⋯5 linesShow the 5 lines above this hunk@@ -49,6 +50,7 @@ export class ModelStore implements Store {
49	50	cwd: conversation.cwd,
50	51	lastActiveAt: conversation.lastActiveAt,
51	52	moreText: conversation.moreText,
	53	+ engine: conversation.engine,
52	54	}
53	55	const existing = await Conversation.where('chat_guid', conversation.chatGuid).first() as { update: (v: object) => Promise<unknown> } | undefined
54	56	if (existing)

app/Uplink/sqlite-store.tsmodified+11-5

Changes to app/Uplink/sqlite-store.ts

		⋯36 linesShow the 36 lines above this hunk@@ -37,7 +37,7 @@ export interface RunRow extends RunRecord {
37	37	* old it is, and so the day a change needs more than a new column - a backfill,
38	38	* a rename - has a version to key off.
39	39	*/
40		-const SCHEMA_VERSION = 1
	40	+const SCHEMA_VERSION = 2
41	41
42	42	export interface TableSpec {
43	43	name: string
		⋯34 linesShow the 34 lines above this hunk@@ -78,6 +78,7 @@ export const TABLES: TableSpec[] = [
78	78	cwd: 'TEXT',
79	79	last_active_at: 'INTEGER',
80	80	more_text: 'TEXT',
	81	+ engine: 'TEXT',
81	82	},
82	83	},
83	84	{
		⋯13 linesShow the 13 lines above this hunk@@ -97,6 +98,7 @@ export const TABLES: TableSpec[] = [
97	98	last_activity: 'TEXT',
98	99	started_at: 'INTEGER',
99	100	finished_at: 'INTEGER',
	101	+ engine: 'TEXT',
100	102	},
101	103	},
102	104	]
		⋯12 linesShow the 12 lines above this hunk@@ -115,6 +117,7 @@ export const RUN_COLUMNS: Record<keyof RunRecord, string> = {
115	117	lastActivity: 'last_activity',
116	118	startedAt: 'started_at',
117	119	finishedAt: 'finished_at',
	120	+ engine: 'engine',
118	121	}
119	122
120	123	/**
		⋯115 linesShow the 115 lines above this hunk@@ -236,17 +239,19 @@ export class SqliteStore implements Store {
236	239	cwd: row.cwd,
237	240	lastActiveAt: row.last_active_at,
238	241	moreText: row.more_text,
	242	+ engine: row.engine,
239	243	}
240	244	}
241	245
242	246	async saveConversation(c: ConversationRecord): Promise<void> {
243	247	this.db.query(`
244		- INSERT INTO conversations (chat_guid, handle, service, session_id, cwd, last_active_at, more_text)
245		- VALUES (?, ?, ?, ?, ?, ?, ?)
	248	+ INSERT INTO conversations (chat_guid, handle, service, session_id, cwd, last_active_at, more_text, engine)
	249	+ VALUES (?, ?, ?, ?, ?, ?, ?, ?)
246	250	ON CONFLICT(chat_guid) DO UPDATE SET
247	251	handle = excluded.handle, service = excluded.service, session_id = excluded.session_id,
248		- cwd = excluded.cwd, last_active_at = excluded.last_active_at, more_text = excluded.more_text
249		- `).run(c.chatGuid, c.handle, c.service, c.sessionId, c.cwd, c.lastActiveAt, c.moreText)
	252	+ cwd = excluded.cwd, last_active_at = excluded.last_active_at, more_text = excluded.more_text,
	253	+ engine = excluded.engine
	254	+ `).run(c.chatGuid, c.handle, c.service, c.sessionId, c.cwd, c.lastActiveAt, c.moreText, c.engine)
250	255	}
251	256
252	257	async createRun(run: RunRecord): Promise<number> {
		⋯30 linesShow the 30 lines above this hunk@@ -283,6 +288,7 @@ export class SqliteStore implements Store {
283	288	lastActivity: row.last_activity,
284	289	startedAt: row.started_at,
285	290	finishedAt: row.finished_at,
	291	+ engine: row.engine,
286	292	}))
287	293	}
288	294	}

app/Uplink/store.tsmodified+10-0

Changes to app/Uplink/store.ts

		⋯3 linesShow the 3 lines above this hunk@@ -4,6 +4,8 @@
4	4	* the model-backed store in `model-store.ts`, tests use `MemoryStore`.
5	5	*/
6	6
	7	+import type { EngineId } from './engine'
	8	+
7	9	export type RunStatus = 'queued' | 'running' | 'done' | 'failed' | 'stopped'
8	10
9	11	export interface ConversationRecord {
		⋯5 linesShow the 5 lines above this hunk@@ -15,6 +17,12 @@ export interface ConversationRecord {
15	17	lastActiveAt: number | null
16	18	/** The unsent tail of the last long reply, released by "more". */
17	19	moreText: string | null
	20	+ /**
	21	+ * The engine this thread was switched to, or null to follow the
	22	+ * installation's setting. Null rather than a default so a thread that never
	23	+ * asked still tracks the menubar's picker.
	24	+ */
	25	+ engine: EngineId | null
18	26	}
19	27
20	28	export interface RunRecord {
		⋯10 linesShow the 10 lines above this hunk@@ -31,6 +39,8 @@ export interface RunRecord {
31	39	lastActivity?: string | null
32	40	startedAt?: number | null
33	41	finishedAt?: number | null
	42	+ /** Which agent answered, recorded per run because a thread can switch. */
	43	+ engine?: EngineId | null
34	44	}
35	45
36	46	export interface Store {

