feat: unwrap usession namespace to flat exports + barrel (#22713)

3 files changed, 818 insertions, 819 deletions

diff --git a/packages/opencode/src/session/index.ts b/packages/opencode/src/session/index.ts
index 585b9a135..1b79fd01a 100644
--- a/packages/opencode/src/session/index.ts
+++ b/packages/opencode/src/session/index.ts
@@ -1,818 +1 @@
-import { Slug } from "@opencode-ai/shared/util/slug"
-import path from "path"
-import { BusEvent } from "@/bus/bus-event"
-import { Bus } from "@/bus"
-import { Decimal } from "decimal.js"
-import z from "zod"
-import { type ProviderMetadata, type LanguageModelUsage } from "ai"
-import { Flag } from "../flag/flag"
-import { Installation } from "../installation"
-
-import { Database, NotFoundError, eq, and, gte, isNull, desc, like, inArray, lt } from "../storage/db"
-import { SyncEvent } from "../sync"
-import type { SQL } from "../storage/db"
-import { PartTable, SessionTable } from "./session.sql"
-import { ProjectTable } from "../project/project.sql"
-import { Storage } from "@/storage/storage"
-import { Log } from "../util/log"
-import { updateSchema } from "../util/update-schema"
-import { MessageV2 } from "./message-v2"
-import { Instance } from "../project/instance"
-import { InstanceState } from "@/effect/instance-state"
-import { Snapshot } from "@/snapshot"
-import { ProjectID } from "../project/schema"
-import { WorkspaceID } from "../control-plane/schema"
-import { SessionID, MessageID, PartID } from "./schema"
-
-import type { Provider } from "@/provider"
-import { Permission } from "@/permission"
-import { Global } from "@/global"
-import { Effect, Layer, Option, Context } from "effect"
-
-export namespace Session {
-  const log = Log.create({ service: "session" })
-
-  const parentTitlePrefix = "New session - "
-  const childTitlePrefix = "Child session - "
-
-  function createDefaultTitle(isChild = false) {
-    return (isChild ? childTitlePrefix : parentTitlePrefix) + new Date().toISOString()
-  }
-
-  export function isDefaultTitle(title: string) {
-    return new RegExp(
-      `^(${parentTitlePrefix}|${childTitlePrefix})\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z$`,
-    ).test(title)
-  }
-
-  type SessionRow = typeof SessionTable.$inferSelect
-
-  export function fromRow(row: SessionRow): Info {
-    const summary =
-      row.summary_additions !== null || row.summary_deletions !== null || row.summary_files !== null
-        ? {
-            additions: row.summary_additions ?? 0,
-            deletions: row.summary_deletions ?? 0,
-            files: row.summary_files ?? 0,
-            diffs: row.summary_diffs ?? undefined,
-          }
-        : undefined
-    const share = row.share_url ? { url: row.share_url } : undefined
-    const revert = row.revert ?? undefined
-    return {
-      id: row.id,
-      slug: row.slug,
-      projectID: row.project_id,
-      workspaceID: row.workspace_id ?? undefined,
-      directory: row.directory,
-      parentID: row.parent_id ?? undefined,
-      title: row.title,
-      version: row.version,
-      summary,
-      share,
-      revert,
-      permission: row.permission ?? undefined,
-      time: {
-        created: row.time_created,
-        updated: row.time_updated,
-        compacting: row.time_compacting ?? undefined,
-        archived: row.time_archived ?? undefined,
-      },
-    }
-  }
-
-  export function toRow(info: Info) {
-    return {
-      id: info.id,
-      project_id: info.projectID,
-      workspace_id: info.workspaceID,
-      parent_id: info.parentID,
-      slug: info.slug,
-      directory: info.directory,
-      title: info.title,
-      version: info.version,
-      share_url: info.share?.url,
-      summary_additions: info.summary?.additions,
-      summary_deletions: info.summary?.deletions,
-      summary_files: info.summary?.files,
-      summary_diffs: info.summary?.diffs,
-      revert: info.revert ?? null,
-      permission: info.permission,
-      time_created: info.time.created,
-      time_updated: info.time.updated,
-      time_compacting: info.time.compacting,
-      time_archived: info.time.archived,
-    }
-  }
-
-  function getForkedTitle(title: string): string {
-    const match = title.match(/^(.+) \(fork #(\d+)\)$/)
-    if (match) {
-      const base = match[1]
-      const num = parseInt(match[2], 10)
-      return `${base} (fork #${num + 1})`
-    }
-    return `${title} (fork #1)`
-  }
-
-  export const Info = z
-    .object({
-      id: SessionID.zod,
-      slug: z.string(),
-      projectID: ProjectID.zod,
-      workspaceID: WorkspaceID.zod.optional(),
-      directory: z.string(),
-      parentID: SessionID.zod.optional(),
-      summary: z
-        .object({
-          additions: z.number(),
-          deletions: z.number(),
-          files: z.number(),
-          diffs: Snapshot.FileDiff.array().optional(),
-        })
-        .optional(),
-      share: z
-        .object({
-          url: z.string(),
-        })
-        .optional(),
-      title: z.string(),
-      version: z.string(),
-      time: z.object({
-        created: z.number(),
-        updated: z.number(),
-        compacting: z.number().optional(),
-        archived: z.number().optional(),
-      }),
-      permission: Permission.Ruleset.zod.optional(),
-      revert: z
-        .object({
-          messageID: MessageID.zod,
-          partID: PartID.zod.optional(),
-          snapshot: z.string().optional(),
-          diff: z.string().optional(),
-        })
-        .optional(),
-    })
-    .meta({
-      ref: "Session",
-    })
-  export type Info = z.output<typeof Info>
-
-  export const ProjectInfo = z
-    .object({
-      id: ProjectID.zod,
-      name: z.string().optional(),
-      worktree: z.string(),
-    })
-    .meta({
-      ref: "ProjectSummary",
-    })
-  export type ProjectInfo = z.output<typeof ProjectInfo>
-
-  export const GlobalInfo = Info.extend({
-    project: ProjectInfo.nullable(),
-  }).meta({
-    ref: "GlobalSession",
-  })
-  export type GlobalInfo = z.output<typeof GlobalInfo>
-
-  export const CreateInput = z
-    .object({
-      parentID: SessionID.zod.optional(),
-      title: z.string().optional(),
-      permission: Info.shape.permission,
-      workspaceID: WorkspaceID.zod.optional(),
-    })
-    .optional()
-  export type CreateInput = z.output<typeof CreateInput>
-
-  export const ForkInput = z.object({ sessionID: SessionID.zod, messageID: MessageID.zod.optional() })
-  export const GetInput = SessionID.zod
-  export const ChildrenInput = SessionID.zod
-  export const RemoveInput = SessionID.zod
-  export const SetTitleInput = z.object({ sessionID: SessionID.zod, title: z.string() })
-  export const SetArchivedInput = z.object({ sessionID: SessionID.zod, time: z.number().optional() })
-  export const SetPermissionInput = z.object({ sessionID: SessionID.zod, permission: Permission.Ruleset.zod })
-  export const SetRevertInput = z.object({
-    sessionID: SessionID.zod,
-    revert: Info.shape.revert,
-    summary: Info.shape.summary,
-  })
-  export const MessagesInput = z.object({ sessionID: SessionID.zod, limit: z.number().optional() })
-
-  export const Event = {
-    Created: SyncEvent.define({
-      type: "session.created",
-      version: 1,
-      aggregate: "sessionID",
