Changelog

June 6, 2026 · View on GitHub

0.2.93

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.167

0.2.92

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.166

0.2.91

Internal/Other Changes

  • Switched test suite from pytest-asyncio to anyio's pytest plugin, running every async test under both asyncio and trio backends to catch backend-specific regressions in CI (#1021)
  • Updated bundled Claude CLI to version 2.1.165

0.2.90

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.163

0.2.89

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.162

0.2.88

Bug Fixes

  • Trio compatibility for session stores: Ported session_store code paths (TranscriptMirrorBatcher, session_resume, sessions) from raw asyncio primitives to anyio, fixing a crash (TypeError: trio.run received unrecognized yield message) when passing session_store= to query() or ClaudeSDKClient under trio (#990)

Internal/Other Changes

  • Switched e2e CI jobs (test-e2e, test-e2e-docker, test-examples) from static API key to workload identity federation, using short-lived OIDC tokens with automatic refresh (#1018)
  • Updated bundled Claude CLI to version 2.1.161

0.2.87

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.150
  • Switched CI workflows from static API key to Workload Identity Federation for Claude authentication, using short-lived tokens instead of long-lived secrets (#984)

0.2.86

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.149

0.2.85

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.148

0.2.84

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.147

0.2.83

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.146

0.2.82

New Features

  • EffortLevel type export: Added a public EffortLevel type alias for Claude effort string levels ("low", "medium", "high", "max", "xhigh") and exported it from the package root, making it available for downstream SDK wrappers and type annotations (#951)

Bug Fixes

  • Stderr callback isolation: Fixed an issue where a user-provided stderr callback that raises an exception would silently terminate the stderr reader loop, dropping all subsequent stderr lines for the rest of the session. Exceptions are now caught per-line so a failing callback does not prevent delivery of later lines (#932)
  • CancelledError in eager-flush done callback: Fixed noisy Exception in callback log messages on shutdown when pending eager-flush tasks were cancelled. The done callback now gracefully handles CancelledError instead of unconditionally calling Task.exception() (#931)
  • Tighter permission_suggestions type: Replaced list[Any] | None with list[dict[str, Any]] | None on SDKControlPermissionRequest.permission_suggestions, enabling proper type-checking on consumers of that field (#955)

Documentation

  • Clarified that hooks dispatch for a given event is concurrent (all matchers fire in parallel), not sequential, preventing incorrect assumptions about ordering-dependent hooks like rate limiters gating subsequent hooks (#956)

Internal/Other Changes

  • Bumped mcp dependency lower bound to >=1.23.0 to address GHSA-9h52-p55h-vw2f (CVE-2025-66416), which disables DNS rebinding protection by default in older versions (#927)
  • Stabilized eager-flush transcript mirror tests with deterministic wait helpers instead of fixed asyncio.sleep(0) yields (#933)
  • Updated bundled Claude CLI to version 2.1.142

0.1.81

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.139

0.1.80

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.138

0.1.79

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.137

0.1.78

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.136

0.1.77

Bug Fixes

  • Actionable error messages after error results: Replaced the generic Command failed with exit code 1 exception raised after an error result with one carrying the result's actual error text (e.g. "Reached maximum number of turns"), matching the TypeScript SDK behavior (#918)

Documentation

  • Deprecated "Skill" in allowed_tools in favor of the skills option on ClaudeAgentOptions, which provides more granular control over available skills (#924)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.133

0.1.76

New Features

  • API error status on result messages: Added api_error_status: int | None to ResultMessage, surfacing the HTTP status code (e.g. 429, 500, 529) from failing API calls. This provides a safe-to-log field for classifying API failures when is_error=True (#923)

Bug Fixes

  • Permission suggestions deserialization: Fixed ToolPermissionContext.suggestions containing raw dicts instead of PermissionUpdate instances. Added PermissionUpdate.from_dict() so suggestions from can_use_tool callbacks can be inspected and echoed back in PermissionResultAllow(updated_permissions=...) without AttributeError (#920)

