Undocumented Items

This page lists everything that official Anthropic docs leave out. Each item carries the Undocumented badge on its own page. Here you find them all in one place, sorted by surface, with a link to the page that explains each one. An undocumented item can change or vanish in any release, so treat it with care.

Counts are table rows. A row can name several items, such as a list of related variables. Items that the docs name but describe wrongly are in Behaves Differently From the Docs.

Summary

Group	Count
Settings Keys	25
Environment Variables	868
CLI Flags and Subcommands	53
Permissions	121
Hooks	14
Commands	2
Skills	7
Subagents	7
Plugins	10
MCP	37
Tools	29
API Endpoints and Betas	54
System Prompt	34
Transcript and Sessions	16
Headless Protocol	155
Mod API	0
Other	110
Total	1542

Settings Keys

Keys for settings.json that no official page lists.

Count: 25.

Item	Where
`autoUploadSessions`	Agents and Remote Settings (Keys)
`daemonColdStart`	Agents and Remote Settings (Keys)
`doneMeansMerged`	Agents and Remote Settings (Keys)
`modelProposedGoals`	Agents and Remote Settings (Keys)
`remoteControl`	Agents and Remote Settings (Keys)
`remoteTools`	Agents and Remote Settings (Keys)
`skipWorkflowUsageWarning`	Agents and Remote Settings (Keys)
`xaaIdp`	Auth Settings (Keys)
`autoDreamEnabled`	Core Settings (Keys)
`precomputeCompactionEnabled`	Core Settings (Keys)
`todoFeatureEnabled`	Core Settings (Keys)
`policyHelpers`	Enterprise Settings (Keys)
`defaultView`	Extra Keys and Global Config (Auto Mode, Voice, and Display Keys)
`disablePluginDirectory`	Extra Keys and Global Config (Other Keys)
`isolation.required`	Extra Keys and Global Config (Other Keys)
`isolation.persistHome`	Extra Keys and Global Config (Other Keys)
`remoteControl.shareHostProfile`	Extra Keys and Global Config (Other Keys)
`remoteTools.allowUnattendedServing`	Extra Keys and Global Config (Other Keys)
`modelProposedGoals`, `feedbackDrafts`, `availableModelsMatch`, and 2 more	Settings Files and Scopes (Exceptions to Managed Precedence)
`totalTokensReminder`	Model Settings (Keys)
`totalTokensReminderAfterUserTurn`	Model Settings (Keys)
`totalTokensReminderBudget`	Model Settings (Keys)
`breakReminder`	Interface Settings (Keys)
`quietHours`	Interface Settings (Keys)
`showMessageTimestamps`	Interface Settings (Keys)

Environment Variables

There are too many to list one by one. Each page below holds a table, and every undocumented variable in it has the Undocumented badge. The pages sort variables by what they do.

Count: 868.

Page	Undocumented Rows
Agents and Teams	48
Auth and Accounts	42
Bundled Libraries	121
Cloud Providers	30
Context and Compaction	30
Features and Toggles	54
Models and Effort	31
Network and Proxy	22
Plugins and MCP	45
Remote and Cloud Sessions	98
SDK and Automation	21
Sessions and Storage	48
System and Third-Party	104
Telemetry and Debug	77
Tools and Bash	53
UI and Terminal	44

CLI Flags and Subcommands

Hidden or unlisted flags and subcommands.

Count: 53.