-      schema: z.object({
-        sessionID: SessionID.zod,
-        info: Info,
-      }),
-    }),
-    Updated: SyncEvent.define({
-      type: "session.updated",
-      version: 1,
-      aggregate: "sessionID",
-      schema: z.object({
-        sessionID: SessionID.zod,
-        info: updateSchema(Info).extend({
-          share: updateSchema(Info.shape.share.unwrap()).optional(),
-          time: updateSchema(Info.shape.time).optional(),
-        }),
-      }),
-      busSchema: z.object({
-        sessionID: SessionID.zod,
-        info: Info,
-      }),
-    }),
-    Deleted: SyncEvent.define({
-      type: "session.deleted",
-      version: 1,
-      aggregate: "sessionID",
-      schema: z.object({
-        sessionID: SessionID.zod,
-        info: Info,
-      }),
-    }),
-    Diff: BusEvent.define(
-      "session.diff",
-      z.object({
-        sessionID: SessionID.zod,
-        diff: Snapshot.FileDiff.array(),
-      }),
-    ),
-    Error: BusEvent.define(
-      "session.error",
-      z.object({
-        sessionID: SessionID.zod.optional(),
-        error: MessageV2.Assistant.shape.error,
-      }),
-    ),
-  }
-
-  export function plan(input: { slug: string; time: { created: number } }) {
-    const base = Instance.project.vcs
-      ? path.join(Instance.worktree, ".opencode", "plans")
-      : path.join(Global.Path.data, "plans")
-    return path.join(base, [input.time.created, input.slug].join("-") + ".md")
-  }
-
-  export const getUsage = (input: {
-    model: Provider.Model
-    usage: LanguageModelUsage
-    metadata?: ProviderMetadata
-  }) => {
-    const safe = (value: number) => {
-      if (!Number.isFinite(value)) return 0
-      return value
-    }
-    const inputTokens = safe(input.usage.inputTokens ?? 0)
-    const outputTokens = safe(input.usage.outputTokens ?? 0)
-    const reasoningTokens = safe(input.usage.outputTokenDetails?.reasoningTokens ?? input.usage.reasoningTokens ?? 0)
-
-    const cacheReadInputTokens = safe(
-      input.usage.inputTokenDetails?.cacheReadTokens ?? input.usage.cachedInputTokens ?? 0,
-    )
-    const cacheWriteInputTokens = safe(
-      (input.usage.inputTokenDetails?.cacheWriteTokens ??
-        input.metadata?.["anthropic"]?.["cacheCreationInputTokens"] ??
-        // google-vertex-anthropic returns metadata under "vertex" key
-        // (AnthropicMessagesLanguageModel custom provider key from 'vertex.anthropic.messages')
-        input.metadata?.["vertex"]?.["cacheCreationInputTokens"] ??
-        // @ts-expect-error
-        input.metadata?.["bedrock"]?.["usage"]?.["cacheWriteInputTokens"] ??
-        // @ts-expect-error
-        input.metadata?.["venice"]?.["usage"]?.["cacheCreationInputTokens"] ??
-        0) as number,
-    )
-
-    // AI SDK v6 normalized inputTokens to include cached tokens across all providers
-    // (including Anthropic/Bedrock which previously excluded them). Always subtract cache
-    // tokens to get the non-cached input count for separate cost calculation.
-    const adjustedInputTokens = safe(inputTokens - cacheReadInputTokens - cacheWriteInputTokens)
-
-    const total = input.usage.totalTokens
-
-    const tokens = {
-      total,
-      input: adjustedInputTokens,
-      output: safe(outputTokens - reasoningTokens),
-      reasoning: reasoningTokens,
-      cache: {
-        write: cacheWriteInputTokens,
-        read: cacheReadInputTokens,
-      },
-    }
-
-    const costInfo =
-      input.model.cost?.experimentalOver200K && tokens.input + tokens.cache.read > 200_000
-        ? input.model.cost.experimentalOver200K
-        : input.model.cost
-    return {
-      cost: safe(
-        new Decimal(0)
-          .add(new Decimal(tokens.input).mul(costInfo?.input ?? 0).div(1_000_000))
-          .add(new Decimal(tokens.output).mul(costInfo?.output ?? 0).div(1_000_000))
-          .add(new Decimal(tokens.cache.read).mul(costInfo?.cache?.read ?? 0).div(1_000_000))
-          .add(new Decimal(tokens.cache.write).mul(costInfo?.cache?.write ?? 0).div(1_000_000))
-          // TODO: update models.dev to have better pricing model, for now:
-          // charge reasoning tokens at the same rate as output tokens
-          .add(new Decimal(tokens.reasoning).mul(costInfo?.output ?? 0).div(1_000_000))
-          .toNumber(),
-      ),
-      tokens,
-    }
-  }
-
-  export class BusyError extends Error {
-    constructor(public readonly sessionID: string) {
-      super(`Session ${sessionID} is busy`)
-    }
-  }
-
-  export interface Interface {
-    readonly create: (input?: {
-      parentID?: SessionID
-      title?: string
-      permission?: Permission.Ruleset
-      workspaceID?: WorkspaceID
-    }) => Effect.Effect<Info>
-    readonly fork: (input: { sessionID: SessionID; messageID?: MessageID }) => Effect.Effect<Info>
-    readonly touch: (sessionID: SessionID) => Effect.Effect<void>
-    readonly get: (id: SessionID) => Effect.Effect<Info>
-    readonly setTitle: (input: { sessionID: SessionID; title: string }) => Effect.Effect<void>
-    readonly setArchived: (input: { sessionID: SessionID; time?: number }) => Effect.Effect<void>
-    readonly setPermission: (input: { sessionID: SessionID; permission: Permission.Ruleset }) => Effect.Effect<void>
-    readonly setRevert: (input: {
-      sessionID: SessionID
-      revert: Info["revert"]
-      summary: Info["summary"]
-    }) => Effect.Effect<void>
-    readonly clearRevert: (sessionID: SessionID) => Effect.Effect<void>
-    readonly setSummary: (input: { sessionID: SessionID; summary: Info["summary"] }) => Effect.Effect<void>
-    readonly diff: (sessionID: SessionID) => Effect.Effect<Snapshot.FileDiff[]>
-    readonly messages: (input: { sessionID: SessionID; limit?: number }) => Effect.Effect<MessageV2.WithParts[]>
-    readonly children: (parentID: SessionID) => Effect.Effect<Info[]>
-    readonly remove: (sessionID: SessionID) => Effect.Effect<void>
-    readonly updateMessage: <T extends MessageV2.Info>(msg: T) => Effect.Effect<T>
-    readonly removeMessage: (input: { sessionID: SessionID; messageID: MessageID }) => Effect.Effect<MessageID>
-    readonly removePart: (input: {
-      sessionID: SessionID
-      messageID: MessageID
-      partID: PartID
-    }) => Effect.Effect<PartID>
-    readonly getPart: (input: {
-      sessionID: SessionID
-      messageID: MessageID
-      partID: PartID
-    }) => Effect.Effect<MessageV2.Part | undefined>
-    readonly updatePart: <T extends MessageV2.Part>(part: T) => Effect.Effect<T>
-    readonly updatePartDelta: (input: {
-      sessionID: SessionID
-      messageID: MessageID
-      partID: PartID
-      field: string
-      delta: string
-    }) => Effect.Effect<void>
-    /** Finds the first message matching the predicate, searching newest-first. */
-    readonly findMessage: (
-      sessionID: SessionID,
-      predicate: (msg: MessageV2.WithParts) => boolean,
-    ) => Effect.Effect<Option.Option<MessageV2.WithParts>>
-  }
-
-  export class Service extends Context.Service<Service, Interface>()("@opencode/Session") {}
-
-  type Patch = z.infer<typeof Event.Updated.schema>["info"]
-
-  const db = <T>(fn: (d: Parameters<typeof Database.use>[0] extends (trx: infer D) => any ? D : never) => T) =>
-    Effect.sync(() => Database.use(fn))
-
