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Changelog

Claude Agent SDK

Anthropic Agent SDK, showing TypeScript releases
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Latest Version:v0.3.319
Loaded Releases:95
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Latest Releases (95)

v0.3.319New

v0.3.319

November 6, 2026

  • •Added MCP task support in SDK sessions (not on Bedrock, Vertex or Foundry): with CLAUDE_AUTO_BACKGROUND_TASKS=1 and streaming input, an MCP task runs in the background with task_type "mcp_task"
  • •Fixed the OpenTelemetry claude_code.session.count metric counting prewarm() processes that were never claimed; a pre-started process now counts once, when SpareProcess.claim() succeeds
  • •Fixed session_writes_lost listing the wrong session in transcript_session_ids after /clear in a session resumed from a transcript file outside the projects folder
  • •Improved deleteSession() to reject with ENOTEMPTY if the session's folder could not be fully deleted
  • •Changed session_writes_lost to be sent only when the CLI exits 0; a run that ends on an error result now gets only the stderr line
  • •Updated to parity with Claude Code v2.1.319
v0.3.318New

v0.3.318

November 4, 2026

  • •Added an optional credential_expires_at field to result messages: when the stored claude.ai sign-in in use ends
  • •Added the config_file_invalid startup failure reason, reported when a configuration file read at startup isn't valid JSON
  • •Fixed the interrupt response missing a message held behind a model change: it is now listed, cancelled with cancel_queued, and stopped at start-up as a queued message is
  • •Changed agentProgressSummaries: while the subagent waits for a response on a likely-cold prompt cache, a summary can wait up to 5 minutes, and is not sent if the subagent ends first
  • •Changed status in PushNotificationInput to optional
  • •Updated to parity with Claude Code v2.1.318
v0.3.317New

v0.3.317

November 3, 2026

  • •Added onFailure to hook matchers: with "block", a hook that throws or returns invalid output blocks the action
  • •Added a warning message in the stream when a hook callback fails
  • •Added a session_writes_lost system message, sent after the last result when a full disk or disk quota kept the CLI from saving the session transcript or ~/.claude.json
  • •Added initialize_not_first to startup_failure_reason, for a --await-initialize launch whose first stdin line is not the initialize request
  • •Added task.description to the TaskCreate tool's tool_use_result: the description the task was created with
  • •Added lossy to readFile() utf-8 answers: true when decoding replaced bytes that are not valid UTF-8
  • •Removed the file_unchanged variant of FileReadOutput in sdk-tools.d.ts; a repeated Read now returns the file content
  • •Fixed setMcpServers closing a folder's .mcp.json and local-scope MCP servers in sessions started with prewarm() and bound with SpareProcess.claim()
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  • •Updated to parity with Claude Code v2.1.317
v0.3.316

v0.3.316

October 31, 2026

  • •Added permissions.blockReadsExemptPaths to the Settings type: paths, read only from --settings and settings the host sends, that blockReadsOutsideWorkingDirectories lets through without making them working directories
  • •Updated to parity with Claude Code v2.1.316
v0.3.314

v0.3.314

October 30, 2026

  • •Added sandbox_required_unavailable to startup_failure_reason, for the result Claude Code writes when a required sandbox cannot run
  • •Added permissions.blockWritesOutsideWorkingDirectories to the Settings type
  • •Added prewarm() (alpha) to the @anthropic-ai/claude-agent-sdk/core entry point
  • •Fixed a settings file left out of settingSources still supplying some settings, such as auto mode rules and saved permission consents
  • •Updated to parity with Claude Code v2.1.314
v0.3.312

v0.3.312

October 27, 2026

  • •Added autoMode, skipAutoPermissionPrompt, useAutoModeDuringPlan and permissions.disableAutoMode to the Settings type
  • •Added unanswered (skipped, replied_in_chat or dismissed) to AskUserQuestion answers' per-question annotations; send it only when system/init lists the ask_user_question_unanswered_v1 capability
  • •Fixed resolveSettings() returning mistyped managed auto-mode settings, such as permissions.disableAutoMode: true, as written instead of reading them as the CLI does; a user or project settings file whose auto-mode keys hold an invalid value is now skipped, as in the CLI
  • •Updated to parity with Claude Code v2.1.312
v0.3.311

v0.3.311

October 26, 2026

  • •Added cacheCreationEphemeral5mInputTokens and cacheCreationEphemeral1hInputTokens to ModelUsage, splitting cacheCreationInputTokens by cache lifetime
  • •Changed background start-up work to wait until the first model request is sent, for about 10 seconds at most, when the first message arrives during start-up
  • •Changed the minimum supported Node.js version from 18.0.0 to 18.14.0
  • •Updated to parity with Claude Code v2.1.311
v0.3.310

