Two ways to make Opus 5 concise

Claude Code version 2.1.237 introduces a built-in Concise output style that trims verbose responses, replacing the need for custom ASD-STE100-based styles. In tests, the Concise style reduced a 663-word default response about the Olsen project's tech stack to a few sentences, while preserving full error output and detail on request. The style is one of five available via /output-style and changes only the default response length, not content accuracy.

Two ways to make Opus 5 concise Opus 5 is a strong coding model, but it answers every question with a word salad. My fix used to be a custom output style built on ASD-STE100, the simplified English of aircraft maintenance manuals. Now Claude Code ships a built-in style called Concise that does the same job better after changing one configuration. Load-bearing paragraphs Opus 5 at xhigh effort does excellent work. Then it tells you about it. And goes on an on. Ask for a variable rename and the answer explains which architectural “seam” the variable sits on, why that seam is “load-bearing”, and what is “worth knowing before you touch anything”. Every module is “the interesting part”. Somewhere in paragraph four, the rename is confirmed. The words are fine words on their own, there are just so many of them and they often make little sense together. Aircraft English ASD-STE100 is Simplified Technical English, the writing standard for aerospace maintenance manuals: a controlled dictionary of about 900 approved words, and rules that cap a sentence at 20 words with one instruction in it. It exists so a tired mechanic cannot misread a step. Exactly the reading level I want at the end of a long day. Claude Code supports custom output styles, and it will happily write one for itself. One prompt is enough: Change the output mode to use ASD-STE100 Claude wrote the style file to ~/.claude/output-styles/ASD-STE100.md , pointed the configuration at it, and added two carve-outs on its own: code and quoted text stay verbatim, and anything written for my projects follows my language guide instead of aerospace English. The new Concise style With version 2.1.237, Claude Code made the workaround unnecessary. /output-style now lists five styles, and the new one is Concise: “Claude responds tersely, leading with results and skipping preamble and narration.” An output style swaps the part of the system prompt that governs how Claude talks to you. Answers lead with the result and a simple question gets a sentence or three instead of a report. Narration and recaps are cut. Error output and failing tests keep their full content, and asking for detail still gets you detail. Only the default changes. Same question, three styles I tested all three in the repo of Olsen /apps/olsen/ , my crazy eights card game, asking each style to describe the project’s tech stack. Only the output style changed between runs. Default was the longest: "Here's what's actually in the project, checked against the Xcode project and the source rather than the docs." 663 words Here's what's actually in the project, checked against the Xcode project and the source rather than the docs. Shape of it One Xcode project, three native targets, ~18k lines of Swift: - olsen — the iPhone/iPad app, Mac Catalyst enabled TARGETED DEVICE FAMILY = "1,2" + SUPPORTS MACCATALYST = YES , com.hjerpbakk.olsen , version 2026.6 - olsen watchOS Watch App — com.hjerpbakk.olsen.watchkitapp , version 1.0 6 - olsenTests — unit tests Deployment targets are iOS 26.2 and watchOS 26.2. SWIFT VERSION = 5.0 , so Swift 5 language mode, but with SWIFT DEFAULT ACTOR ISOLATION = MainActor and SWIFT APPROACHABLE CONCURRENCY = YES : everything is main-actor by default and concurrency only shows up where it's asked for. MultiplayerSession.swift:11 spells out the consequence, that GameKit callbacks and sends all stay on the main thread so no hops are needed. UI layer, two of them Phone/iPad/Mac is a thin UIKit shell around SpriteKit. AppDelegate → SceneDelegate → Main storyboard → GameViewController , then everything visible is an SKScene : MainMenuScene , LobbyScene , OlsenGameScene 1410 lines, the biggest file , SettingsScene , HowToPlayScene , WelcomeScene , TutorialCompletionScene . Below those, hand-rolled SKNode subclasses in olsen/iOS/Nodes/ : CardNode , HandNode , DeckNode , SuitSelectorNode , ModernButtonNode , SFSymbolSprite , and CardGlowNode , which is the only place using SKShader . Card art comes out of Cards.spriteatlas through CardAtlas.swift , which caches the extracted textures. Mac Catalyst gets its own extras: a menu bar and a separate About window scene AboutSceneDelegate , routed by activity type in AppDelegate . The watch app is plain SwiftUI + WatchKit, no SpriteKit, with its own view models and models WatchGameViewModel , WatchModels . It is a separate implementation of the game's surface, not a port of the scenes. Game