Item	Where
`--plugin-dir-no-mcp <path>`	Plugin Commands (Session Flags)
`--session-mirror`	All Flags (Start and Print Mode)
`--await-claim`	All Flags (Start and Print Mode)
`--await-initialize`	All Flags (Start and Print Mode)
`--sdk-url <url>`	All Flags (Start and Print Mode)
`--enable-auth-status`	All Flags (Start and Print Mode)
`--workload <tag>`	All Flags (Start and Print Mode)
`--client-data-url <url>`	All Flags (Start and Print Mode)
`--allow-other-models`	All Flags (Start and Print Mode)
`--managed-settings <json>`	All Flags (Start and Print Mode)
`--host-auth-is-org-sign-in`	All Flags (Start and Print Mode)
`-d2e, --debug-to-stderr`	All Flags (Safe Modes, Settings, and Debug)
`--project-config-root <dir>`	All Flags (Safe Modes, Settings, and Debug)
`--inherit-permission-mode <mode>`	All Flags (Permissions and Tools)
`--plan-mode-instructions <instructions>`	All Flags (Permissions and Tools)
`--thinking <mode>`	All Flags (Model and Thinking)
`--thinking-display <display>`	All Flags (Model and Thinking)
`--max-thinking-tokens <tokens>`	All Flags (Model and Thinking)
`--task-budget <tokens>`	All Flags (Model and Thinking)
`--fast-mode <on\|off>`	All Flags (Model and Thinking)
`--include-unsupported-models`	All Flags (Model and Thinking)
`--resume-session-at <message id>`	All Flags (Sessions and Worktrees)
`--resume-drops-turn <message id>`	All Flags (Sessions and Worktrees)
`--reply-on-resume`	All Flags (Sessions and Worktrees)
`--rewind-files <user-message-id>`	All Flags (Sessions and Worktrees)
`--plugin-dir-no-mcp <path>`	All Flags (Agents, Plugins, MCP, and Context)
`--brief`	All Flags (Agents, Plugins, MCP, and Context)
`--file <specs...>`	All Flags (Agents, Plugins, MCP, and Context)
`--watch-artifact <artifact>`	All Flags (Agents, Plugins, MCP, and Context)
`--watch-artifact-no-autoreact <artifact>`	All Flags (Agents, Plugins, MCP, and Context)
`--messaging-socket-path <path>`	All Flags (Agents, Plugins, MCP, and Context)
`--proactivity <level>`	All Flags (Agents, Plugins, MCP, and Context)
`--agent-id <id>`	All Flags (Teammate Flags)
`--agent-name <name>`	All Flags (Teammate Flags)
`--team-name <name>`	All Flags (Teammate Flags)
`--agent-color <color>`	All Flags (Teammate Flags)
`--plan-mode-required`	All Flags (Teammate Flags)
`--agent-type <type>`	All Flags (Teammate Flags)
`--parent-session-id <id>`	All Flags (Teammate Flags)
`--prefill <text>`	All Flags (IDE, Desktop, and Deep Links)
`--prefill-b64 <b64>`	All Flags (IDE, Desktop, and Deep Links)
`--deep-link-origin`	All Flags (IDE, Desktop, and Deep Links)
`--deep-link-repo <slug>`	All Flags (IDE, Desktop, and Deep Links)
`--deep-link-last-fetch <ms>`	All Flags (IDE, Desktop, and Deep Links)
`--deep-link-cwd-b64 <b64>`	All Flags (IDE, Desktop, and Deep Links)
`--pool <pool_id>`	All Flags (Cloud and Remote Sessions)
`--correlation-id <id>`	All Flags (Cloud and Remote Sessions)
`--on-branch <branch>`	All Flags (Cloud and Remote Sessions)
`--forward-home-settings <true\|false>`	All Flags (Cloud and Remote Sessions)
`--attach-serve <session_id>`	All Flags (Cloud and Remote Sessions)
`claude sandbox`	Subcommands (Commands)
`claude edit-hook`, `edit-permission-rules`, `edit-memory-settings`, and 5 more	Subcommands (Commands)
`claude import-conversations <exportPath>`	Subcommands (Commands)

Permissions

Auto mode rules, permission modes, rule syntax, and the sandbox.

Count: 121.

The 85 default auto mode rules are all listed on Auto Mode Default Rules. They are not repeated here.

Item	Where
`CLAUDE_CODE_AUTO_MODE_MODEL`	Auto Mode (Environment Variables)
`CLAUDE_CODE_BG_CLASSIFIER_MODEL`	Auto Mode (Environment Variables)
`CLAUDE_CODE_AUTO_MODE_TIER`	Auto Mode (Environment Variables)
`CLAUDE_CODE_CLASSIFIER_SUMMARY`	Auto Mode (Environment Variables)
`CLAUDE_CODE_TWO_STAGE_CLASSIFIER`	Auto Mode (Environment Variables)
`CLAUDE_CODE_AUTO_MODE_EXTERNAL_PERMISSIONS`	Auto Mode (Environment Variables)
`CLAUDE_CHROME_CLASSIFIER_FLOOR`, `CLAUDE_CHROME_PERMISSION_MODE`	Auto Mode (Environment Variables)
`CLAUDE_BG_SESSION_PERMISSION_RULES`	Auto Mode (Environment Variables)
`CLAUDE_CODE_PARKED_PERMISSION_WAIT_MS`	Auto Mode (Environment Variables)
`CLAUDE_CODE_RESTRICT_PERSONAL_CONFIG`	Auto Mode (Environment Variables)
`rule`	Permission Modes (Decision Reasons)
`mode`	Permission Modes (Decision Reasons)
`subcommandResults`	Permission Modes (Decision Reasons)
`permissionPromptTool`	Permission Modes (Decision Reasons)
`hook`	Permission Modes (Decision Reasons)
`asyncAgent`	Permission Modes (Decision Reasons)
`sandboxOverride`	Permission Modes (Decision Reasons)
`workingDir`	Permission Modes (Decision Reasons)
`safetyCheck`	Permission Modes (Decision Reasons)
`classifier`	Permission Modes (Decision Reasons)
`other`	Permission Modes (Decision Reasons)
`dangerousRemoval`	Permission Modes (Safety Checks)
`backgroundOperator`	Permission Modes (Safety Checks)
`suspiciousWindowsPath`	Permission Modes (Safety Checks)
`restrictedMode`	Permission Modes (Safety Checks)
`outsideReadsBlocked`	Permission Modes (Safety Checks)
`claudeSettingsFile`	Permission Modes (Safety Checks)
`internalHardDeny`	Permission Modes (Safety Checks)
`unfinishedCheck`	Permission Modes (Safety Checks)
`mcp__server`, `mcp__server__tool`	Permission Rules (Rule Syntax)
`sandbox.ripgrep.command`, `sandbox.ripgrep.args`	Sandbox (Core Keys)
`CLAUDE_CODE_BASH_SANDBOX_SHOW_INDICATOR`	Sandbox (Environment Variables)
`IS_SANDBOX`	Sandbox (Environment Variables)
`CLAUDE_CODE_SANDBOXED`	Sandbox (Environment Variables)
`CLAUDE_CODE_SANDBOX_LEAVE_PARENT_FOLDERS_ALONE`	Sandbox (Environment Variables)
`CLAUDE_CODE_SANDBOX_LEAVE_DENIES_TO_SRT_WIN`	Sandbox (Environment Variables)

Hooks

Hook settings, events, fields, and handler types.