-  export const layer: Layer.Layer<Service, never, Bus.Service | Storage.Service> = Layer.effect(
-    Service,
-    Effect.gen(function* () {
-      const bus = yield* Bus.Service
-      const storage = yield* Storage.Service
-
-      const createNext = Effect.fn("Session.createNext")(function* (input: {
-        id?: SessionID
-        title?: string
-        parentID?: SessionID
-        workspaceID?: WorkspaceID
-        directory: string
-        permission?: Permission.Ruleset
-      }) {
-        const ctx = yield* InstanceState.context
-        const result: Info = {
-          id: SessionID.descending(input.id),
-          slug: Slug.create(),
-          version: Installation.VERSION,
-          projectID: ctx.project.id,
-          directory: input.directory,
-          workspaceID: input.workspaceID,
-          parentID: input.parentID,
-          title: input.title ?? createDefaultTitle(!!input.parentID),
-          permission: input.permission,
-          time: {
-            created: Date.now(),
-            updated: Date.now(),
-          },
-        }
-        log.info("created", result)
-
-        yield* Effect.sync(() => SyncEvent.run(Event.Created, { sessionID: result.id, info: result }))
-
-        if (!Flag.OPENCODE_EXPERIMENTAL_WORKSPACES) {
-          // This only exist for backwards compatibility. We should not be
-          // manually publishing this event; it is a sync event now
-          yield* bus.publish(Event.Updated, {
-            sessionID: result.id,
-            info: result,
-          })
-        }
-
-        return result
-      })
-
-      const get = Effect.fn("Session.get")(function* (id: SessionID) {
-        const row = yield* db((d) => d.select().from(SessionTable).where(eq(SessionTable.id, id)).get())
-        if (!row) throw new NotFoundError({ message: `Session not found: ${id}` })
-        return fromRow(row)
-      })
-
-      const children = Effect.fn("Session.children")(function* (parentID: SessionID) {
-        const rows = yield* db((d) =>
-          d
-            .select()
-            .from(SessionTable)
-            .where(and(eq(SessionTable.parent_id, parentID)))
-            .all(),
-        )
-        return rows.map(fromRow)
-      })
-
-      const remove: Interface["remove"] = Effect.fnUntraced(function* (sessionID: SessionID) {
-        try {
-          const session = yield* get(sessionID)
-          const kids = yield* children(sessionID)
-          for (const child of kids) {
-            yield* remove(child.id)
-          }
-
-          // `remove` needs to work in all cases, such as a broken
-          // sessions that run cleanup. In certain cases these will
-          // run without any instance state, so we need to turn off
-          // publishing of events in that case
-          const hasInstance = yield* InstanceState.directory.pipe(
-            Effect.as(true),
-            Effect.catchCause(() => Effect.succeed(false)),
-          )
-
-          yield* Effect.sync(() => {
-            SyncEvent.run(Event.Deleted, { sessionID, info: session }, { publish: hasInstance })
-            SyncEvent.remove(sessionID)
-          })
-        } catch (e) {
-          log.error(e)
-        }
-      })
-
-      const updateMessage = <T extends MessageV2.Info>(msg: T): Effect.Effect<T> =>
-        Effect.gen(function* () {
-          yield* Effect.sync(() => SyncEvent.run(MessageV2.Event.Updated, { sessionID: msg.sessionID, info: msg }))
-          return msg
-        }).pipe(Effect.withSpan("Session.updateMessage"))
-
-      const updatePart = <T extends MessageV2.Part>(part: T): Effect.Effect<T> =>
-        Effect.gen(function* () {
-          yield* Effect.sync(() =>
-            SyncEvent.run(MessageV2.Event.PartUpdated, {
-              sessionID: part.sessionID,
-              part: structuredClone(part),
-              time: Date.now(),
-            }),
-          )
-          return part
-        }).pipe(Effect.withSpan("Session.updatePart"))
-
-      const getPart: Interface["getPart"] = Effect.fn("Session.getPart")(function* (input) {
-        const row = Database.use((db) =>
-          db
-            .select()
-            .from(PartTable)
-            .where(
-              and(
-                eq(PartTable.session_id, input.sessionID),
-                eq(PartTable.message_id, input.messageID),
-                eq(PartTable.id, input.partID),
-              ),
-            )
-            .get(),
-        )
-        if (!row) return
-        return {
-          ...row.data,
-          id: row.id,
-          sessionID: row.session_id,
-          messageID: row.message_id,
-        } as MessageV2.Part
-      })
-
-      const create = Effect.fn("Session.create")(function* (input?: {
-        parentID?: SessionID
-        title?: string
-        permission?: Permission.Ruleset
-        workspaceID?: WorkspaceID
-      }) {
-        const directory = yield* InstanceState.directory
-        return yield* createNext({
-          parentID: input?.parentID,
-          directory,
-          title: input?.title,
-          permission: input?.permission,
-          workspaceID: input?.workspaceID,
-        })
-      })
-
-      const fork = Effect.fn("Session.fork")(function* (input: { sessionID: SessionID; messageID?: MessageID }) {
-        const directory = yield* InstanceState.directory
-        const original = yield* get(input.sessionID)
-        const title = getForkedTitle(original.title)
-        const session = yield* createNext({
-          directory,
-          workspaceID: original.workspaceID,
-          title,
-        })
-        const msgs = yield* messages({ sessionID: input.sessionID })
-        const idMap = new Map<string, MessageID>()
-
-        for (const msg of msgs) {
-          if (input.messageID && msg.info.id >= input.messageID) break
-          const newID = MessageID.ascending()
-          idMap.set(msg.info.id, newID)
-
-          const parentID = msg.info.role === "assistant" && msg.info.parentID ? idMap.get(msg.info.parentID) : undefined
-          const cloned = yield* updateMessage({
-            ...msg.info,
-            sessionID: session.id,
-            id: newID,
-            ...(parentID && { parentID }),
-          })
-
-          for (const part of msg.parts) {
-            yield* updatePart({
-              ...part,
-              id: PartID.ascending(),
-              messageID: cloned.id,
-              sessionID: session.id,
-            })
-          }
-        }
-        return session
-      })
-
-      const patch = (sessionID: SessionID, info: Patch) =>
-        Effect.sync(() => SyncEvent.run(Event.Updated, { sessionID, info }))
-
-      const touch = Effect.fn("Session.touch")(function* (sessionID: SessionID) {
-        yield* patch(sessionID, { time: { updated: Date.now() } })
-      })
-
-      const setTitle = Effect.fn("Session.setTitle")(function* (input: { sessionID: SessionID; title: string }) {
-        yield* patch(input.sessionID, { title: input.title })
-      })
-
-      const setArchived = Effect.fn("Session.setArchived")(function* (input: { sessionID: SessionID; time?: number }) {
-        yield* patch(input.sessionID, { time: { archived: input.time } })
-      })
-
-      const setPermission = Effect.fn("Session.setPermission")(function* (input: {