engine olsen/Shared/ is the platform-agnostic half: GameplayKit ECS with entities Player, Card, Deck, DiscardPile , components Hand, Turn, AI, Animation, Card, Sprite and systems CardPlay, Turn, Draw, AI . GameManager 878 lines is the singleton that owns the rules and pushes changes out through a delegate. AI is protocol-based, AIStrategy with Easy/Normal/Hard. Two protocol seams This is the interesting part of the architecture, and both seams are documented in their own files: - GameSession olsen/Shared/Session/GameSession.swift sits between the scene and the game. The scene talks to it instead of GameManager.shared , so the same scene renders either LocalGameSession a wrapper over the engine or RemoteGameSession a guest applying host snapshots . - GameTransport olsen/Shared/Multiplayer/GameTransport.swift sits between the game and the network. MultiplayerSession implements it over GKMatch ; the tests implement it with a fake. That's what keeps GameKit out of the engine and makes the snapshot fan-out unit-testable. Multiplayer is host-authoritative: SnapshotBroadcaster sends every remote seat its own redacted snapshot with a monotonic seq plus a baseline flag for reconnect resync, guests send intents GameIntent , seats are mapped in SeatMap , and invites come in via GKLocalPlayerListener and GameInviteRouter . Apple services Game Center is entitled on both the app and the watch: authentication, achievements, leaderboards, GKAccessPoint . The watch can't submit on its own, so WatchGameCenterManager relays through WCSession.sendUserInfo and GameCenterManager picks it up as a WCSessionDelegate GameCenterManager.swift:399 . StoreKit shows up in ReviewPrompter , SettingsScene and AboutViewController . Localization is String Catalogs Localizable.xcstrings , InfoPlist.xcstrings , en + nb. The app icon is the new Icon Composer format AppIcon.icon . Third-party, all SPM Three pins, no other package manager: - Google Mobile Ads 13.6.0 — interstitials only, through InterstitialAdManager , compiled out on Mac Catalyst - Google User Messaging Platform 3.1.0 — consent - umami-swift 1.6.0 — self-hosted analytics against hjerpbakk-analytics.fly.dev , imported in 25 files across both platforms, and skipped for test and -screenshotMode runs Tests olsenTests , Swift Testing import Testing , 8 files and almost all of it multiplayer: engine, snapshots, intents, seat map, broadcaster, remote session. The single-player engine has no direct coverage. Three things in AGENTS.md no longer match the project: there is no olsenUITests target only the three above , the Swift version is 5.0 rather than 6, and the preferred simulator listed there iPhone 16 Pro isn't installed on this machine any more, iPhone 17 Pro on 26.2 is. Also worth knowing: Info.plist sets NSAllowsArbitraryLoads true across the board, which is the ads-SDK boilerplate and wider than the app needs. ASD-STE100 trimmed it and used a simpler structure: " The stack in Olsen. Here's what the project actually is, from the sources rather than the docs." 525 words The stack in Olsen Here's what the project actually is, from the sources rather than the docs. Shell and build One Xcode project olsen.xcodeproj , no Package.swift . Three targets: olsen iPhone/iPad/Mac Catalyst , olsen watchOS Watch App , olsenTests . Two shared schemes. Around 18k lines of Swift. Language settings are worth knowing before you touch anything: SWIFT VERSION = 5.0 but with SWIFT DEFAULT ACTOR ISOLATION = MainActor and SWIFT APPROACHABLE CONCURRENCY = YES , so everything is main-actor by default and GameKit callbacks need no hops. Deployment targets are iOS 26.2 and watchOS 26.2, Catalyst on. The phone/iPad/Mac app A thin UIKit shell: AppDelegate → SceneDelegate → Main storyboard → GameViewController , which owns an SKView and picks the first scene based on tutorialCompleted and FirstLaunch.shouldShowWelcome . From there it is all SpriteKit: 7 scenes WelcomeScene , MainMenuScene , OlsenGameScene , LobbyScene , SettingsScene , HowToPlayScene , TutorialCompletionScene and 11 nodes CardNode , HandNode , DeckNode , SuitSelectorNode , CardGlowNode , and so on . The game engine GameplayKit ECS under olsen/Shared/ECS/ : - Entities: PlayerEntity , CardEntity , DeckEntity , DiscardPileEntity , all real GKEntity subclasses - Components: Hand , Turn , AI , Animation , Card , Sprite , all GKComponent - Systems: CardPlaySystem , TurnSystem , DrawSystem , AISystem , plain classes that GameManager owns and calls, not GKComponentSystem update loops GameManager.shared is the rules engine and pushes changes out through GameManagerDelegate . Deck shuffles through a GKRandomSource , so shuffles can be seeded. One correction to the docs: CLAUDE.md says game flow runs on a GKStateMachine . There is no state machine in the code. GamePhase is a plain enum and GameManager.currentPhase is derived from engine state on demand, with no stored field. Worth