v0.3.310

October 24, 2026

  • •Updated to parity with Claude Code v2.1.310
v0.3.309

v0.3.309

October 23, 2026

  • •Fixed host-supplied managedSettings dropping disableAllHooks, disableSkillShellExecution and empty allowedHttpHookUrls / httpHookAllowedEnvVars lists
  • •Changed extractFromBunfs() to extract the embedded CLI into its own per-user temp directory (claude-agent-sdk-<uid>, or claude-agent-sdk on Windows) instead of Claude Code's temp root
  • •Changed extractFromBunfs() to reuse an already-extracted file only when its bytes match the embedded binary, replacing it otherwise
  • •Updated to parity with Claude Code v2.1.309
v0.3.308

v0.3.308

October 22, 2026

  • •Updated to parity with Claude Code v2.1.308
v0.3.307

v0.3.307

October 22, 2026

  • •Added wakeup_source to the command_lifecycle started frame of a scheduled wakeup or task, and scheduled_for for a wakeup (capability lifecycle_wakeup_source_v1), so a host can tell which one fired
  • •Added supportedDialogKinds to browser SDK query(), sent on initialize; a non-empty list requires onUserDialog
  • •Updated to parity with Claude Code v2.1.307
v0.3.306

v0.3.306

October 21, 2026

  • •Updated to parity with Claude Code v2.1.306
v0.3.305

v0.3.305

October 20, 2026

  • •Added recommendations and fix to the get_usage response's behavior windows
  • •Fixed servers set with setMcpServers being replaced later in the session by a same-named server from the user's own settings
  • •Fixed startup() with initializeTimeoutMs: null counting time spent in SessionStart or Setup hooks against its 60-second limit; null now works like leaving the option out
  • •Changed the startup() and prewarm() timeout error for a start with no open SessionStart or Setup hook: it lists possible causes and no longer says to check authentication and network
  • •Updated to parity with Claude Code v2.1.305
v0.3.304

v0.3.304

October 19, 2026

  • •Added suspendSseStream(query) and resumeSseStream(query) to the browser SDK: close a query's event stream and reopen it later without ending the query
  • •Added stable row ids to getContextUsage(), and, when the CLI answers on its own stdio, plugin ids, agent and skill file paths, and per-server MCP instruction token shares
  • •Fixed startup() timing out while a SessionStart or Setup command hook was running when no initializeTimeoutMs is passed: up to 10 minutes of that time no longer counts toward the 60-second limit, and the timeout error now says what the process reported
  • •Fixed startup() keeping every hook_progress message of a running SessionStart or Setup hook in memory until it resolved; it now keeps only the newest one for each hook
  • •Updated to parity with Claude Code v2.1.304
v0.3.303

v0.3.303

October 19, 2026

  • •Updated to parity with Claude Code v2.1.303
v0.3.302

v0.3.302

October 16, 2026

  • •Fixed structured output results delivering a response's output as structured_output when the API refused that response; the result is now an error with no payload
  • •Changed an omitted permissionMode to start in default mode on third-party providers, with telemetry off or on a fresh install; pass permissionMode: 'auto' to keep auto mode
  • •Changed fork subagents (subagent_type: "fork") to be on by default in SDK sessions, as in the terminal; run_in_background is still offered, and CLAUDE_CODE_FORK_SUBAGENT=0 turns them off
  • •Updated to parity with Claude Code v2.1.302
v0.3.301

v0.3.301

October 15, 2026

  • •Added per-tool permission policies to sdk-type MCP server configs: tools entries with permission_policy always_ask or always_deny, applied on initialize and setMcpServers()
  • •Added BUILTIN_TOOL_NAMES and LEGACY_TOOL_NAME_ALIASES exports: the public built-in tool names and their earlier names, for checking permission rules and tool settings
  • •Added addPlugins to Query.reloadPlugins() so a host can load more plugin folders into a running session
  • •Fixed setModel() with a model ID failing while the account is at its five-hour or weekly usage limit; the model now applies and the next message reports the limit
  • •Changed the error when a full disk keeps the login from being refreshed: error is now invalid_request, not authentication_failed, and api_error_status is null, not 401
  • •Changed mcpServerStatus() to still report a tool's _meta.ui.visibility when the rest of its _meta.ui fails validation
  • •Updated to parity with Claude Code v2.1.301
v0.3.300