Count: 16.

Item	Where
`asyncTimeout`	Hook Configuration (Timeouts)
`onFailure` has no effect	Hook Configuration (Failure Handling)
`CLAUDE_CODE_RESTRICT_PERSONAL_CONFIG`	Hook Configuration (Failure Handling)
`CLAUDE_CODE_HOOKS_SAME_THREAD`	Hook Configuration (Environment Variables for Hooks)
`CLAUDE_CODE_DISABLE_HOOK_FORWARDING`	Hook Configuration (Environment Variables for Hooks)
`CLAUDE_CODE_RESUME_SESSIONSTART_HOOKS_WAIT_MS`	Hook Configuration (Environment Variables for Hooks)
`DISABLE_BRIEF_MODE_STOP_HOOK`	Hook Configuration (Environment Variables for Hooks)
`permissionDisplay`	Hook Events (PreToolUse)
`source`	Hook Events (UserPromptSubmit)
`auth_storage_failure`, `computer_use_enter`, `computer_use_exit`, and 3 more	Hook Events (Notification)
`callback`	Hook Handlers (Handler Types)
`rewakeMessage`	Hook Handlers (Command Fields)
`rewakeSummary`	Hook Handlers (Command Fields)
`cloud`	Hook Handlers (Command Fields)
SDK callback hooks	Hooks (Where Hooks Are Defined)
`{"async":true,"asyncTimeout":n}`	Hook Input and Output (Universal Output Fields)

Commands

Slash commands that no official page lists.

Count: 2.

Item	Where
`/pro-trial-expired`	Slash Commands (Account, Cloud, and Other Commands)
`/daemon`	Slash Commands (Account, Cloud, and Other Commands)

Skills

Skill frontmatter, bundled skills, and substitutions.

Count: 7.

Item	Where
`/keybindings-help`	Bundled Skills (Skills)
`created_by`, `improved_by`	Skill Frontmatter (Keys)
MCP-served skill	Skills and Commands (Skill Locations)
Skill `loadedFrom` values	Skills and Commands (Skill Locations)
Name length	Skills and Commands (Name Resolution)
Total size cap	Substitutions and Invocation (String Substitutions)
Commit-time skills	Substitutions and Invocation (Invocation Control)

Subagents

Frontmatter keys and built-in agents that official pages leave out.

Count: 7.

Item	Where
`observer`	Subagent Frontmatter (Keys)
`observerMessage`	Subagent Frontmatter (Keys)
`observeSubagents`	Subagent Frontmatter (Keys)
`workflow-subagent`	Subagent Runtime (Built-In Agents)
`comment-thread-analyst`	Subagent Runtime (Built-In Agents)
Web-reading agent	Subagent Runtime (Built-In Agents)
`CLAUDE_CODE_ENABLE_APPEND_SUBAGENT_PROMPT`, `CLAUDE_CODE_MEMORY_SUBAGENT_APPEND`, `CLAUDE_CODE_SUBAGENT_PROMPT_SNAPSHOT`, and 2 more	Subagent Runtime (Limits and Switches)

Plugins

Manifest keys, cache files, and plugin switches.

Count: 10.

Item	Where
`--plugin-dir-no-mcp <path>`	Plugin Commands (Session Flags)
`plugins/cache/<marketplace>/<plugin>/<version>/`	Plugin Loading (Paths)
`plugins/installed_plugins.json`	Plugin Loading (Paths)
`plugins/known_marketplaces.json`	Plugin Loading (Paths)
`installed`, `marketplaces`, `flagged`, and 2 more	Plugin Loading (Paths)
`CLAUDE_CODE_PLUGIN_USE_ZIP_CACHE`, `CLAUDE_CODE_PLUGIN_BINARY_ASSETS`, `CLAUDE_CODE_PLUGIN_ATTRIBUTION`, and 2 more	Plugin Loading (Env Vars)
`CLAUDE_CODE_SKIP_PLUGIN_MCP_SERVERS`, `CLAUDE_CODE_SKIP_PLUGIN_MCP_SERVERS_EXCEPT`, `CLAUDE_CODE_SKIP_PLUGIN_LOCAL_MCP_SERVERS`, `CLAUDE_CODE_SKIP_PLUGIN_MCP_BUNDLES`	Plugin Loading (Env Vars)
`experimental.syntaxHighlighting.hljsLanguages`	Plugin Manifest (Top-Level Keys)
`binaries`	Plugin Manifest (Top-Level Keys)
`unsupported`	Marketplaces (Plugin Sources)

MCP

Server types, scopes, options, and variables for MCP.