fixing in the doc at some point. AI is protocol-based: AIStrategy with EasyAI , NormalAI , HardAI . The two seams Both are documented in their own files, and they are the load-bearing part of the design: - GameSession sits between the scene and the game. The scene never touches GameManager.shared . LocalGameSession wraps the engine, RemoteGameSession applies host snapshots. SeatDescriptor lets the same avatar node render an AI or a human friend. - GameTransport sits between the game and the network. MultiplayerSession implements it over GKMatch , tests implement it with a fake. GameKit never reaches the engine. Multiplayer is host-authoritative: SnapshotBroadcaster sends each remote seat its own redacted snapshot only that seat's hand is populated with a monotonic seq plus a baseline flag for reconnect resync, guests send GameIntent s back, seats live in SeatMap , invites arrive through GameInviteRouter . watchOS Completely separate UI: SwiftUI + WatchKit, its own views and WatchGameViewModel , no SpriteKit. The watch cannot submit to Game Center on its own, so WatchGameCenterManager relays over WCSession.sendUserInfo to GameCenterManager on the phone. Dependencies Three SPM packages, all up-to-next-major: - googleads/swift-package-manager-google-mobile-ads 13.6.0 olsen target only - googleads/swift-package-manager-google-user-messaging-platform 3.1.0 olsen target only - hjerpbakk/umami-swift 1.6.0 both app targets Ads are interstitials only, behind InterstitialAdManager , compiled out on Catalyst. Umami is imported in 25 files, including the engine itself. Apple frameworks in play: SpriteKit, GameplayKit, GameKit, UIKit, SwiftUI, StoreKit the rating prompt via ReviewPrompter , AVFoundation and AudioToolbox AudioManager synthesizes its tones in code , WatchConnectivity, and Combine in exactly one file. Tests olsenTests , Swift Testing import Testing , 8 files and almost all of it multiplayer: engine, snapshots, intents, seat map, broadcaster, remote session. No UI test target. And Concise landed at half the default: "Native Apple stack, no cross-platform layer." 330 words Native Apple stack, no cross-platform layer. Three shipping surfaces from one repo: Platforms & build - Xcode project olsen.xcodeproj , two app targets: olsen iOS 26.2, iPad, Mac via Catalyst and olsen watchOS Watch App watchOS 26.2 . Tests in olsenTests + olsenUITests using Swift Testing import Testing , not XCTest. - Swift with SWIFT DEFAULT ACTOR ISOLATION = MainActor and approachable concurrency. Rendering - iOS/iPad/Mac: SpriteKit. GameViewController → SKScene subclasses in olsen/iOS/Scenes/ MainMenu, Lobby, Game, HowToPlay, Settings, Welcome, TutorialCompletion and hand-rolled SKNode subclasses in olsen/iOS/Nodes/ . Cards come from a sprite atlas Cards.spriteatlas via CardAtlas with texture caching. CardGlowNode uses an inline-GLSL SKShader with cached uniforms for the glow on special/playable cards. - watchOS: SwiftUI, a separate lightweight implementation WatchGameViewModel , WatchModels , WatchCardView rather than shared engine code. Game logic - GameplayKit ECS in olsen/Shared/ECS/ : entities Card, Deck, DiscardPile, Player , components Hand, Turn, AI, Animation, Card, Sprite , systems CardPlay, Turn, Draw, AI . GameManager 878 lines is the singleton coordinator that drives them and calls back through a delegate. - AI is protocol-based AIStrategy with Easy/Normal/Hard. - Note: CLAUDE.md says GKStateMachine handles game flow, but there is no GKStateMachine anywhere in the code. Flow lives in GameManager and the scenes. Multiplayer two seams - GameSession protocol is the seam between scene and game: LocalGameSession wraps the engine, RemoteGameSession renders host snapshots. The scene never touches GameManager.shared directly. - GameTransport is the seam between game and network: MultiplayerSession implements it over GKMatch , tests use a fake. Host authority with per-seat redacted GameSnapshot s fanned out by SnapshotBroadcaster with monotonic seq numbers, plus GameIntent / GameEvent , SeatMap , and GameInviteRouter . The engine never imports GameKit. - Watch talks to the phone over WatchConnectivity WCSession in GameCenterManager ↔ WatchGameCenterManager to relay Game Center. Dependencies SPM, iOS target only - Google Mobile Ads 13.6.0 + User Messaging Platform 3.1.0 InterstitialAdManager - umami-swift 1.6.0 — self-hosted analytics, imported in 25 files - Apple frameworks: GameKit Game Center, 20 achievements + leaderboard , StoreKit ReviewPrompter , AVFoundation/AudioToolbox AudioManager , UIKit haptics. Localization : String Catalogs Localizable.xcstrings , InfoPlist.xcstrings for English + Norwegian bokmål. All three name the same architecture and the same drift between my docs and the code. Nothing I needed is missing from the short one. Still Opus 5 is true to itself: even in Simplified Technical English or Concise mode, there will be seams.