Internal/Other Changes

  • Pinned third-party GitHub Actions to immutable commit SHAs (#919)
  • Updated bundled Claude CLI to version 2.1.132

0.1.75

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.131

0.1.74

New Features

  • Hook event streaming: Added include_hook_events option to ClaudeAgentOptions. When set, hook events (PreToolUse, PostToolUse, Stop, etc.) are emitted by the CLI and yielded from the message stream as HookEventMessage, matching the TypeScript SDK's includeHookEvents (#917)
  • Defer hook decision: Added support for the "defer" hook decision in PreToolUseHookSpecificOutput.permissionDecision and new DeferredToolUse dataclass on ResultMessage.deferred_tool_use, bringing parity with the TypeScript SDK's deferred tool use round trip (#865)
  • Strict MCP config: Added strict_mcp_config option to ClaudeAgentOptions. When True, the CLI only uses MCP servers passed via mcp_servers, ignoring project, user, and global MCP configurations for fully deterministic server sets (#915)
  • Permission context enrichment: Added decision_reason, blocked_path, title, display_name, and description fields to ToolPermissionContext, enabling richer permission prompts in can_use_tool callbacks (#909)
  • updatedToolOutput for post-tool hooks: Added updatedToolOutput to PostToolUseHookSpecificOutput for replacing any tool's output before it reaches the model, not just MCP tools (#911)
  • xhigh effort level: Added "xhigh" to the effort Literal on ClaudeAgentOptions and AgentDefinition, an Opus 4.7-specific level that falls back to high on other models (#914)
  • Subprocess cleanup on parent exit: Registered an atexit handler to terminate live CLI subprocesses when the parent process exits, preventing orphaned claude processes from leaking (#916)

Bug Fixes

  • ResourceWarning on disconnect: Fixed ResourceWarning: Unclosed <MemoryObjectReceiveStream> emitted on ClaudeSDKClient disconnect and query() cleanup by closing the receive stream at the consumer boundary (#908)
  • Session created_at timestamp: Fixed list_sessions() returning created_at=None for sessions whose first JSONL record lacks a timestamp field by scanning the full head buffer instead of only the first line (#907)

Documentation

  • Clarified that can_use_tool fires only on "ask" permission decisions, not on "allow" or "deny" (#912)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.129

0.1.73

New Features

  • Eager session store flushing: Added session_store_flush option to ClaudeAgentOptions ("batched" or "eager"). When set to "eager", the transcript mirror delivers frames to SessionStore.append() in near-real-time instead of waiting for the end-of-turn flush, enabling live-tailing UIs, cross-process resume, and crash-durability use cases (#905)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.128

0.1.72

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.126

0.1.71

New Features

  • Domain allowlist fields for sandbox network config: Added allowedDomains, deniedDomains, allowManagedDomainsOnly, and allowMachLookup fields to SandboxNetworkConfig, bringing parity with the TypeScript schema and enabling Python SDK users to configure network allowlists with proper type hints (#893)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.123

0.1.70

Bug Fixes

  • In-process MCP tool results silently lost with older mcp versions: Bumped the mcp dependency floor to >=1.19.0. Older versions mishandled CallToolResult returns from SDK MCP tool handlers, causing the model to receive a validation-error blob instead of the actual tool output (#891)
  • Trio nursery corruption on early cancellation: Fixed RuntimeError: Nursery stack corrupted when breaking out of query() iteration inside a trio nursery with options.stderr set. The stderr reader now uses spawn_detached() instead of manually managing a task group, matching the approach already used for the read loop (#885)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.122

0.1.69

Documentation

  • Added docstrings to ClaudeAgentOptions fields for improved IDE autocompletion and inline documentation (#873)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.121