Count: 37.

Item	Where
`MCP_OAUTH_CLIENT_METADATA_URL`	MCP Authentication (OAuth Options)
`bareElicitationCapability`	Server Configuration (Server Options)
`discoveryCache`	Server Configuration (Server Options)
`request_timeout_ms`	Server Configuration (Server Options)
`toolPermissions`	Server Configuration (Server Options)
`disableAutoBackground`	Server Configuration (Server Options)
`ideName`, `ideRunningInWindows`, `authToken`	Server Configuration (Server Options)
`cachedInitResponse`, `cachedDiscoverResponse`, `discoverSupport`, and 2 more	Server Configuration (Server Options)
Blocked names	Server Configuration (Names)
`ENABLE_MCP_LARGE_OUTPUT_FILES`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_MCP_APPS_HOST`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_SKIP_PLUGIN_MCP_SERVERS`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_SKIP_PLUGIN_MCP_SERVERS_EXCEPT`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_SKIP_PLUGIN_LOCAL_MCP_SERVERS`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_SKIP_PLUGIN_MCP_BUNDLES`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_ENABLE_REFRESH_MCP_TOOLS`	MCP Env Vars (Undocumented Variables)
`MCP_TRUNCATION_PROMPT_OVERRIDE`	MCP Env Vars (Undocumented Variables)
`MCP_OAUTH_CLIENT_METADATA_URL`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_SYNC_PLUGINS_MCP_TIMEOUT_MS`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_MCP_CONNECTOR_PREWAIT_MS`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_MCP_PREWAIT_SERVERS`, `CLAUDE_CODE_MCP_PREWAIT_SERVERS_MS`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_MCP_MEMORY_CGROUP`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_TERMINAL_MCP_TOOLS`	MCP Env Vars (Undocumented Variables)
`CLAUDE_AGENT_SDK_DISABLE_MCP_MANIFESTS`	MCP Env Vars (Undocumented Variables)
`CLAUDE_CODE_BRIDGE_MCP_CARRIER`	MCP Env Vars (Undocumented Variables)
`sse-ide`	MCP (Transports)
`ws-ide`	MCP (Transports)
`claudeai-proxy`	MCP (Transports)
`dynamic`	MCP (Scopes)
`enterprise`, `agent`	MCP (Scopes)
`SearchMcpRegistry`, `SuggestConnectors`, `ListConnectors`	MCP Runtime (Tools and Names)
`ReadMcpResourceDirTool`	MCP Runtime (Resources and Prompts)
Old tool names	MCP Runtime (Resources and Prompts)
`CLAUDE_CODE_MCP_APPS_HOST`	MCP Runtime (Resources and Prompts)
`ENABLE_MCP_LARGE_OUTPUT_FILES`	MCP Runtime (Limits)
`xaaIdp`	MCP Settings and Policy (Settings Keys)
`--plugin-dir-no-mcp <path>`	MCP Settings and Policy (Files and Flags)

Tools

Tools and tool parameters.

Count: 29.

Item	Where
`ProposeGoal`	Agents, Tasks, and Planning (Tools)
`memory_read`	Files, Search, and Memory (Tools)
`memory_write`	Files, Search, and Memory (Tools)
`memory_list`	Files, Search, and Memory (Tools)
`ReadNotifications`	Gated and Surface-Specific Tools (Gated Tools)
`ShowOnboardingRolePicker`	Gated and Surface-Specific Tools (Gated Tools)
`OfferChromeSetup`	Gated and Surface-Specific Tools (Gated Tools)
`SendUserMessage`	Gated and Surface-Specific Tools (Gated Tools)
`SuggestPluginInstall`	Gated and Surface-Specific Tools (Gated Tools)
`SuggestSkills`	Gated and Surface-Specific Tools (Gated Tools)
`FetchInboxMessage`	Gated and Surface-Specific Tools (Gated Tools)
`PublishPlugin`	Gated and Surface-Specific Tools (Gated Tools)
`AppifactRepl`	Gated and Surface-Specific Tools (Gated Tools)
`SendFile`	Gated and Surface-Specific Tools (Gated Tools)
`DesignSync`	Gated and Surface-Specific Tools (Gated Tools)
`ClaudeDesign`	Gated and Surface-Specific Tools (Gated Tools)
`Projects`	Gated and Surface-Specific Tools (Gated Tools)
`SearchMcpRegistry`	Gated and Surface-Specific Tools (Gated Tools)
`SuggestConnectors`	Gated and Surface-Specific Tools (Gated Tools)
`ListConnectors`	Gated and Surface-Specific Tools (Gated Tools)
`propose_skills`	Gated and Surface-Specific Tools (Gated Tools)
`StructuredOutput`	Gated and Surface-Specific Tools (Tools without an Inventory Row)
Query `select:A,B`	Tools (ToolSearch)
Query keywords	Tools (ToolSearch)
Query `+term rest`	Tools (ToolSearch)
Placeholder tool	Tools (ToolSearch)
Server-side never-defer list	Tools (Switches for Tool Search)
Server-side defer list	Tools (Switches for Tool Search)
`GetTask`	Shell, Web, and Background Tasks (Tools)

API Endpoints and Betas

Endpoints that Claude Code calls and the beta headers it sends.

