feat(session): make generated titles optional (#39747)

packages/core/src/database/migration.gen.ts

@@ -58,5 +58,6 @@ export const migrations = (
     import("./migration/20260722011141_delete_tool_progress_events"),
     import("./migration/20260722170000_canonical_tool_results"),
     import("./migration/20260729022634_session_fork_boundary"),
+    import("./migration/20260730195856_optional_session_title"),
   ])
 ).map((module) => module.default) satisfies DatabaseMigration.Migration[]

packages/core/src/database/migration/20260730195856_optional_session_title.ts

@@ -0,0 +1,14 @@
+import { Effect } from "effect"
+import type { DatabaseMigration } from "../migration"
+
+export default {
+  id: "20260730195856_optional_session_title",
+  up(tx) {
+    return Effect.gen(function* () {
+      yield* tx.run(`ALTER TABLE \`session\` RENAME COLUMN \`title\` TO \`title_old\``)
+      yield* tx.run(`ALTER TABLE \`session\` ADD COLUMN \`title\` text`)
+      yield* tx.run(`UPDATE \`session\` SET \`title\` = \`title_old\``)
+      yield* tx.run(`ALTER TABLE \`session\` DROP COLUMN \`title_old\``)
+    })
+  },
+} satisfies DatabaseMigration.Migration

packages/core/src/database/schema.gen.ts

@@ -217,7 +217,7 @@ export default {
           \`slug\` text NOT NULL,
           \`directory\` text NOT NULL,
           \`path\` text,
-          \`title\` text NOT NULL,
+          \`title\` text,
           \`version\` text NOT NULL,
           \`share_url\` text,
           \`summary_additions\` integer,

packages/core/src/session.ts

@@ -374,7 +374,7 @@ const layer = Layer.effect(
           directory: location.directory,
           path: path.relative(project.directory, location.directory).replaceAll("\\", "/"),
           workspaceID: location.workspaceID ? Workspace.ID.make(location.workspaceID) : undefined,
-          title: input.title ?? `New session - ${new Date(now).toISOString()}`,
+          title: input.title,
           agent: input.agent,
           model: input.model
             ? {

packages/core/src/session/info.ts

@@ -17,7 +17,7 @@ export function fromRow(row: typeof SessionTable.$inferSelect): SessionSchema.In
   return SessionSchema.Info.make({
     id: SessionSchema.ID.make(row.id),
     projectID: Project.ID.make(row.project_id),
-    title: row.title,
+    title: row.title ?? undefined,
     parentID: row.parent_id ? SessionSchema.ID.make(row.parent_id) : undefined,
     fork:
       row.fork_session_id && row.fork_boundary

packages/core/src/session/projector.ts

@@ -43,7 +43,8 @@ type Usage = {
 
 const ForkBatchSize = 500
 
-const forkTitle = (value: string) => {
+const forkTitle = (value?: string) => {
+  if (value === undefined) return
   const match = value.match(/^(.+) \(fork #(\d+)\)$/)
   if (match) return `${match[1]} (fork #${Number.parseInt(match[2], 10) + 1})`
   return `${value} (fork #1)`
@@ -216,7 +217,7 @@ const projectFork = Effect.fn("SessionProjector.projectFork")(function* (
       slug: Slug.create(),
       directory: parent.directory,
       path: parent.path,
-      title: forkTitle(parent.title),
+      title: forkTitle(parent.title ?? undefined),
       agent: parent.agent,
       model: parent.model,
       version: parent.version,

packages/core/src/session/sql.ts

@@ -36,7 +36,7 @@ export const SessionTable = sqliteTable(
     slug: text().notNull(),
     directory: directoryColumn().notNull(),
     path: pathColumn(),
-    title: text().notNull(),
+    title: text(),
     version: text().notNull(),
     share_url: text(),
     summary_additions: integer(),