0.1.68

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.119

0.1.67

Bug Fixes

  • Trio compatibility restored: Fixed RuntimeError: no running event loop when using ClaudeSDKClient or query() under trio, a regression introduced in v0.1.51. Uses sniffio-based dispatch to select the correct async primitive (asyncio.Task vs trio.lowlevel.spawn_system_task) at runtime while preserving the asyncio CPU-spin and cancel-scope fixes from #746 (#870)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.120
  • Added sniffio>=1.0.0 as an explicit runtime dependency (already a transitive dep of anyio)

0.1.66

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.119

0.1.65

New Features

  • Batch session summaries: Added SessionStore.list_session_summaries() optional protocol method and fold_session_summary() helper for O(1)-per-session list views. Stores that maintain append-time summary sidecars can now serve list_sessions_from_store() without loading full transcripts, reducing round-trips from N to 1 for N sessions (#847)
  • Import local sessions to store: Added import_session_to_store() for replaying a local on-disk session into any SessionStore adapter, enabling migration from local storage to remote stores (#858)
  • Thinking display control: Added display field to ThinkingConfig types, forwarded as --thinking-display to the CLI. This lets callers override Opus 4.7's default "omitted" behavior and receive summarized thinking text (#830)
  • Server tool use and advisor result blocks: Added ServerToolUseBlock and AdvisorToolResultBlock content block types, surfacing server-executed tool calls (e.g., advisor, web_search) and their results that were previously silently dropped (#836)

Bug Fixes

  • Missing content blocks: Fixed server_tool_use and advisor_tool_result content blocks being silently dropped by the message parser, which caused messages carrying only server-side tool calls to arrive as empty AssistantMessage(content=[]) (#836)

Documentation

  • Fixed misleading permission_mode docstrings: dontAsk now correctly described as denying unapproved tools (was inverted), and auto clarified as using a model classifier (#863)

Internal/Other Changes

  • Dropped --debug-to-stderr detection from the transport layer in preparation for CLI flag removal; stderr piping now depends solely on whether a stderr callback is registered (#860)
  • Added bounded retry on session mirror append and UUID idempotency documentation (#857)
  • Updated bundled Claude CLI to version 2.1.118

0.1.64

New Features

  • SessionStore adapter: Full SessionStore support at parity with the TypeScript SDK. Includes a SessionStore protocol with 5 methods (append, load, list_sessions, delete, list_subkeys), InMemorySessionStore reference implementation, transcript mirroring via --session-mirror, session resume from store, and 9 new async store-backed helper functions (list_sessions_from_store, get_session_messages_from_store, fork_session_via_store, etc.). Also adds a 13-contract conformance test harness at claude_agent_sdk.testing.run_session_store_conformance for third-party adapter authors (#837)
  • Reference SessionStore adapters: Three copy-in reference SessionStore adapters under examples/session_stores/ — S3 (JSONL part files, mirrors the TS S3 reference), Redis (RPUSH/LRANGE lists + zset index), and Postgres (asyncpg + jsonb rows). Not shipped in the wheel; users copy the file they need into their project (#842)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.116

0.1.63

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.114

0.1.62

New Features

  • Top-level skills option: Added skills parameter to ClaudeAgentOptions for enabling skills on the main session without manually configuring allowed_tools and setting_sources. Supports "all" for every discovered skill, a list of named skills, or [] to suppress all skills (#804)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.113

0.1.61

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.112

0.1.60

New Features

  • Subagent transcript helpers: Added list_subagents() and get_subagent_messages() session helpers for reading subagent transcripts, enabling inspection of subagent message chains spawned during a session (#825)
  • Distributed tracing: Propagate W3C trace context (TRACEPARENT/TRACESTATE) to the CLI subprocess when an OpenTelemetry span is active, connecting SDK and CLI traces end-to-end. Install with pip install claude-agent-sdk[otel] for optional OpenTelemetry support (#821)
  • Cascading session deletion: delete_session() now removes the sibling subagent transcript directory alongside the session file, matching TypeScript SDK behavior (#805)