Count: 54.

Item	Where
`claude-code-20250219`	Betas (Registry)
`oauth-2025-04-20`	Betas (Registry)
`context-1m-2025-08-07`	Betas (Registry)
`context-management-2025-06-27`	Betas (Registry)
`structured-outputs-2025-12-15`	Betas (Registry)
`web-search-2025-03-05`	Betas (Registry)
`advanced-tool-use-2025-11-20`	Betas (Registry)
`tool-search-tool-2025-10-19`	Betas (Registry)
`effort-2025-11-24`	Betas (Registry)
`task-budgets-2026-03-13`	Betas (Registry)
`prompt-caching-scope-2026-01-05`	Betas (Registry)
`prompt-caching-evict-2026-05-12`	Betas (Registry)
`cache-keepalive-2026-09-03`	Betas (Registry)
`fast-mode-2026-02-01`	Betas (Registry)
`redact-thinking-2026-02-12`	Betas (Registry)
`thinking-resumption-2026-07-17`	Betas (Registry)
`thinking-token-count-2026-05-13`	Betas (Registry)
`afk-mode-2026-01-31`	Betas (Registry)
`advisor-tool-2026-03-01`	Betas (Registry)
`cache-diagnosis-2026-04-07`	Betas (Registry)
`context-hint-2026-04-09`	Betas (Registry)
`mcp-servers-2025-12-04`	Betas (Registry)
`files-api-2025-04-14`	Betas (Registry)
`environments-2025-11-01`	Betas (Registry)
`per-turn-control-2026-07-01`	Betas (Registry)
`timing-2026-09-09`	Betas (Registry)
`mid-conversation-tool-changes-2026-07-01`	Betas (Registry)
`inline-tools-2026-09-15`	Betas (Registry)
`server-side-fallback-2026-06-01`	Betas (Registry)
`server-side-fallback-2026-07-01`	Betas (Registry)
`fallback-credit-2026-06-01`	Betas (Registry)
`auto-mode-classifier-2026-07-16`	Betas (Registry)
`dangerous-tool-use-2026-09-03`	Betas (Registry)
`thinking-display-updates-2026-08-18`	Betas (Registry)
`thinking-binding-controls-2026-08-01`	Betas (Registry)
`message-threads-2026-08-12`	Betas (Registry)
`mid-conversation-system-clear-at-2026-08-21`	Betas (Registry)
`/v1/messages/cache_touch`	Endpoints and Headers (Model Endpoints)
`/v1/oauth/token`, `/api/oauth/profile`, `/api/oauth/usage`, `/api/oauth/account/settings`	Endpoints and Headers (Account and Service Endpoints)
`/api/claude_code/policy_limits`	Endpoints and Headers (Account and Service Endpoints)
`/api/claude_code/organizations/metrics_enabled`, `/api/claude_code/notification/preferences`, `/api/claude_code/skills`	Endpoints and Headers (Account and Service Endpoints)
`/api/event_logging/v2/batch`	Endpoints and Headers (Account and Service Endpoints)
`/api/claude_cli_feedback`, `/api/claude_code_shared_session_transcripts`	Endpoints and Headers (Account and Service Endpoints)
`/v1/code/sessions`, `/v1/code/triggers`, `/v1/code/github/*`, `/v1/code/agent-proxy`	Endpoints and Headers (Account and Service Endpoints)
`/v1/ultrareview/quota`, `/v1/ultrareview/preflight`	Endpoints and Headers (Account and Service Endpoints)
`/api/model_selector/{id}`, `/api/organization/claude_code_first_token_date`	Endpoints and Headers (Account and Service Endpoints)
`/api/ws/speech_to_text/voice_stream`	Endpoints and Headers (Account and Service Endpoints)
`/api/frame/`, `/v1/design/`	Endpoints and Headers (Account and Service Endpoints)
`x-app`, `anthropic-client-platform`, `X-Stainless-*`, and 2 more	Endpoints and Headers (Request Headers)
`cc_version`	Endpoints and Headers (Attribution Block)
`cc_entrypoint`	Endpoints and Headers (Attribution Block)
`cc_workload`, `cc_is_subagent`	Endpoints and Headers (Attribution Block)
`cc_prev_req`, `cc_prompt_id`, `cc_turn_origin`, and 2 more	Endpoints and Headers (Attribution Block)
`cc_gateway`, `cc_project`, `cc_project_src`	Endpoints and Headers (Attribution Block)

System Prompt

How the prompt is built, plus the captured prompt variants.

Count: 34.

