Patch release (2.1.241 → 2.1.245): a built-in MCP tool, richer Read/artifact results (including PDF page images), clearer cloud-session and computer-use behaviour, and expanded model/fast-mode guidance.
Changelog
[new] Built-in Mcp tool for working with MCP servers from the agent tool surface.
[new]Read can surface extracted PDF page images (with firstPage labeling) in the model-facing result, not only text/document payloads.
[new] Completing a Read on a saved Artifact source records which artifact version now counts as viewed (artifactRead).
[new] Nested/agent Read fan-out reports when images, failed page renders, or PDFs were dropped by per-result caps (imagesOmitted, imagePagesFailed, documentsOmitted, and related fields), so the model can say what was truncated.
[new] Scheduled/loop wakeups accept a required noop flag (unless stopping): consecutive no-op ticks collapse in the terminal and track as a streak, instead of looking like repeated empty activity.
[changed] Computer-use access flow: Finder is treated like any other app (desktop, Dock, Finder windows, Go to Folder need a Finder grant); menu bar stays available when the frontmost app is already granted. Clearer guidance when permissions are still missing, including teach-access retries via the desktop app.
[changed] Background task cancel can stop the worker’s in-flight work without killing the underlying process.
[changed] Plan-mode rejection handling: if feedback indicates the plan was teleported to the local terminal (__ULTRAPLAN_TELEPORT_LOCAL__), the agent acknowledges the teleport and does not keep implementing remotely.
[changed] Cloud/remote session behaviour: clearer messaging when files are still downloading, only exist in the session checkout, or when the user’s latest local edits may not have arrived yet; hooks/settings offered are those registered at attach time for writable session config.
[changed] Bug-report and publish-conflict copy tightened (evidence formatting, force-publish semantics on artifact pages).
[changed] Agent hand-back bookkeeping: optional harness section counts/hash and a handoffReviewSkipped marker so provenance frames stay aligned when auto-mode skips handoff review.
Models & prompts
Broader built-in model ID coverage, including additional Opus-family and related aliases used by routing and skills.
Migration guidance updated for fast mode: retired Opus 4.6/4.7 -fast / fast-speed paths must not remain in code—silent fallback or hard API errors depending on version—prefer current Opus 4.8 fast where fast mode is required.
Skills and system guidance refreshed for newer Opus/Sonnet behaviour (adaptive thinking, effort, image token costs, instruction-following, code-review harness tuning), Fable-tier model selection only when explicitly requested, and Bedrock’s requirement to disable thinking when forcing tool_choice.
Mid-conversation system messages preferred where supported so cached prefixes stay stable; dynamic context should not be stuffed into the frozen system prompt.
Design/frontend and Claude Design / design-system sync skills updated (scoped customization, Storybook package detection, anti-generic-UI defaults).
Subagent defaults clarified: background by default when available; don’t invent results before completion notifications.
Under the hood
Experimental and host-integration surface area expanded: local agents / agent teams, coordinator mode, directory/file sync (including git fast-forward workers), cloud plugin install/consent flows, device hooks, bridge reattach/heartbeat behaviour, and mobile emulator/simulator-related gates.
New settings and env knobs for prompt-cache TTL, fine-grained tool streaming, prompt suggestions, background plugin refresh, autocompact overrides, max tool-use concurrency, thinking disable, alternate-screen disable, artifact sync endpoints, and related host-managed auth/provider options.
SDK tool typings extended for remote-trigger/cron failure detail / server_message, loop noop, artifact reads, PDF page payloads, and internal hand-back provenance fields (marked unstable for external consumers).
Wrapper compatibility window refreshed (older tested wrapper versions dropped from the manifest list; newer ones included).
Binary size increased across platforms with the expanded embedded skill and runtime surface.
Upgrade notes
If you pinned retired fast-mode model strings (*-fast on older Opus IDs or speed: "fast" on paths that no longer accept it), update to supported Opus 4.8 fast-mode usage so you don’t hit silent slowdowns or hard API errors.
Re-baseline token budgets after model moves—especially image-heavy flows on newer Opus IDs—rather than reusing older max_tokens / context measurements.
Computer-use workflows that click the desktop, Dock, or Finder UI need an explicit Finder grant in the Claude desktop app on the machine running the session.
Consumers of agent tool results may see additional optional fields (omission counts, artifact view markers, harness provenance); treat internal harness_* fields as non-stable.
content/
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