Bug Fixes

  • Empty setting sources: Fixed setting_sources=[] being silently dropped (treated as falsy), which caused the CLI to load default settings instead of disabling all filesystem settings. An empty list now correctly passes --setting-sources= to disable all sources (#822)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.111

0.1.59

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.105

0.1.58

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.97

0.1.57

New Features

  • Cross-user prompt caching: Added exclude_dynamic_sections option to SystemPromptPreset, enabling cross-user prompt cache hits by moving per-user dynamic sections (working directory, memory, git status) out of the system prompt (#797)
  • Auto permission mode: Added "auto" to the PermissionMode type, bringing parity with the TypeScript SDK and CLI v2.1.90+ (#785)

Bug Fixes

  • Thinking configuration: Fixed thinking={"type": "adaptive"} incorrectly mapping to --max-thinking-tokens 32000 instead of --thinking adaptive. The disabled type similarly now uses --thinking disabled instead of --max-thinking-tokens 0, matching the TypeScript SDK behavior (#796)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.96

0.1.56

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.92

0.1.55

Bug Fixes

  • MCP large tool results: Forward maxResultSizeChars from ToolAnnotations via _meta to bypass Zod annotation stripping in the CLI, fixing silent truncation of large MCP tool results (>50K chars) (#756)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.91

0.1.53

Bug Fixes

  • Setting sources flag: Fixed --setting-sources being passed as an empty string when not provided, which caused the CLI to misparse subsequent flags (#778)
  • String prompt deadlock: Fixed deadlock when using query() with a string prompt and hooks/MCP servers that trigger many tool calls, by spawning wait_for_result_and_end_input() as a background task (#780)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.88

0.1.52

New Features

  • Context usage: Added get_context_usage() method to ClaudeSDKClient for querying context window usage by category (#764)
  • Annotated parameter descriptions: The @tool decorator and create_sdk_mcp_server now support typing.Annotated for per-parameter descriptions in JSON Schema (#762)
  • ToolPermissionContext fields: Exposed tool_use_id and agent_id in ToolPermissionContext for distinguishing parallel permission requests (#754)
  • Session ID option: Added session_id option to ClaudeAgentOptions for specifying custom session IDs (#750)

Bug Fixes

  • String prompt in connect(): Fixed connect(prompt="...") silently dropping the string prompt, causing receive_messages() to hang indefinitely (#769)
  • Cancel request handling: Implemented control_cancel_request handling so in-flight hook callbacks are properly cancelled when the CLI abandons them (#751)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.87
  • Increased CI timeout for example tests and reduced sleep duration in error handling example (#760)

0.1.51

New Features

  • Session management: Added fork_session(), delete_session(), and offset-based pagination for session listing (#744)
  • Task budget: Added task_budget option for token budget management (#747)
  • SystemPromptFile: Added support for --system-prompt-file CLI flag via SystemPromptFile (#591)
  • AgentDefinition fields: Added disallowedTools, maxTurns, and initialPrompt to AgentDefinition (#759)
  • Preserved fields: Preserve dropped fields on AssistantMessage and ResultMessage for forward compatibility (#718)

Bug Fixes

  • Python 3.10 compatibility: Use typing_extensions.TypedDict on Python 3.10 for NotRequired support (#761)
  • ResultMessage errors field: Added missing errors field to ResultMessage (#749)
  • Async generator cleanup: Resolved cross-task cancel scope RuntimeError on async generator cleanup (#746)
  • MCP tool input_schema: Convert TypedDict input_schema to proper JSON Schema in SDK MCP tools (#736)
  • initialize_timeout: Pass initialize_timeout from env var in query() (#743)
  • Async event loop blocking: Defer CLI discovery to connect() to avoid blocking async event loops (#722)
  • Permission mode: Added missing dontAsk permission mode to types (#719)
  • Environment filtering: Filter CLAUDECODE env var from subprocess environment (#732)
  • Process cleanup: Added SIGKILL fallback when SIGTERM handler blocks in close() (#729)
  • Duplicate warning: Removed duplicate version warning and included CLI path (#720)
  • MCP resource types: Handle resource_link and embedded resource content types in SDK MCP tools (#725)
  • Stdin timeout: Removed stdin timeout for hooks and SDK MCP servers (#731)
  • Stdout parsing: Skip non-JSON lines on CLI stdout to prevent buffer corruption (#723)
  • MCP error propagation: Propagate is_error flag from SDK MCP tool results (#717)
  • Install script: Retry install.sh fetch on 429 with pipefail + jitter (#708)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.85