Item	Where
Haiku 5.5 by default	The System Prompt (Short or Full Prompt)
Billing header line	The System Prompt (Where Each Part Goes in the Request)
Identity line	The System Prompt (Where Each Part Goes in the Request)
Rules, memory section, appended text	The System Prompt (Where Each Part Goes in the Request)
Environment details, skills list, agent types, output style text, the date	The System Prompt (Where Each Part Goes in the Request)
Git status, `CLAUDE.md` files, the git attribution reminder	The System Prompt (Where Each Part Goes in the Request)
`--permission-mode acceptEdits`, `dontAsk`, `--brief`	The System Prompt (What Each Flag Does in the Captures)
`lean_body`	The System Prompt (Shared Sections)
`intro`	The System Prompt (Shared Sections)
`system`	The System Prompt (Shared Sections)
`doing_tasks`	The System Prompt (Shared Sections)
`actions`	The System Prompt (Shared Sections)
`tools`	The System Prompt (Shared Sections)
`tone`	The System Prompt (Shared Sections)
`memory_static`	The System Prompt (Shared Sections)
`communication`	The System Prompt (Session Sections)
`pronouns`	The System Prompt (Session Sections)
`action_caution`	The System Prompt (Session Sections)
`fable_identity`	The System Prompt (Session Sections)
`session_guidance`	The System Prompt (Session Sections)
`memory`	The System Prompt (Session Sections)
`env_info_simple`	The System Prompt (Session Sections)
`env_info_static`	The System Prompt (Session Sections)
`context_management`	The System Prompt (Session Sections)
`brief`	The System Prompt (Session Sections)
`focus_mode`	The System Prompt (Session Sections)
Default, Lean Prompt	Captured System Prompts (All Variants)
Default, Haiku 5.5	Captured System Prompts (All Variants)
Inside a Git Repository	Captured System Prompts (All Variants)
Brief Mode (same text as default-lean)	Captured System Prompts (All Variants)
Compaction Prompt	Captured System Prompts (All Variants)
Subagent, General Purpose	Captured System Prompts (All Variants)
Subagent, Explore	Captured System Prompts (All Variants)
Subagent, Plan	Captured System Prompts (All Variants)

Transcript and Sessions

Records in the transcript file and how sessions are stored.

Count: 16.

Item	Where
`--resume-session-at <message id>`	Sessions and Storage (Resume and Branch)
`--reply-on-resume`	Sessions and Storage (Resume and Branch)
`--rewind-files <user-message-id>`	Sessions and Storage (Resume and Branch)
`state/`, `mods/`, `bridge-spawn/`, and 3 more	Sessions and Storage (Where Files Live)
`type`	Transcript Format (Common Fields)
`uuid`	Transcript Format (Common Fields)
`parentUuid`	Transcript Format (Common Fields)
`sessionId`	Transcript Format (Common Fields)
`timestamp`	Transcript Format (Common Fields)
`cwd`	Transcript Format (Common Fields)
`gitBranch`	Transcript Format (Common Fields)
`version`	Transcript Format (Common Fields)
`entrypoint`	Transcript Format (Common Fields)
`userType`	Transcript Format (Common Fields)
`isSidechain`	Transcript Format (Common Fields)
`isMeta`	Transcript Format (Common Fields)

Headless Protocol

Message types of --output-format stream-json and of the control protocol. Nearly every row is undocumented, so this page links to the two pages with counts.

Count: 155.

Page	Undocumented Rows
Control Protocol	91
Stream JSON Messages	64

Mod API

The Mod API is covered by official Mods pages, so no Mod API item is listed here as undocumented. Differences are in the last section. For the Mod API, Documented means that the item is in the official docs or in the published type file (which the docs call "The complete reference"), so the Mod API shows 0 Undocumented rows.

Count: 0.

Other

Items that fit no group above: memory, output styles, the status line, models, and how the harness works inside.

Count: 110.