v0.3.300

October 14, 2026

  • •Fixed importSessionToStore skipping transcript rows that contain a Unicode line or paragraph separator (U+2028, U+2029) on Node 24 and Bun
  • •Fixed a background subagent's final report in auto mode being joined into one turn with another message from the same subagent; the report now always runs as its own turn
  • •Fixed rewind_conversation with interrupt_if_running stopping the running turn before refusing with "unseen later turn"
  • •Reverted canUseTool options carrying suppressAlwaysAllowRule: true for connector tools that an organization set to require approval (added in 0.3.292)
  • •Improved the browser SDK bundle (@anthropic-ai/claude-agent-sdk/browser): 40% smaller to download, by no longer bundling a Node crypto polyfill
  • •Changed thinking: { type: 'disabled' } and maxThinkingTokens: 0 to run as adaptive thinking on models that can't turn thinking off
  • •Changed updatedInput from PreToolUse and PermissionRequest hook callbacks: it is now validated like Claude's own input and unknown keys are dropped; canUseTool is unchanged
  • •Updated to parity with Claude Code v2.1.300
v0.3.299

v0.3.299

October 14, 2026

  • •Added an optional nextFireAt (epoch ms of the next run) to the CronCreate and CronList tool outputs
  • •Added property_order to the elicitation control request: a form's field names in the order the MCP server listed them, for hosts whose transport keeps no JSON object key order
  • •Fixed rewind_conversation answering "target not found" for a message stopped during its prompt hooks or plugins: until a reply or input follows, it answers rewound: true with a null prefillText
  • •Fixed in-process SDK MCP servers named constructor or toString being silently dropped when a prewarm() process is claimed with SpareProcess.claim()
  • •Fixed queued user messages with content-block arrays running together without a line break when merged into one turn
  • •Fixed origin.body on a user message that merges several queued peer messages (from other sessions or agents) carrying only the first message's text; it is now omitted
  • •Changed initialize, mcp_set_servers and claim_session to refuse the reserved MCP server names __proto__, __defineGetter__, __defineSetter__, __lookupGetter__, __lookupSetter__
  • •Updated to parity with Claude Code v2.1.299
v0.3.296

v0.3.296

October 9, 2026

  • •Added claude_code_version to the initialize control response so clients know the CLI version before the first turn
  • •Added autoCompactWindow to AgentDefinition, so a subagent can auto-compact earlier than the main conversation's window
  • •Fixed the sandbox option discarding an inline settings.sandbox block: the two now merge, the option's values win, and deny and credential lists from both sides are combined
  • •Changed the default limit on MCP tool descriptions sent up front and on MCP server instructions, in-process SDK servers included, from 2,048 to 4,096 characters
  • •Changed permission answers that arrive after a restart to be parsed like live ones: over 4,096 updatedPermissions entries count as a denial, and a malformed list is ignored as a whole
  • •Updated to parity with Claude Code v2.1.296
v0.3.295

v0.3.295

October 8, 2026

  • •Added overageEnabled to SDKRateLimitInfo: on usage-limit warnings, whether the account has extra usage turned on
  • •Fixed an MCP server added with mcp_set_servers sometimes keeping an outdated tool list when another server in the same request connected later
  • •Fixed assistant text blocks losing their citations in streamed responses
  • •Fixed Claude being told "disabled by the user" about an in-process MCP server that was switched off with toggleMcpServer()
  • •Fixed rate_limit_event with status allowed_warning omitting overageStatus, overageResetsAt and overageDisabledReason, which allowed and rejected events already carry
  • •Changed MCP tool descriptions the model loads through tool search, including those from in-process SDK servers, to be cut at 16,384 characters instead of 2,048
  • •Changed a permission answer whose updatedPermissions holds over 4,096 updates, rules and directories to count as a denial
  • •Changed tool_result_meta[].non_execution_kind to be absent when a mod withheld the result of a tool that ran without error; it was permission-rule
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  • •Changed pasted_content on user messages to be ignored when it holds over 1,000 entries and blocks in all
  • •Changed how the SDK passes option values to Claude Code: the values of its named options are now sent in the same argument as their flag (--flag=value)
  • •Changed tool_use_result for MCP Apps tools: structuredContent or _meta over 8,388,608 JSON characters is left off, and _meta.ui with no ui:// resource no longer lifts the ordinary caps
  • •Changed tool_use_result for MCP tools: when a long result is saved to a file, or cut because it could not be, the text kept past 500,000 characters is dropped, with a note of how much
  • •Changed tool_use_result for MCP tools: a result _meta over 1,048,576 JSON characters is left off, except for SDK-server tools; so is text blocks' _meta that totals over 65,536
  • •Updated to parity with Claude Code v2.1.295
v0.3.294

v0.3.294

October 8, 2026

  • •Updated to parity with Claude Code v2.1.294
v0.3.293

v0.3.293

October 7, 2026

  • •Added an optional subagent_type to background_tasks_changed task entries, so hosts can name each subagent's type without pairing with task_started
  • •Updated to parity with Claude Code v2.1.293
v0.3.292