0.1.50

New Features

  • Session info: Added tag and created_at fields to SDKSessionInfo and new get_session_info() function for retrieving session metadata (#667)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.81
  • Hardened PyPI publish workflow against partial-upload failures (#700)
  • Added daily PyPI storage quota monitoring (#705)

0.1.49

New Features

  • AgentDefinition: Added skills, memory, and mcpServers fields (#684)
  • AssistantMessage usage: Preserve per-turn usage on AssistantMessage (#685)
  • Session tagging: Added tag_session() with Unicode sanitization (#670)
  • Session renaming: Added rename_session() (#668)
  • RateLimitEvent: Added typed RateLimitEvent message (#648)

Bug Fixes

  • CLAUDE_CODE_ENTRYPOINT: Use default-if-absent semantics to match TS SDK (#686)
  • Fine-grained tool streaming: Reverted the env-var workaround from 0.1.48; partial-message delivery is now handled upstream (#671)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.77
  • Added macOS x86_64 wheel to the published matrix (#661)
  • Upload wheel-check artifacts in CI (#662)
  • Docs: clarified allowed_tools as a permission allowlist (#649)

0.1.48

Bug Fixes

  • Fine-grained tool streaming: Fixed include_partial_messages=True not delivering input_json_delta events by enabling the CLAUDE_CODE_ENABLE_FINE_GRAINED_TOOL_STREAMING environment variable in the subprocess. This regression affected versions 0.1.36 through 0.1.47 for users without the server-side feature flag (#644)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.71

0.1.47

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.70

0.1.46

New Features

  • Session history functions: Added list_sessions() and get_session_messages() top-level functions for retrieving past session data (#622)
  • MCP control methods: Added add_mcp_server(), remove_mcp_server(), and typed McpServerStatus for runtime MCP server management (#620)
  • Typed task messages: Added TaskStarted, TaskProgress, and TaskNotification message subclasses for better type safety when handling task-related events (#621)
  • ResultMessage stop_reason: Added stop_reason field to ResultMessage for inspecting why a conversation turn ended (#619)
  • Hook input enhancements: Added agent_id and agent_type fields to tool-lifecycle hook inputs (PreToolUseHookInput, PostToolUseHookInput, PostToolUseFailureHookInput) (#628)

Bug Fixes

  • String prompt MCP initialization: Fixed an issue where passing a string prompt would close stdin before MCP server initialization completed, causing MCP servers to fail to register (#630)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.69

0.1.45

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.63

0.1.44

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.59

0.1.43

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.56

0.1.42

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.55

0.1.41

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.52

0.1.40

Bug Fixes

  • Unknown message type handling: Fixed an issue where unrecognized CLI message types (e.g., rate_limit_event) would crash the session by raising MessageParseError. Unknown message types are now silently skipped, making the SDK forward-compatible with future CLI message types (#598)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.51

0.1.39

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.49

0.1.38

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.47

0.1.37

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.44

0.1.36

New Features

  • Thinking configuration: Added ThinkingConfig types (ThinkingConfigAdaptive, ThinkingConfigEnabled, ThinkingConfigDisabled) and thinking field to ClaudeAgentOptions for fine-grained control over extended thinking behavior. The new thinking field takes precedence over the now-deprecated max_thinking_tokens field (#565)
  • Effort option: Added effort field to ClaudeAgentOptions supporting "low", "medium", "high", and "max" values for controlling thinking depth (#565)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.42