Item	Where
`autoDreamEnabled`	Memory and Rules (Auto Memory)
`/pause-memory`	Memory and Rules (Auto Memory)
`CLAUDE_CODE_REMOTE_MEMORY_DIR`, `CLAUDE_CODE_POST_TURN_MEMORY`, `CLAUDE_COWORK_MEMORY_*`, `CLAUDE_MEMORY_STORES`	Memory and Rules (Auto Memory)
`InstructionFileKind`	Memory and Rules (The InstructionsLoaded Hook)
`--include-unsupported-models`	Models and Providers (Choose a Model)
`claude-3-5-haiku`	Models and Providers (Catalog)
`claude-3-5-sonnet`	Models and Providers (Catalog)
`claude-3-7-sonnet`	Models and Providers (Catalog)
`claude-sonnet-4-0`	Models and Providers (Catalog)
`claude-opus-4-0`	Models and Providers (Catalog)
`claude-mythos-5-1`	Models and Providers (Catalog)
`--thinking <enabled\|adaptive\|disabled>`	Models and Providers (Thinking)
`--thinking-display <summarized\|omitted\|highlights>`	Models and Providers (Thinking)
`--max-thinking-tokens`	Models and Providers (Thinking)
`CLAUDE_CODE_NO_MODEL_FALLBACK`	Models and Providers (Fallback and Retries)
`CLAUDE_CODE_USE_ANTHROPIC_GOOGLE_CLOUD`	Models and Providers (Providers)
`CLAUDE_CODE_USE_GATEWAY`	Models and Providers (Providers)
`ANTHROPIC_GOOGLE_CLOUD_BASE_URL`, `_LOCATION`, `_PROJECT`, `_WORKSPACE_ID`	Models and Providers (Endpoint and Region Variables)
`CLAUDE_CODE_SKIP_ANTHROPIC_GOOGLE_CLOUD_AUTH`	Models and Providers (Endpoint and Region Variables)
`claude-3-5-haiku`	Models and Providers (Provider Names)
`claude-3-5-sonnet`	Models and Providers (Provider Names)
`claude-3-7-sonnet`	Models and Providers (Provider Names)
`claude-sonnet-4-0`	Models and Providers (Provider Names)
`claude-opus-4-0`	Models and Providers (Provider Names)
`claude-mythos-5-1`	Models and Providers (Provider Names)
Custom style over Remote Control	Output Styles (The outputStyle Setting and Switching)
`outputStylesPath`, `outputStylesPaths`	Output Styles (Locations and Precedence)
Merge order	Output Styles (Locations and Precedence)
`remote.session_id`	Status Line (Session and Model Fields)
4. Message prep	The Agent Loop (The Stages)
6. Attachments	The Agent Loop (The Stages)
10. Next round	The Agent Loop (The Stages)
The output stops at `max_tokens`	The Agent Loop (Recovery Inside the Loop)
The response is cut off	The Agent Loop (Recovery Inside the Loop)
A `tool_use` block has no valid call	The Agent Loop (Recovery Inside the Loop)
The model sends only thinking	The Agent Loop (Recovery Inside the Loop)
Bundled code	Architecture (The Big Picture)
Command parser	Architecture (The Big Picture)
Terminal screen	Architecture (The Big Picture)
Feature flags	Architecture (The Big Picture)
`mcp`	Architecture (Where It Runs)
`claude-code-github-action`	Architecture (Where It Runs)
`local-agent`, `claude-desktop`, `remote`	Architecture (Where It Runs)
Start	Architecture (Startup Steps)
Device settings	Architecture (Startup Steps)
Project root	Architecture (Startup Steps)
Init	Architecture (Startup Steps)
Client data	Architecture (Startup Steps)
Log sinks	Architecture (Startup Steps)
Plugin folders	Architecture (Startup Steps)
Migrations	Architecture (Startup Steps)
Managed settings	Architecture (Startup Steps)
Plugin early start	Architecture (Startup Steps)
Main action	Architecture (Startup Steps)
MCP connect	Architecture (Startup Steps)
Print mode	Architecture (Startup Steps)
Interactive mode	Architecture (Startup Steps)
See how long each startup step takes	Architecture (What You Can Change at Startup)
Attachments that Claude Code adds	Context and Compaction (What Fills the Context)
Effective window	Context and Compaction (When Compaction Runs)
Warning	Context and Compaction (When Compaction Runs)
Blocked	Context and Compaction (When Compaction Runs)
Reactive	Context and Compaction (Kinds of Compaction)
Precomputed	Context and Compaction (Kinds of Compaction)
Larger-model retry	Context and Compaction (Kinds of Compaction)
Server side	Context and Compaction (Kinds of Compaction)
`--include-unsupported-models`	Models (Choosing the Model)
`per-turn-control-2026-07-01`	Models (Effort)
`--thinking <enabled\|adaptive\|disabled>`	Models (Thinking)
`--thinking-display <summarized\|omitted\|highlights>`	Models (Thinking)
`--max-thinking-tokens`	Models (Thinking)
`context_management`	Models (Capabilities)
`effort`	Models (Capabilities)
`max_effort`	Models (Capabilities)
`xhigh_effort`	Models (Capabilities)
`adaptive_thinking`	Models (Capabilities)
`mid_conv_tool_change`	Models (Capabilities)
`rejects_disabled_thinking`	Models (Capabilities)
`per_turn_effort`	Models (Capabilities)
`per_turn_timing`	Models (Capabilities)
`lean_prompt`	Models (Capabilities)
`org_locked_thinking`	Models (Capabilities)
`haiku_5_5_early_stopping_guidance`	Models (Capabilities)
`refusal_fallback`	Models (Capabilities)
`silent_turn_reminder`	Models (Capabilities)
`fast_mode`	Models (Capabilities)
`thinking_disabled_effort_cap`	Models (Capabilities)
`opus_5_prompt_bundle`	Models (Capabilities)
`opus_5_5_prompt_bundle`	Models (Capabilities)
`fable_5_mitigations`	Models (Capabilities)
`fable_5_1_prompt_bundle`	Models (Capabilities)
`safeguards`	Request and Cache (Body Fields)
`system[0]` (attribution line)	Request and Cache (System Blocks and Cache Markers)
`system[1]` (identity line)	Request and Cache (System Blocks and Cache Markers)
`system[2]` (system prompt)	Request and Cache (System Blocks and Cache Markers)
Last block of the last message	Request and Cache (System Blocks and Cache Markers)
`DISABLE_PROMPT_CACHING_MYTHOS`	Request and Cache (Cache Lifetime)
`CLAUDE_CODE_MESSAGES_PROMPT_CACHE_TTL`	Request and Cache (Cache Lifetime)
`--model X[1m]`	Probes (Effects and Differences)
`CLAUDE_CODE_AMBER_ASTROLABE`	Probes (Effects and Differences)
`CLAUDE_CODE_BASALT_COVE`	Probes (Effects and Differences)
`CLAUDE_CODE_HUMBLE_HAMMOCK`	Probes (Effects and Differences)
`CLAUDE_CODE_INLINE_TOOLS`	Probes (Effects and Differences)
`CLAUDE_CODE_LANTERN_PRISM`	Probes (Effects and Differences)
`CLAUDE_CODE_LARCH_CISTERN`	Probes (Effects and Differences)
`CLAUDE_CODE_PLUGIN_DIRS`	Probes (Effects and Differences)
`CLAUDE_CODE_SIMULATE_PROXY_USAGE`	Probes (Effects and Differences)
`CLAUDE_CODE_SKIP_PLUGIN_MCP_SERVERS`	Probes (Effects and Differences)
`CLAUDE_CODE_SYNC_PLUGIN_INSTALL`	Probes (Effects and Differences)
`CLAUDE_CODE_USE_COWORK_PLUGINS`	Probes (Effects and Differences)

