spec/v1.0.0

## [1.0.0] — 2026-10-02

Spec version: `1.0.0`

### Added

- `AuthenticateParams.expiresIn` carries an OAuth access token's remaining lifetime in seconds.
- `SessionSummary.chats`, `SessionChatSummary.interactivity`, and `SessionSummary.defaultChat` expose lightweight chat navigation data without requiring a session subscription.
- `chat/isArchivedChanged` action for archiving a chat independently of its session.
- `ChatState.changesets` and `chat/changesetsChanged` expose each chat's changeset catalogue through the subscribed chat channel.
- `AutomationDefinition.disableConditions` supports `afterRuns` (`max`) and `afterDate` (`date`) rules combined with logical OR, with at most one condition per kind. Host-owned `AutomationEntry.runCount` tracks the current scheduled-run allowance. Edit conditions through `automation/updateRequested`: omission leaves them unchanged, an array replaces them, and `[]` removes all conditions without re-enabling the automation.
- `ChangesetStatus.Recomputing` distinguishes refreshes of a completed result from initial changeset computation.
- `ConfigPropertySchema.minItems` and `ConfigPropertySchema.maxItems` express array cardinality for `type: "array"` config properties. (#432)
- `McpServerStartingState.blocking` flag indicating that message processing may be held on the server, and the client-dispatchable `session/mcpServerBackgroundRequested` action asking the host to background such a startup.
- `AutomationSessionTemplate.customizations` lets automations carry client plugins (skills, agents, prompts, rules) that the host captures when the definition is saved, with the host-owned copies reported in `AutomationEntry.customizations` and support advertised by `AutomationCapabilities.customizations`.
- Hosts can advertise chat-owned canvas channel references and synchronize live presentation metadata and source URLs on experimental per-canvas channels.
- Atomic stable-URI `moveChat` transfer and same-session ordering for host-authorized chats, with per-chat `movable` discovery and durable authoritative catalogs.
- Expose chat-owned background work (background shells and subagents) in chat state, with `chat/backgroundWorkSet` and `chat/backgroundWorkRemoved` actions independent of turn lifetime.
- `ChatSummary.changes` and `ChatState.changes` provide aggregate file-change counts without requiring a changeset subscription.
- `SessionChatSummary.status` exposes per-chat archived state via `SessionStatus.IsArchived` in the lightweight chat catalog without requiring a session subscription.
- `chat/isReadChanged` action and optional `SessionChatSummary.status` projection for independently tracking the status of any known chat, including the default chat; the status bitset replaces the unreleased `isRead` and `archived` catalog fields.
- `SessionChatSummary.changes` exposes per-chat change counts in the lightweight chat catalog without requiring a session subscription.

### Changed

- Historical `ToolResultTerminalContent.resource` subscriptions return lazily reconstructed exited terminal state with retained output.
- `FileEdit` and preview `edits` now use named models in generated SDKs. This breaks affected SDK APIs but keeps JSON shapes unchanged.
- Advertise only the 1.0.0 and 0.9.0 protocol compatibility baselines independently of the development version. Host-side negotiation helpers select the highest client-offered version within either caret-compatible range and report malformed offers explicitly.