app/Uplink/uplink.tsmodified+1-0

Changes to app/Uplink/uplink.ts

		⋯300 linesShow the 300 lines above this hunk@@ -301,6 +301,7 @@ export class Uplink {
301	301	cwd: null,
302	302	lastActiveAt: null,
303	303	moreText: null,
	304	+ engine: null,
304	305	}
305	306	}
306	307

database/migrations/1789486698560-alter-conversations-columns.sqladded+3-0

Changes to database/migrations/1789486698560-alter-conversations-columns.sql

		@@ -0,0 +1,3 @@
	1	+-- qb:generated
	2	+-- @generated by `buddy migrate:regenerate` - edits will be overwritten
	3	+ALTER TABLE "conversations" ADD COLUMN "engine" TEXT CHECK ("engine" IN ('claude', 'codex'));

database/migrations/1789486698561-alter-runs-columns.sqladded+3-0

Changes to database/migrations/1789486698561-alter-runs-columns.sql

		@@ -0,0 +1,3 @@
	1	+-- qb:generated
	2	+-- @generated by `buddy migrate:regenerate` - edits will be overwritten
	3	+ALTER TABLE "runs" ADD COLUMN "engine" TEXT CHECK ("engine" IN ('claude', 'codex'));

storage/framework/database/model-snapshot.sqlite.jsonmodified+26-2

Changes to storage/framework/database/model-snapshot.sqlite.json

		⋯89 linesShow the 89 lines above this hunk@@ -90,6 +90,18 @@
90	90	"isUnique": false,
91	91	"isNullable": true,
92	92	"hasDefault": false
	93	+ },
	94	+ {
	95	+ "name": "engine",
	96	+ "type": "enum",
	97	+ "isPrimaryKey": false,
	98	+ "isUnique": false,
	99	+ "isNullable": true,
	100	+ "hasDefault": false,
	101	+ "enumValues": [
	102	+ "claude",
	103	+ "codex"
	104	+ ]
93	105	}
94	106	],
95	107	"indexes": [
		⋯161 linesShow the 161 lines above this hunk@@ -257,6 +269,18 @@
257	269	"isUnique": false,
258	270	"isNullable": true,
259	271	"hasDefault": false
	272	+ },
	273	+ {
	274	+ "name": "engine",
	275	+ "type": "enum",
	276	+ "isPrimaryKey": false,
	277	+ "isUnique": false,
	278	+ "isNullable": true,
	279	+ "hasDefault": false,
	280	+ "enumValues": [
	281	+ "claude",
	282	+ "codex"
	283	+ ]
260	284	}
261	285	],
262	286	"indexes": []
		⋯129 linesShow the 129 lines above this hunk@@ -392,7 +416,7 @@
392	416	}
393	417	]
394	418	},
395		- "hash": "cf904d0837380746ef9f95409635f2960b57dbac539b69229ea1da12f911d4b5",
	419	+ "hash": "3273a7f2b7ad412f972eb4decd23ad15b2cb9ac86d757bd5f520ed81f2e3d919",
396	420	"dialect": "sqlite",
397		- "updatedAt": "2026-09-28T21:27:50.923Z"
	421	+ "updatedAt": "2026-09-29T15:42:55.226Z"
398	422	}

tests/unit/uplink/sqlite-store.test.tsmodified+1-1

Changes to tests/unit/uplink/sqlite-store.test.ts

		⋯29 linesShow the 29 lines above this hunk@@ -30,7 +30,7 @@ describe('SqliteStore', () => {
30	30	await store.setCursor(42)
31	31	expect(await store.cursor()).toBe(42)
32	32
33		- const conversation = { chatGuid: 'g', handle: ME, service: 'iMessage', sessionId: 's', cwd: '/tmp', lastActiveAt: 5, moreText: 'x'.repeat(3000) }
	33	+ const conversation = { chatGuid: 'g', handle: ME, service: 'iMessage', sessionId: 's', cwd: '/tmp', lastActiveAt: 5, moreText: 'x'.repeat(3000), engine: null }
34	34	await store.saveConversation(conversation)
35	35	await store.saveConversation({ ...conversation, sessionId: 's2' })
36	36	expect(await store.conversation('g')).toEqual({ ...conversation, sessionId: 's2' })