0.1.35

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.39

0.1.34

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.38
  • Updated CI workflows to use Claude Opus 4.6 model (#556)

0.1.33

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.37

0.1.32

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.36

0.1.31

New Features

  • MCP tool annotations support: Added support for MCP tool annotations via the @tool decorator's new annotations parameter, allowing developers to specify metadata hints like readOnlyHint, destructiveHint, idempotentHint, and openWorldHint. Re-exported ToolAnnotations from claude_agent_sdk for convenience (#551)

Bug Fixes

  • Large agent definitions: Fixed an issue where large agent definitions would silently fail to register due to platform-specific CLI argument size limits (ARG_MAX). Agent definitions are now sent via the initialize control request through stdin, matching the TypeScript SDK approach and allowing arbitrarily large agent payloads (#468)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.33

0.1.30

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.32

0.1.29

New Features

  • New hook events: Added support for three new hook event types (#545):

    • Notification — for handling notification events with NotificationHookInput and NotificationHookSpecificOutput
    • SubagentStart — for handling subagent startup with SubagentStartHookInput and SubagentStartHookSpecificOutput
    • PermissionRequest — for handling permission requests with PermissionRequestHookInput and PermissionRequestHookSpecificOutput

  • Enhanced hook input/output types: Added missing fields to existing hook types (#545):

    • PreToolUseHookInput: added tool_use_id
    • PostToolUseHookInput: added tool_use_id
    • SubagentStopHookInput: added agent_id, agent_transcript_path, agent_type
    • PreToolUseHookSpecificOutput: added additionalContext
    • PostToolUseHookSpecificOutput: added updatedMCPToolOutput

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.31

0.1.28

Bug Fixes

  • AssistantMessage error field: Fixed AssistantMessage.error field not being populated due to incorrect data path. The error field is now correctly read from the top level of the response (#506)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.30

0.1.27

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.29

0.1.26

New Features

  • PostToolUseFailure hook event: Added PostToolUseFailure hook event type for handling tool use failures, including PostToolUseFailureHookInput and PostToolUseFailureHookSpecificOutput types (#535)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.27

0.1.25

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.23

0.1.24

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.22

0.1.23

Features

  • MCP status querying: Added public get_mcp_status() method to ClaudeSDKClient for querying MCP server connection status without accessing private internals (#516)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.20

0.1.22

Features

  • Added tool_use_result field to UserMessage (#495)

Bug Fixes

  • Added permissions to release job in auto-release workflow (#504)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.19
  • Extracted build-and-publish workflow into reusable component (#488)

0.1.21

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.15

0.1.20

Bug Fixes

  • Permission callback test reliability: Improved robustness of permission callback end-to-end tests (#485)

Documentation

  • Updated Claude Agent SDK documentation link (#442)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.9
  • CI improvements: Updated claude-code actions from @beta to @v1 (#467)

0.1.19

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.1.1
  • CI improvements: Jobs requiring secrets now skip when running from forks (#451)
  • Fixed YAML syntax error in create-release-tag workflow (#429)

0.1.18

Internal/Other Changes

  • Docker-based test infrastructure: Added Docker support for running e2e tests in containerized environments, helping catch Docker-specific issues (#424)
  • Updated bundled Claude CLI to version 2.0.72

0.1.17

New Features

  • UserMessage UUID field: Added uuid field to UserMessage response type, making it easier to use the rewind_files() method by providing direct access to message identifiers needed for file checkpointing (#418)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.0.70

0.1.16

Bug Fixes

  • Rate limit detection: Fixed parsing of the error field in AssistantMessage, enabling applications to detect and handle API errors like rate limits. Previously, the error field was defined but never populated from CLI responses (#405)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.0.68