-        sessionID: SessionID
-        permission: Permission.Ruleset
-      }) {
-        yield* patch(input.sessionID, { permission: input.permission, time: { updated: Date.now() } })
-      })
-
-      const setRevert = Effect.fn("Session.setRevert")(function* (input: {
-        sessionID: SessionID
-        revert: Info["revert"]
-        summary: Info["summary"]
-      }) {
-        yield* patch(input.sessionID, { summary: input.summary, time: { updated: Date.now() }, revert: input.revert })
-      })
-
-      const clearRevert = Effect.fn("Session.clearRevert")(function* (sessionID: SessionID) {
-        yield* patch(sessionID, { time: { updated: Date.now() }, revert: null })
-      })
-
-      const setSummary = Effect.fn("Session.setSummary")(function* (input: {
-        sessionID: SessionID
-        summary: Info["summary"]
-      }) {
-        yield* patch(input.sessionID, { time: { updated: Date.now() }, summary: input.summary })
-      })
-
-      const diff = Effect.fn("Session.diff")(function* (sessionID: SessionID) {
-        return yield* storage
-          .read<Snapshot.FileDiff[]>(["session_diff", sessionID])
-          .pipe(Effect.orElseSucceed((): Snapshot.FileDiff[] => []))
-      })
-
-      const messages = Effect.fn("Session.messages")(function* (input: { sessionID: SessionID; limit?: number }) {
-        if (input.limit) {
-          return MessageV2.page({ sessionID: input.sessionID, limit: input.limit }).items
-        }
-        return Array.from(MessageV2.stream(input.sessionID)).reverse()
-      })
-
-      const removeMessage = Effect.fn("Session.removeMessage")(function* (input: {
-        sessionID: SessionID
-        messageID: MessageID
-      }) {
-        yield* Effect.sync(() =>
-          SyncEvent.run(MessageV2.Event.Removed, {
-            sessionID: input.sessionID,
-            messageID: input.messageID,
-          }),
-        )
-        return input.messageID
-      })
-
-      const removePart = Effect.fn("Session.removePart")(function* (input: {
-        sessionID: SessionID
-        messageID: MessageID
-        partID: PartID
-      }) {
-        yield* Effect.sync(() =>
-          SyncEvent.run(MessageV2.Event.PartRemoved, {
-            sessionID: input.sessionID,
-            messageID: input.messageID,
-            partID: input.partID,
-          }),
-        )
-        return input.partID
-      })
-
-      const updatePartDelta = Effect.fn("Session.updatePartDelta")(function* (input: {
-        sessionID: SessionID
-        messageID: MessageID
-        partID: PartID
-        field: string
-        delta: string
-      }) {
-        yield* bus.publish(MessageV2.Event.PartDelta, input)
-      })
-
-      /** Finds the first message matching the predicate, searching newest-first. */
-      const findMessage = Effect.fn("Session.findMessage")(function* (
-        sessionID: SessionID,
-        predicate: (msg: MessageV2.WithParts) => boolean,
-      ) {
-        for (const item of MessageV2.stream(sessionID)) {
-          if (predicate(item)) return Option.some(item)
-        }
-        return Option.none<MessageV2.WithParts>()
-      })
-
-      return Service.of({
-        create,
-        fork,
-        touch,
-        get,
-        setTitle,
-        setArchived,
-        setPermission,
-        setRevert,
-        clearRevert,
-        setSummary,
-        diff,
-        messages,
-        children,
-        remove,
-        updateMessage,
-        removeMessage,
-        removePart,
-        updatePart,
-        getPart,
-        updatePartDelta,
-        findMessage,
-      })
-    }),
-  )
-
-  export const defaultLayer = layer.pipe(Layer.provide(Bus.layer), Layer.provide(Storage.defaultLayer))
-
-  export function* list(input?: {
-    directory?: string
-    workspaceID?: WorkspaceID
-    roots?: boolean
-    start?: number
-    search?: string
-    limit?: number
-  }) {
-    const project = Instance.project
-    const conditions = [eq(SessionTable.project_id, project.id)]
-
-    if (input?.workspaceID) {
-      conditions.push(eq(SessionTable.workspace_id, input.workspaceID))
-    }
-    if (input?.directory) {
-      conditions.push(eq(SessionTable.directory, input.directory))
-    }
-    if (input?.roots) {
-      conditions.push(isNull(SessionTable.parent_id))
-    }
-    if (input?.start) {
-      conditions.push(gte(SessionTable.time_updated, input.start))
-    }
-    if (input?.search) {
-      conditions.push(like(SessionTable.title, `%${input.search}%`))
-    }
-
-    const limit = input?.limit ?? 100
-
-    const rows = Database.use((db) =>
-      db
-        .select()
-        .from(SessionTable)
-        .where(and(...conditions))
-        .orderBy(desc(SessionTable.time_updated))
-        .limit(limit)
-        .all(),
-    )
-    for (const row of rows) {
-      yield fromRow(row)
-    }
-  }
-
-  export function* listGlobal(input?: {
-    directory?: string
-    roots?: boolean
-    start?: number
-    cursor?: number
-    search?: string
-    limit?: number
-    archived?: boolean
-  }) {
-    const conditions: SQL[] = []
-
-    if (input?.directory) {
-      conditions.push(eq(SessionTable.directory, input.directory))
-    }
-    if (input?.roots) {
-      conditions.push(isNull(SessionTable.parent_id))
-    }
-    if (input?.start) {
-      conditions.push(gte(SessionTable.time_updated, input.start))
-    }
-    if (input?.cursor) {
-      conditions.push(lt(SessionTable.time_updated, input.cursor))
-    }
-    if (input?.search) {
-      conditions.push(like(SessionTable.title, `%${input.search}%`))
-    }
-    if (!input?.archived) {
-      conditions.push(isNull(SessionTable.time_archived))
-    }
-
-    const limit = input?.limit ?? 100
-
-    const rows = Database.use((db) => {
-      const query =
-        conditions.length > 0
-          ? db
-              .select()
-              .from(SessionTable)
-              .where(and(...conditions))
-          : db.select().from(SessionTable)
-      return query.orderBy(desc(SessionTable.time_updated), desc(SessionTable.id)).limit(limit).all()
-    })
-
-    const ids = [...new Set(rows.map((row) => row.project_id))]
-    const projects = new Map<string, ProjectInfo>()
-
-    if (ids.length > 0) {
-      const items = Database.use((db) =>
-        db
-          .select({ id: ProjectTable.id, name: ProjectTable.name, worktree: ProjectTable.worktree })
-          .from(ProjectTable)
-          .where(inArray(ProjectTable.id, ids))
-          .all(),
-      )
-      for (const item of items) {
-        projects.set(item.id, {
-          id: item.id,
-          name: item.name ?? undefined,
-          worktree: item.worktree,
-        })
-      }
-    }
-
-    for (const row of rows) {
-      const project = projects.get(row.project_id) ?? null
-      yield { ...fromRow(row), project }
-    }
-  }
-}
+export * as Session from "./session"
diff --git a/packages/opencode/src/session/projectors.ts b/packages/opencode/src/session/projectors.ts
index a1b2e401d..bc083105c 100644
--- a/packages/opencode/src/session/projectors.ts
+++ b/packages/opencode/src/session/projectors.ts
@@ -1,6 +1,6 @@
 import { NotFoundError, eq, and } from "../storage/db"
 import { SyncEvent } from "@/sync"
-import { Session } from "./index"
+import { Session } from "."