Behaves Differently From the Docs

These items exist in the official docs, but the program works in another way. Count: 42. The badge on each page says how.

Item	Where
`disallowedTools`	Subagent Frontmatter (Keys)
`effort`	Skill Frontmatter (Keys)
`next.error`	Hooks and the Hook Chain (Arguments of a Hook)
`prompt.edit` hook time	Hooks and the Hook Chain (Budgets)
`vscode`	Surfaces, Elements, and Render Sites (Surfaces)
Error type	Hook Configuration (Matcher Targets)
`disableAllHooks`	Hook Configuration (Settings Keys and Trust)
Top-level `decision` and `reason`	Hook Events (PreToolUse)
`destination`	Hook Events (Permission Update Entries)
`additionalContext`	Hook Events (Setup)
`error`	Hook Events (StopFailure)
`script`	Hook Handlers (Handler Types)
`model`	Hook Handlers (Prompt and Agent Fields)
`scratchpad_dir`	Hook Input and Output (Common Input Fields)
`decision`	Hook Input and Output (Universal Output Fields)
`autoMemoryDirectory` scope	Memory and Rules (Auto Memory)
Model, fast mode, effort, thinking, and PR status change	Status Line (When the Script Runs)
`appendPlugins`	Hooks, Plugins, and Skills Settings (Keys)
`prependPlugins`	Hooks, Plugins, and Skills Settings (Keys)
`CLAUDE_CODE_ARTIFACT_COMMENTS`	Features and Toggles (Variables)
`CLAUDE_CODE_ARTIFACT_COMMENTS_AUTOREACT`	Features and Toggles (Variables)
`CLAUDE_CODE_MCP_ALLOWLIST_ENV`	Plugins and MCP (Variables)
`CLAUDE_CODE_MCP_AUTO_BACKGROUND_MS`	Plugins and MCP (Variables)
`CLAUDE_CODE_TRANSCRIPT_LOCAL_GC`	Sessions and Storage (Variables)
`CLAUDE_CODE_ENABLE_TELEMETRY`	Telemetry and Debug (Variables)
`CLAUDE_CODE_SUBPROCESS_ENV_SCRUB`	Tools and Bash (Variables)
`CLAUDE_CODE_TOOL_MEMORY_LIMIT`	Tools and Bash (Variables)
`CLAUDE_CODE_ALT_SCREEN_FULL_REPAINT`	UI and Terminal (Variables)
`CLAUDE_CODE_NEW_INIT`	UI and Terminal (Variables)
`CLAUDE_CODE_NONBLOCKING_STDOUT`	UI and Terminal (Variables)
`IS_DEMO`	UI and Terminal (Variables)
`CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT`	The System Prompt (Ways to Change It)
Opus 5.5, Sonnet 5.5 by default	The System Prompt (Short or Full Prompt)
`CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT=0`	The System Prompt (Short or Full Prompt)
`CLAUDE_CODE_SIMPLE_SYSTEM_PROMPT=1`	The System Prompt (Short or Full Prompt)
Default, Sonnet 5.5	Captured System Prompts (All Variants)
Full Prompt	Captured System Prompts (All Variants)
Simple Prompt Switch on Sonnet (same text as default-sonnet)	Captured System Prompts (All Variants)
Simple Prompt Switch on Haiku (same text as default-haiku)	Captured System Prompts (All Variants)
Simple Prompt Switch on Opus (same text as default-lean)	Captured System Prompts (All Variants)
hook `type: "script"`	Probes (Effects and Differences)
`max_results`	Tools (ToolSearch)

Summary​

Settings Keys​

Environment Variables​

CLI Flags and Subcommands​

Permissions​

Hooks​

Commands​

Skills​

Subagents​

Plugins​

MCP​

Tools​

API Endpoints and Betas​

System Prompt​

Transcript and Sessions​

Headless Protocol​

Mod API​

Other​

Behaves Differently From the Docs​

Related Pages​