0.1.15

New Features

  • File checkpointing and rewind: Added enable_file_checkpointing option to ClaudeAgentOptions and rewind_files(user_message_id) method to ClaudeSDKClient and Query. This enables reverting file changes made during a session back to a specific checkpoint, useful for exploring different approaches or recovering from unwanted modifications (#395)

Documentation

  • Added license and terms section to README (#399)

0.1.14

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.0.62

0.1.13

Bug Fixes

  • Faster error handling: CLI errors (e.g., invalid session ID) now propagate to pending requests immediately instead of waiting for the 60-second timeout (#388)
  • Pydantic 2.12+ compatibility: Fixed PydanticUserError caused by McpServer type only being imported under TYPE_CHECKING (#385)
  • Concurrent subagent writes: Added write lock to prevent BusyResourceError when multiple subagents invoke MCP tools in parallel (#391)

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.0.59

0.1.12

New Features

  • Tools option: Added tools option to ClaudeAgentOptions for controlling the base set of available tools, matching the TypeScript SDK functionality. Supports three modes:
    • Array of tool names to specify which tools should be available (e.g., ["Read", "Edit", "Bash"])
    • Empty array [] to disable all built-in tools
    • Preset object {"type": "preset", "preset": "claude_code"} to use the default Claude Code toolset
  • SDK beta support: Added betas option to ClaudeAgentOptions for enabling Anthropic API beta features. Currently supports "context-1m-2025-08-07" for extended context window

0.1.11

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.0.57

0.1.10

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.0.53

0.1.9

Internal/Other Changes

  • Updated bundled Claude CLI to version 2.0.49

0.1.8

Features

  • Claude Code is now included by default in the package, removing the requirement to install it separately. If you do wish to use a separately installed build, use the cli_path field in Options.

0.1.7

Features

  • Structured outputs support: Agents can now return validated JSON matching your schema. See https://docs.claude.com/en/docs/agent-sdk/structured-outputs. (#340)
  • Fallback model handling: Added automatic fallback model handling for improved reliability and parity with the TypeScript SDK. When the primary model is unavailable, the SDK will automatically use a fallback model (#317)
  • Local Claude CLI support: Added support for using a locally installed Claude CLI from ~/.claude/local/claude, enabling development and testing with custom Claude CLI builds (#302)

0.1.6

Features

  • Max budget control: Added max_budget_usd option to set a maximum spending limit in USD for SDK sessions. When the budget is exceeded, the session will automatically terminate, helping prevent unexpected costs (#293)
  • Extended thinking configuration: Added max_thinking_tokens option to control the maximum number of tokens allocated for Claude's internal reasoning process. This allows fine-tuning of the balance between response quality and token usage (#298)

Bug Fixes

  • System prompt defaults: Fixed issue where a default system prompt was being used when none was specified. The SDK now correctly uses an empty system prompt by default, giving users full control over agent behavior (#290)

0.1.5

Features

  • Plugin support: Added the ability to load Claude Code plugins programmatically through the SDK. Plugins can be specified using the new plugins field in ClaudeAgentOptions with a SdkPluginConfig type that supports loading local plugins by path. This enables SDK applications to extend functionality with custom commands and capabilities defined in plugin directories

0.1.4

Features

  • Skip version check: Added CLAUDE_AGENT_SDK_SKIP_VERSION_CHECK environment variable to allow users to disable the Claude Code version check. Set this environment variable to skip the minimum version validation when the SDK connects to Claude Code. (Only recommended if you already have Claude Code 2.0.0 or higher installed, otherwise some functionality may break)
  • SDK MCP server tool calls can now return image content blocks

0.1.3

Features

  • Strongly-typed hook inputs: Added typed hook input structures (PreToolUseHookInput, PostToolUseHookInput, UserPromptSubmitHookInput, etc.) using TypedDict for better IDE autocomplete and type safety. Hook callbacks now receive fully typed input parameters