 import { MessageV2 } from "./message-v2"
 import { SessionTable, MessageTable, PartTable } from "./session.sql"
 import { Log } from "../util/log"
diff --git a/packages/opencode/src/session/session.ts b/packages/opencode/src/session/session.ts
new file mode 100644
index 000000000..369a2085f
--- /dev/null
+++ b/packages/opencode/src/session/session.ts
@@ -0,0 +1,816 @@
+import { Slug } from "@opencode-ai/shared/util/slug"
+import path from "path"
+import { BusEvent } from "@/bus/bus-event"
+import { Bus } from "@/bus"
+import { Decimal } from "decimal.js"
+import z from "zod"
+import { type ProviderMetadata, type LanguageModelUsage } from "ai"
+import { Flag } from "../flag/flag"
+import { Installation } from "../installation"
+
+import { Database, NotFoundError, eq, and, gte, isNull, desc, like, inArray, lt } from "../storage/db"
+import { SyncEvent } from "../sync"
+import type { SQL } from "../storage/db"
+import { PartTable, SessionTable } from "./session.sql"
+import { ProjectTable } from "../project/project.sql"
+import { Storage } from "@/storage/storage"
+import { Log } from "../util/log"
+import { updateSchema } from "../util/update-schema"
+import { MessageV2 } from "./message-v2"
+import { Instance } from "../project/instance"
+import { InstanceState } from "@/effect/instance-state"
+import { Snapshot } from "@/snapshot"
+import { ProjectID } from "../project/schema"
+import { WorkspaceID } from "../control-plane/schema"
+import { SessionID, MessageID, PartID } from "./schema"
+
+import type { Provider } from "@/provider"
+import { Permission } from "@/permission"
+import { Global } from "@/global"
+import { Effect, Layer, Option, Context } from "effect"
+
+const log = Log.create({ service: "session" })
+
+const parentTitlePrefix = "New session - "
+const childTitlePrefix = "Child session - "
+
+function createDefaultTitle(isChild = false) {
+  return (isChild ? childTitlePrefix : parentTitlePrefix) + new Date().toISOString()
+}
+
+export function isDefaultTitle(title: string) {
+  return new RegExp(
+    `^(${parentTitlePrefix}|${childTitlePrefix})\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z$`,
+  ).test(title)
+}
+
+type SessionRow = typeof SessionTable.$inferSelect
+
+export function fromRow(row: SessionRow): Info {
+  const summary =
+    row.summary_additions !== null || row.summary_deletions !== null || row.summary_files !== null
+      ? {
+          additions: row.summary_additions ?? 0,
+          deletions: row.summary_deletions ?? 0,
+          files: row.summary_files ?? 0,
+          diffs: row.summary_diffs ?? undefined,
+        }
+      : undefined
+  const share = row.share_url ? { url: row.share_url } : undefined
+  const revert = row.revert ?? undefined
+  return {
+    id: row.id,
+    slug: row.slug,
+    projectID: row.project_id,
+    workspaceID: row.workspace_id ?? undefined,
+    directory: row.directory,
+    parentID: row.parent_id ?? undefined,
+    title: row.title,
+    version: row.version,
+    summary,
+    share,
+    revert,
+    permission: row.permission ?? undefined,
+    time: {
+      created: row.time_created,
+      updated: row.time_updated,
+      compacting: row.time_compacting ?? undefined,
+      archived: row.time_archived ?? undefined,
+    },
+  }
+}
+
+export function toRow(info: Info) {
+  return {
+    id: info.id,
+    project_id: info.projectID,
+    workspace_id: info.workspaceID,
+    parent_id: info.parentID,
+    slug: info.slug,
+    directory: info.directory,
+    title: info.title,
+    version: info.version,
+    share_url: info.share?.url,
+    summary_additions: info.summary?.additions,
+    summary_deletions: info.summary?.deletions,
+    summary_files: info.summary?.files,
+    summary_diffs: info.summary?.diffs,
+    revert: info.revert ?? null,
+    permission: info.permission,
+    time_created: info.time.created,
+    time_updated: info.time.updated,
+    time_compacting: info.time.compacting,
+    time_archived: info.time.archived,
+  }
+}
+
+function getForkedTitle(title: string): string {
+  const match = title.match(/^(.+) \(fork #(\d+)\)$/)
+  if (match) {
+    const base = match[1]
+    const num = parseInt(match[2], 10)
+    return `${base} (fork #${num + 1})`
+  }
+  return `${title} (fork #1)`
+}
+
+export const Info = z
+  .object({
+    id: SessionID.zod,
+    slug: z.string(),
+    projectID: ProjectID.zod,
+    workspaceID: WorkspaceID.zod.optional(),
+    directory: z.string(),
+    parentID: SessionID.zod.optional(),
+    summary: z
+      .object({
+        additions: z.number(),
+        deletions: z.number(),
+        files: z.number(),
+        diffs: Snapshot.FileDiff.array().optional(),
+      })
+      .optional(),
+    share: z
+      .object({
+        url: z.string(),
+      })
+      .optional(),
+    title: z.string(),
+    version: z.string(),
+    time: z.object({
+      created: z.number(),
+      updated: z.number(),
+      compacting: z.number().optional(),
+      archived: z.number().optional(),
+    }),
+    permission: Permission.Ruleset.zod.optional(),
+    revert: z
+      .object({
+        messageID: MessageID.zod,
+        partID: PartID.zod.optional(),
+        snapshot: z.string().optional(),
+        diff: z.string().optional(),
+      })
+      .optional(),
+  })
+  .meta({
+    ref: "Session",
+  })
+export type Info = z.output<typeof Info>
+
+export const ProjectInfo = z
+  .object({
+    id: ProjectID.zod,
+    name: z.string().optional(),
+    worktree: z.string(),
+  })
+  .meta({
+    ref: "ProjectSummary",
+  })
+export type ProjectInfo = z.output<typeof ProjectInfo>
+
+export const GlobalInfo = Info.extend({
+  project: ProjectInfo.nullable(),
+}).meta({
+  ref: "GlobalSession",
+})
+export type GlobalInfo = z.output<typeof GlobalInfo>
+
+export const CreateInput = z
+  .object({
+    parentID: SessionID.zod.optional(),
+    title: z.string().optional(),
+    permission: Info.shape.permission,
+    workspaceID: WorkspaceID.zod.optional(),
+  })
+  .optional()
+export type CreateInput = z.output<typeof CreateInput>
+
+export const ForkInput = z.object({ sessionID: SessionID.zod, messageID: MessageID.zod.optional() })
+export const GetInput = SessionID.zod
+export const ChildrenInput = SessionID.zod
+export const RemoveInput = SessionID.zod
+export const SetTitleInput = z.object({ sessionID: SessionID.zod, title: z.string() })
+export const SetArchivedInput = z.object({ sessionID: SessionID.zod, time: z.number().optional() })
+export const SetPermissionInput = z.object({ sessionID: SessionID.zod, permission: Permission.Ruleset.zod })
+export const SetRevertInput = z.object({
+  sessionID: SessionID.zod,
+  revert: Info.shape.revert,
+  summary: Info.shape.summary,
+})
+export const MessagesInput = z.object({ sessionID: SessionID.zod, limit: z.number().optional() })