v0.3.292

October 6, 2026

  • •Added agent_id to the assistant and user messages a subagent produces; it equals the task_id on that subagent's task events and stays the same when the subagent is resumed
  • •Added parent_task_id to task_started events and background_tasks_changed entries, naming the subagent task that launched a task
  • •Added run_id to background task events and origin.runId to task notifications, so a host can tell a resumed task's runs apart
  • •Added typed sections and notes to the ListAgents tool's tool_use_result, so hosts can list agents without parsing its text
  • •Added recipient_kind to SendMessage tool_use inputs on assistant messages, and their top-level approve is now always a boolean, so hosts no longer infer them from the raw input
  • •Added two optional fields to the ReadNotifications tool output: read_at, when the tool read the session's queued notifications, and arrived_at on each notification, when it reached the session
  • •Fixed subagents with a declared auto permission mode having their tool calls decided by the auto-mode classifier instead of the canUseTool callback when auto mode is unavailable
  • •Changed background_tasks_changed for a finishing background task to arrive after that task's task_updated and task_notification
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  • •Changed canUseTool options to carry suppressAlwaysAllowRule: true for connector tools that an organization set to require approval, so hosts can hide their "always allow" choice
  • •Updated to parity with Claude Code v2.1.292
v0.3.291

v0.3.291

October 6, 2026

  • •Updated to parity with Claude Code v2.1.291
v0.3.290

v0.3.290

October 6, 2026

  • •Added an optional offset field to the WebFetch tool input for reading on through long pages
  • •Fixed failed Claude in Chrome tool calls dropping the result's _meta: when the result has one, tool_use_result is now { content, _meta }, as for other MCP tools
  • •Fixed deny and ask rules missing toolAliases tools when written with a wildcard (Bash*), a match-all pattern (Bash(**), also on the mapped name), or an input field also in disallowedTools
  • •Fixed a user message sent again under the same uuid being replayed (--replay-user-messages) while the first copy still waited for its turn; its replay now comes when a turn takes it
  • •Fixed includePartialMessages streams leaving a message without message_stop when the stream was cut, interrupted or fell back to non-streaming
  • •Changed user_message_uuid, user_message_uuids and resume_reason to also be set on a turn a restarted worker resumes from a permission answer or from tool calls still in flight
  • •Updated to parity with Claude Code v2.1.290
v0.3.289

v0.3.289

October 4, 2026

  • •Updated to parity with Claude Code v2.1.289
v0.3.288

v0.3.288

October 2, 2026

  • •Updated to parity with Claude Code v2.1.288
v0.3.287

v0.3.287

October 1, 2026

  • •Added optional remote-session latency fields (first_text_post_queue_wait_ms, first_text_post_queued_behind) to the success result message
  • •Fixed includePartialMessages streams sending a cut-short reply's message_stop late or never, so apps could show the reply as still in progress
  • •Fixed the error for a revoked claude.ai login, which now reads "Failed to authenticate: OAuth token revoked" instead of a generic or "does not have access" message
  • •Fixed a tool call to an in-process MCP server being left waiting after toggleMcpServer() disabled the server or setMcpServers() removed it
  • •Fixed commands_changed arriving before init, or twice, at session start: the initialize response now includes commands registered at startup
  • •Changed tool_use_result for a WebFetch or WebSearch call that steps aside for a priority "now" message to { detachedToolCall: true }; the result follows in a later turn
  • •Changed tool_use_result for MCP tools: structuredContent over 1,048,576 JSON characters is left off and structuredContentOmitted: true set, except for SDK-server and MCP Apps tools
  • •Updated to parity with Claude Code v2.1.287
v0.3.286

v0.3.286

September 30, 2026

  • •Added the initialize response field sdk_mcp_manifests_parked and the system/init capabilities sdk_mcp_manifests and sdk_mcp_tools_list_changed
  • •Fixed foreground subagents sometimes not receiving the task-tracking tools listed in tools or allowedTools
  • •Fixed an SDK MCP server listing no tools when one tool's schema cannot be converted to JSON Schema; that tool is now left out with a warning naming it
  • •Fixed toggleMcpServer() not disconnecting, and failing to re-enable, an in-process MCP server created with createSdkMcpServer(), except one named claude-in-chrome
  • •Changed a person's priority now message to move running shell commands, agents and MCP calls to the background and join the running turn instead of stopping it
  • •Changed the TypeScript Agent SDK to leave an omitted permissionMode to Claude Code, so a settings defaultMode now applies and, on third-party providers or with telemetry off, the session starts in auto mode like claude -p; pass permissionMode: 'default' for manual approvals
  • •Updated to parity with Claude Code v2.1.286
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