Bug Fixes

  • Hook output field conversion: Fixed bug where Python-safe field names (async_, continue_) in hook outputs were not being converted to CLI format (async, continue). This caused hook control fields to be silently ignored, preventing proper hook behavior. The SDK now automatically converts field names when communicating with the CLI

Internal/Other Changes

  • CI/CD: Re-enabled Windows testing in the end-to-end test workflow. Windows CI had been temporarily disabled but is now fully operational across all test suites

0.1.2

Bug Fixes

  • Hook output fields: Added missing hook output fields to match the TypeScript SDK, including reason, continue_, suppressOutput, and stopReason. The decision field now properly supports both "approve" and "block" values. Added AsyncHookJSONOutput type for deferred hook execution and proper typing for hookSpecificOutput with discriminated unions

0.1.1

Features

  • Minimum Claude Code version check: Added version validation to ensure Claude Code 2.0.0+ is installed. The SDK will display a warning if an older version is detected, helping prevent compatibility issues
  • Updated PermissionResult types: Aligned permission result types with the latest control protocol for better type safety and compatibility

Improvements

  • Model references: Updated all examples and tests to use the simplified claude-sonnet-4-5 model identifier instead of dated version strings

0.1.0

Introducing the Claude Agent SDK! The Claude Code SDK has been renamed to better reflect its capabilities for building AI agents across all domains, not just coding.

Breaking Changes

Type Name Changes

  • ClaudeCodeOptions renamed to ClaudeAgentOptions: The options type has been renamed to match the new SDK branding. Update all imports and type references:

    # Before
from claude_agent_sdk import query, ClaudeCodeOptions
options = ClaudeCodeOptions(...)

# After
from claude_agent_sdk import query, ClaudeAgentOptions
options = ClaudeAgentOptions(...)

System Prompt Changes

  • Merged prompt options: The custom_system_prompt and append_system_prompt fields have been merged into a single system_prompt field for simpler configuration
  • No default system prompt: The Claude Code system prompt is no longer included by default, giving you full control over agent behavior. To use the Claude Code system prompt, explicitly set: 
    system_prompt={"type": "preset", "preset": "claude_code"}

Settings Isolation

  • No filesystem settings by default: Settings files (settings.json, CLAUDE.md), slash commands, and subagents are no longer loaded automatically. This ensures SDK applications have predictable behavior independent of local filesystem configurations
  • Explicit settings control: Use the new setting_sources field to specify which settings locations to load: ["user", "project", "local"]

For full migration instructions, see our migration guide.

New Features

  • Programmatic subagents: Subagents can now be defined inline in code using the agents option, enabling dynamic agent creation without filesystem dependencies. Learn more
  • Session forking: Resume sessions with the new fork_session option to branch conversations and explore different approaches from the same starting point. Learn more
  • Granular settings control: The setting_sources option gives you fine-grained control over which filesystem settings to load, improving isolation for CI/CD, testing, and production deployments

Documentation

0.0.22

  • Introduce custom tools, implemented as in-process MCP servers.
  • Introduce hooks.
  • Update internal Transport class to lower-level interface.
  • ClaudeSDKClient can no longer be run in different async contexts.

0.0.19

  • Add ClaudeCodeOptions.add_dirs for --add-dir
  • Fix ClaudeCodeSDK hanging when MCP servers log to Claude Code stderr

0.0.18

  • Add ClaudeCodeOptions.settings for --settings

0.0.17

  • Remove dependency on asyncio for Trio compatibility

0.0.16

  • Introduce ClaudeSDKClient for bidirectional streaming conversation
  • Support Message input, not just string prompts, in query()
  • Raise explicit error if the cwd does not exist

0.0.14

  • Add safety limits to Claude Code CLI stderr reading
  • Improve handling of output JSON messages split across multiple stream reads

0.0.13

  • Update MCP (Model Context Protocol) types to align with Claude Code expectations
  • Fix multi-line buffering issue
  • Rename cost_usd to total_cost_usd in API responses
  • Fix optional cost fields handling