+
+export const Event = {
+  Created: SyncEvent.define({
+    type: "session.created",
+    version: 1,
+    aggregate: "sessionID",
+    schema: z.object({
+      sessionID: SessionID.zod,
+      info: Info,
+    }),
+  }),
+  Updated: SyncEvent.define({
+    type: "session.updated",
+    version: 1,
+    aggregate: "sessionID",
+    schema: z.object({
+      sessionID: SessionID.zod,
+      info: updateSchema(Info).extend({
+        share: updateSchema(Info.shape.share.unwrap()).optional(),
+        time: updateSchema(Info.shape.time).optional(),
+      }),
+    }),
+    busSchema: z.object({
+      sessionID: SessionID.zod,
+      info: Info,
+    }),
+  }),
+  Deleted: SyncEvent.define({
+    type: "session.deleted",
+    version: 1,
+    aggregate: "sessionID",
+    schema: z.object({
+      sessionID: SessionID.zod,
+      info: Info,
+    }),
+  }),
+  Diff: BusEvent.define(
+    "session.diff",
+    z.object({
+      sessionID: SessionID.zod,
+      diff: Snapshot.FileDiff.array(),
+    }),
+  ),
+  Error: BusEvent.define(
+    "session.error",
+    z.object({
+      sessionID: SessionID.zod.optional(),
+      error: MessageV2.Assistant.shape.error,
+    }),
+  ),
+}
+
+export function plan(input: { slug: string; time: { created: number } }) {
+  const base = Instance.project.vcs
+    ? path.join(Instance.worktree, ".opencode", "plans")
+    : path.join(Global.Path.data, "plans")
+  return path.join(base, [input.time.created, input.slug].join("-") + ".md")
+}
+
+export const getUsage = (input: {
+  model: Provider.Model
+  usage: LanguageModelUsage
+  metadata?: ProviderMetadata
+}) => {
+  const safe = (value: number) => {
+    if (!Number.isFinite(value)) return 0
+    return value
+  }
+  const inputTokens = safe(input.usage.inputTokens ?? 0)
+  const outputTokens = safe(input.usage.outputTokens ?? 0)
+  const reasoningTokens = safe(input.usage.outputTokenDetails?.reasoningTokens ?? input.usage.reasoningTokens ?? 0)
+
+  const cacheReadInputTokens = safe(
+    input.usage.inputTokenDetails?.cacheReadTokens ?? input.usage.cachedInputTokens ?? 0,
+  )
+  const cacheWriteInputTokens = safe(
+    (input.usage.inputTokenDetails?.cacheWriteTokens ??
+      input.metadata?.["anthropic"]?.["cacheCreationInputTokens"] ??
+      // google-vertex-anthropic returns metadata under "vertex" key
+      // (AnthropicMessagesLanguageModel custom provider key from 'vertex.anthropic.messages')
+      input.metadata?.["vertex"]?.["cacheCreationInputTokens"] ??
+      // @ts-expect-error
+      input.metadata?.["bedrock"]?.["usage"]?.["cacheWriteInputTokens"] ??
+      // @ts-expect-error
+      input.metadata?.["venice"]?.["usage"]?.["cacheCreationInputTokens"] ??
+      0) as number,
+  )
+
+  // AI SDK v6 normalized inputTokens to include cached tokens across all providers
+  // (including Anthropic/Bedrock which previously excluded them). Always subtract cache
+  // tokens to get the non-cached input count for separate cost calculation.
+  const adjustedInputTokens = safe(inputTokens - cacheReadInputTokens - cacheWriteInputTokens)
+
+  const total = input.usage.totalTokens
+
+  const tokens = {
+    total,
+    input: adjustedInputTokens,
+    output: safe(outputTokens - reasoningTokens),
+    reasoning: reasoningTokens,
+    cache: {
+      write: cacheWriteInputTokens,
+      read: cacheReadInputTokens,
+    },
+  }
+
+  const costInfo =
+    input.model.cost?.experimentalOver200K && tokens.input + tokens.cache.read > 200_000
+      ? input.model.cost.experimentalOver200K
+      : input.model.cost
+  return {
+    cost: safe(
+      new Decimal(0)
+        .add(new Decimal(tokens.input).mul(costInfo?.input ?? 0).div(1_000_000))
+        .add(new Decimal(tokens.output).mul(costInfo?.output ?? 0).div(1_000_000))
+        .add(new Decimal(tokens.cache.read).mul(costInfo?.cache?.read ?? 0).div(1_000_000))
+        .add(new Decimal(tokens.cache.write).mul(costInfo?.cache?.write ?? 0).div(1_000_000))
+        // TODO: update models.dev to have better pricing model, for now:
+        // charge reasoning tokens at the same rate as output tokens
+        .add(new Decimal(tokens.reasoning).mul(costInfo?.output ?? 0).div(1_000_000))
+        .toNumber(),
+    ),
+    tokens,
+  }
+}
+
+export class BusyError extends Error {
+  constructor(public readonly sessionID: string) {
+    super(`Session ${sessionID} is busy`)
+  }
+}
+
+export interface Interface {
+  readonly create: (input?: {
+    parentID?: SessionID
+    title?: string
+    permission?: Permission.Ruleset
+    workspaceID?: WorkspaceID
+  }) => Effect.Effect<Info>
+  readonly fork: (input: { sessionID: SessionID; messageID?: MessageID }) => Effect.Effect<Info>
+  readonly touch: (sessionID: SessionID) => Effect.Effect<void>
+  readonly get: (id: SessionID) => Effect.Effect<Info>
+  readonly setTitle: (input: { sessionID: SessionID; title: string }) => Effect.Effect<void>
+  readonly setArchived: (input: { sessionID: SessionID; time?: number }) => Effect.Effect<void>
+  readonly setPermission: (input: { sessionID: SessionID; permission: Permission.Ruleset }) => Effect.Effect<void>
+  readonly setRevert: (input: {
+    sessionID: SessionID
+    revert: Info["revert"]
+    summary: Info["summary"]
+  }) => Effect.Effect<void>
+  readonly clearRevert: (sessionID: SessionID) => Effect.Effect<void>
+  readonly setSummary: (input: { sessionID: SessionID; summary: Info["summary"] }) => Effect.Effect<void>
+  readonly diff: (sessionID: SessionID) => Effect.Effect<Snapshot.FileDiff[]>
+  readonly messages: (input: { sessionID: SessionID; limit?: number }) => Effect.Effect<MessageV2.WithParts[]>
+  readonly children: (parentID: SessionID) => Effect.Effect<Info[]>
+  readonly remove: (sessionID: SessionID) => Effect.Effect<void>
+  readonly updateMessage: <T extends MessageV2.Info>(msg: T) => Effect.Effect<T>
+  readonly removeMessage: (input: { sessionID: SessionID; messageID: MessageID }) => Effect.Effect<MessageID>
+  readonly removePart: (input: {
+    sessionID: SessionID
+    messageID: MessageID
+    partID: PartID
+  }) => Effect.Effect<PartID>
+  readonly getPart: (input: {
+    sessionID: SessionID
+    messageID: MessageID
+    partID: PartID
+  }) => Effect.Effect<MessageV2.Part | undefined>
+  readonly updatePart: <T extends MessageV2.Part>(part: T) => Effect.Effect<T>
+  readonly updatePartDelta: (input: {
+    sessionID: SessionID
+    messageID: MessageID
+    partID: PartID
+    field: string
+    delta: string
+  }) => Effect.Effect<void>
+  /** Finds the first message matching the predicate, searching newest-first. */
+  readonly findMessage: (
+    sessionID: SessionID,
+    predicate: (msg: MessageV2.WithParts) => boolean,
+  ) => Effect.Effect<Option.Option<MessageV2.WithParts>>
+}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/Session") {}
+
+type Patch = z.infer<typeof Event.Updated.schema>["info"]
+
+const db = <T>(fn: (d: Parameters<typeof Database.use>[0] extends (trx: infer D) => any ? D : never) => T) =>
+  Effect.sync(() => Database.use(fn))
+
+export const layer: Layer.Layer<Service, never, Bus.Service | Storage.Service> = Layer.effect(
+  Service,
+  Effect.gen(function* () {
+    const bus = yield* Bus.Service
+    const storage = yield* Storage.Service
+
+    const createNext = Effect.fn("Session.createNext")(function* (input: {
+      id?: SessionID
+      title?: string
+      parentID?: SessionID
+      workspaceID?: WorkspaceID
+      directory: string
+      permission?: Permission.Ruleset
+    }) {
+      const ctx = yield* InstanceState.context
+      const result: Info = {
+        id: SessionID.descending(input.id),
+        slug: Slug.create(),
+        version: Installation.VERSION,
+        projectID: ctx.project.id,
+        directory: input.directory,
+        workspaceID: input.workspaceID,
+        parentID: input.parentID,
+        title: input.title ?? createDefaultTitle(!!input.parentID),
+        permission: input.permission,
+        time: {
+          created: Date.now(),
+          updated: Date.now(),
+        },
+      }
+      log.info("created", result)
+
+      yield* Effect.sync(() => SyncEvent.run(Event.Created, { sessionID: result.id, info: result }))
+
+      if (!Flag.OPENCODE_EXPERIMENTAL_WORKSPACES) {
+        // This only exist for backwards compatibility. We should not be
+        // manually publishing this event; it is a sync event now
+        yield* bus.publish(Event.Updated, {
+          sessionID: result.id,
+          info: result,
+        })
+      }
+
+      return result
+    })
+
+    const get = Effect.fn("Session.get")(function* (id: SessionID) {
+      const row = yield* db((d) => d.select().from(SessionTable).where(eq(SessionTable.id, id)).get())
+      if (!row) throw new NotFoundError({ message: `Session not found: ${id}` })
+      return fromRow(row)
+    })
+
+    const children = Effect.fn("Session.children")(function* (parentID: SessionID) {
+      const rows = yield* db((d) =>
+        d
+          .select()
+          .from(SessionTable)
+          .where(and(eq(SessionTable.parent_id, parentID)))
+          .all(),
+      )
+      return rows.map(fromRow)
+    })
+
+    const remove: Interface["remove"] = Effect.fnUntraced(function* (sessionID: SessionID) {
+      try {
+        const session = yield* get(sessionID)
+        const kids = yield* children(sessionID)
+        for (const child of kids) {
+          yield* remove(child.id)
+        }
+
+        // `remove` needs to work in all cases, such as a broken
+        // sessions that run cleanup. In certain cases these will
+        // run without any instance state, so we need to turn off
+        // publishing of events in that case
+        const hasInstance = yield* InstanceState.directory.pipe(
+          Effect.as(true),
+          Effect.catchCause(() => Effect.succeed(false)),
+        )
+
+        yield* Effect.sync(() => {
+          SyncEvent.run(Event.Deleted, { sessionID, info: session }, { publish: hasInstance })
+          SyncEvent.remove(sessionID)
+        })
+      } catch (e) {
+        log.error(e)
+      }
+    })
+
+    const updateMessage = <T extends MessageV2.Info>(msg: T): Effect.Effect<T> =>
+      Effect.gen(function* () {
+        yield* Effect.sync(() => SyncEvent.run(MessageV2.Event.Updated, { sessionID: msg.sessionID, info: msg }))
+        return msg
+      }).pipe(Effect.withSpan("Session.updateMessage"))
+
+    const updatePart = <T extends MessageV2.Part>(part: T): Effect.Effect<T> =>
+      Effect.gen(function* () {
+        yield* Effect.sync(() =>
+          SyncEvent.run(MessageV2.Event.PartUpdated, {
+            sessionID: part.sessionID,
+            part: structuredClone(part),
+            time: Date.now(),
+          }),
+        )
+        return part
+      }).pipe(Effect.withSpan("Session.updatePart"))
+
+    const getPart: Interface["getPart"] = Effect.fn("Session.getPart")(function* (input) {
+      const row = Database.use((db) =>
+        db
+          .select()
+          .from(PartTable)
+          .where(
+            and(
+              eq(PartTable.session_id, input.sessionID),
+              eq(PartTable.message_id, input.messageID),
+              eq(PartTable.id, input.partID),
+            ),
+          )
+          .get(),
+      )
+      if (!row) return
+      return {
+        ...row.data,
+        id: row.id,
+        sessionID: row.session_id,
+        messageID: row.message_id,
+      } as MessageV2.Part
+    })
+
+    const create = Effect.fn("Session.create")(function* (input?: {
+      parentID?: SessionID
+      title?: string
+      permission?: Permission.Ruleset
+      workspaceID?: WorkspaceID
+    }) {
+      const directory = yield* InstanceState.directory
+      return yield* createNext({
+        parentID: input?.parentID,
+        directory,
+        title: input?.title,
+        permission: input?.permission,
+        workspaceID: input?.workspaceID,
+      })
+    })
+
+    const fork = Effect.fn("Session.fork")(function* (input: { sessionID: SessionID; messageID?: MessageID }) {
+      const directory = yield* InstanceState.directory
+      const original = yield* get(input.sessionID)
+      const title = getForkedTitle(original.title)
+      const session = yield* createNext({
+        directory,
+        workspaceID: original.workspaceID,
+        title,
+      })
+      const msgs = yield* messages({ sessionID: input.sessionID })
+      const idMap = new Map<string, MessageID>()
+
+      for (const msg of msgs) {
+        if (input.messageID && msg.info.id >= input.messageID) break
+        const newID = MessageID.ascending()
+        idMap.set(msg.info.id, newID)
+
+        const parentID = msg.info.role === "assistant" && msg.info.parentID ? idMap.get(msg.info.parentID) : undefined
+        const cloned = yield* updateMessage({
+          ...msg.info,
+          sessionID: session.id,
+          id: newID,
+          ...(parentID && { parentID }),
+        })
+
+        for (const part of msg.parts) {
+          yield* updatePart({
+            ...part,
+            id: PartID.ascending(),
+            messageID: cloned.id,
+            sessionID: session.id,
+          })
+        }
+      }
+      return session
+    })
+
+    const patch = (sessionID: SessionID, info: Patch) =>
+      Effect.sync(() => SyncEvent.run(Event.Updated, { sessionID, info }))
+
+    const touch = Effect.fn("Session.touch")(function* (sessionID: SessionID) {
+      yield* patch(sessionID, { time: { updated: Date.now() } })
+    })
+
+    const setTitle = Effect.fn("Session.setTitle")(function* (input: { sessionID: SessionID; title: string }) {
+      yield* patch(input.sessionID, { title: input.title })
+    })
+
+    const setArchived = Effect.fn("Session.setArchived")(function* (input: { sessionID: SessionID; time?: number }) {
+      yield* patch(input.sessionID, { time: { archived: input.time } })
+    })
+
+    const setPermission = Effect.fn("Session.setPermission")(function* (input: {
+      sessionID: SessionID
+      permission: Permission.Ruleset
+    }) {
+      yield* patch(input.sessionID, { permission: input.permission, time: { updated: Date.now() } })
+    })
+
+    const setRevert = Effect.fn("Session.setRevert")(function* (input: {
+      sessionID: SessionID
+      revert: Info["revert"]
+      summary: Info["summary"]
+    }) {
+      yield* patch(input.sessionID, { summary: input.summary, time: { updated: Date.now() }, revert: input.revert })
+    })
+
+    const clearRevert = Effect.fn("Session.clearRevert")(function* (sessionID: SessionID) {
+      yield* patch(sessionID, { time: { updated: Date.now() }, revert: null })
+    })
+
+    const setSummary = Effect.fn("Session.setSummary")(function* (input: {
+      sessionID: SessionID
+      summary: Info["summary"]
+    }) {
+      yield* patch(input.sessionID, { time: { updated: Date.now() }, summary: input.summary })
+    })
+
+    const diff = Effect.fn("Session.diff")(function* (sessionID: SessionID) {
+      return yield* storage
+        .read<Snapshot.FileDiff[]>(["session_diff", sessionID])
+        .pipe(Effect.orElseSucceed((): Snapshot.FileDiff[] => []))
+    })
+
+    const messages = Effect.fn("Session.messages")(function* (input: { sessionID: SessionID; limit?: number }) {
+      if (input.limit) {
+        return MessageV2.page({ sessionID: input.sessionID, limit: input.limit }).items
+      }
+      return Array.from(MessageV2.stream(input.sessionID)).reverse()
+    })
+
+    const removeMessage = Effect.fn("Session.removeMessage")(function* (input: {
+      sessionID: SessionID
+      messageID: MessageID
+    }) {
+      yield* Effect.sync(() =>
+        SyncEvent.run(MessageV2.Event.Removed, {
+          sessionID: input.sessionID,
+          messageID: input.messageID,
+        }),
+      )
+      return input.messageID
+    })
+
+    const removePart = Effect.fn("Session.removePart")(function* (input: {
+      sessionID: SessionID
+      messageID: MessageID
+      partID: PartID
+    }) {
+      yield* Effect.sync(() =>
+        SyncEvent.run(MessageV2.Event.PartRemoved, {
+          sessionID: input.sessionID,
+          messageID: input.messageID,
+          partID: input.partID,
+        }),
+      )
+      return input.partID
+    })
+
+    const updatePartDelta = Effect.fn("Session.updatePartDelta")(function* (input: {
+      sessionID: SessionID
+      messageID: MessageID
+      partID: PartID
+      field: string
+      delta: string
+    }) {
+      yield* bus.publish(MessageV2.Event.PartDelta, input)
+    })
+
+    /** Finds the first message matching the predicate, searching newest-first. */
+    const findMessage = Effect.fn("Session.findMessage")(function* (
+      sessionID: SessionID,
+      predicate: (msg: MessageV2.WithParts) => boolean,
+    ) {
+      for (const item of MessageV2.stream(sessionID)) {
+        if (predicate(item)) return Option.some(item)
+      }
+      return Option.none<MessageV2.WithParts>()
+    })
+
+    return Service.of({
+      create,
+      fork,
+      touch,
+      get,
+      setTitle,
+      setArchived,
+      setPermission,
+      setRevert,
+      clearRevert,
+      setSummary,
+      diff,
+      messages,
+      children,
+      remove,
+      updateMessage,
+      removeMessage,
+      removePart,
+      updatePart,
+      getPart,
+      updatePartDelta,
+      findMessage,
+    })
+  }),
+)
+
+export const defaultLayer = layer.pipe(Layer.provide(Bus.layer), Layer.provide(Storage.defaultLayer))
+
+export function* list(input?: {
+  directory?: string
+  workspaceID?: WorkspaceID
+  roots?: boolean
+  start?: number
+  search?: string
+  limit?: number
+}) {
+  const project = Instance.project
+  const conditions = [eq(SessionTable.project_id, project.id)]
+
+  if (input?.workspaceID) {
+    conditions.push(eq(SessionTable.workspace_id, input.workspaceID))
+  }
+  if (input?.directory) {
+    conditions.push(eq(SessionTable.directory, input.directory))
+  }
+  if (input?.roots) {
+    conditions.push(isNull(SessionTable.parent_id))
+  }
+  if (input?.start) {
+    conditions.push(gte(SessionTable.time_updated, input.start))
+  }
+  if (input?.search) {
+    conditions.push(like(SessionTable.title, `%${input.search}%`))
+  }
+
+  const limit = input?.limit ?? 100
+
+  const rows = Database.use((db) =>
+    db
+      .select()
+      .from(SessionTable)
+      .where(and(...conditions))
+      .orderBy(desc(SessionTable.time_updated))
+      .limit(limit)
+      .all(),
+  )
+  for (const row of rows) {
+    yield fromRow(row)
+  }
+}
+
+export function* listGlobal(input?: {
+  directory?: string
+  roots?: boolean
+  start?: number
+  cursor?: number
+  search?: string
+  limit?: number
+  archived?: boolean
+}) {
+  const conditions: SQL[] = []
+
+  if (input?.directory) {
+    conditions.push(eq(SessionTable.directory, input.directory))
+  }
+  if (input?.roots) {
+    conditions.push(isNull(SessionTable.parent_id))
+  }
+  if (input?.start) {
+    conditions.push(gte(SessionTable.time_updated, input.start))
+  }
+  if (input?.cursor) {
+    conditions.push(lt(SessionTable.time_updated, input.cursor))
+  }
+  if (input?.search) {
+    conditions.push(like(SessionTable.title, `%${input.search}%`))
+  }
+  if (!input?.archived) {
+    conditions.push(isNull(SessionTable.time_archived))
+  }
+
+  const limit = input?.limit ?? 100
+
+  const rows = Database.use((db) => {
+    const query =
+      conditions.length > 0
+        ? db
+            .select()
+            .from(SessionTable)
+            .where(and(...conditions))
+        : db.select().from(SessionTable)
+    return query.orderBy(desc(SessionTable.time_updated), desc(SessionTable.id)).limit(limit).all()
+  })
+
+  const ids = [...new Set(rows.map((row) => row.project_id))]
+  const projects = new Map<string, ProjectInfo>()
+
+  if (ids.length > 0) {
+    const items = Database.use((db) =>
+      db
+        .select({ id: ProjectTable.id, name: ProjectTable.name, worktree: ProjectTable.worktree })
+        .from(ProjectTable)
+        .where(inArray(ProjectTable.id, ids))
+        .all(),
+    )
+    for (const item of items) {
+      projects.set(item.id, {
+        id: item.id,
+        name: item.name ?? undefined,
+        worktree: item.worktree,
+      })
+    }
+  }
+
+  for (const row of rows) {
+    const project = projects.get(row.project_id) ?? null
+    yield { ...fromRow(row), project }
+  }
+}