github.com/anthropics/anthropic-sdk-go

1.66.0 (2026-08-19)

Full Changelog: v1.65.0...v1.66.0

Features

• api: managed agents web search config and self hosted sandbox memory (694b03a)

Full Changelog: v1.65.0...v1.66.0

Features

• api: managed agents web search config and self hosted sandbox memory (694b03a)

1.65.0 (2026-08-19)

Full Changelog: v1.64.0...v1.65.0

Features

• api: Files and Skills APIs are now GA; add computer use and browser use toolsets (e7be7af)

Full Changelog: v1.64.0...v1.65.0

Features

• api: Files and Skills APIs are now GA; add computer use and browser use toolsets (e7be7af)

1.64.0 (2026-08-18)

Full Changelog: v1.63.1...v1.64.0

Features

• api: additions to files and memory stores (5c105da)
• api: updates to skill, files, and user profiles (a0061d6)

Bug Fixes

• api: remove unsupported mid_conv_system content block (bced0f9)
• session-runner: retry tool-result sends for at least the lease TTL (#299) (ebc9533)
• tool-runner: forward the server-assigned container on follow-up requests (#277) (860620c)
• toolrunner: don't yield the final message twice from All() (#314) (1e418f0)

Chores

• internal: remove leftover prism references (a1d9eab)

Full Changelog: v1.63.1...v1.64.0

Features

• api: additions to files and memory stores (5c105da)
• api: updates to skill, files, and user profiles (a0061d6)

Bug Fixes

• api: remove unsupported mid_conv_system content block (bced0f9)
• session-runner: retry tool-result sends for at least the lease TTL (#299) (ebc9533)
• tool-runner: forward the server-assigned container on follow-up requests (#277) (860620c)
• toolrunner: don't yield the final message twice from All() (#314) (1e418f0)

Chores

• internal: remove leftover prism references (a1d9eab)

1.63.1 (2026-08-13)

Full Changelog: v1.63.0...v1.63.1

Bug Fixes

• auth: pin token exchange to the configured base URL and skip auth for other origins (#258) (6e4141c)
• client: apply stop_details from every message_delta when accumulating (#253) (c197a64)
• client: properly render maxLength and maxItems in generated schemas (84a57f5)
• sessions: post "(no output)" for empty text tool results instead of an empty text block (#236) (a588842)

Chores

• ci: run breaking-change detection as a ci.yml job on every push (29aebdb)

Documentation

• api: clarify that user profile name is optional for resold profiles (1039f95)

Full Changelog: v1.63.0...v1.63.1

Bug Fixes

• auth: pin token exchange to the configured base URL and skip auth for other origins (#258) (6e4141c)
• client: apply stop_details from every message_delta when accumulating (#253) (c197a64)
• client: properly render maxLength and maxItems in generated schemas (84a57f5)
• sessions: post "(no output)" for empty text tool results instead of an empty text block (#236) (a588842)

Chores

• ci: run breaking-change detection as a ci.yml job on every push (29aebdb)

Documentation

• api: clarify that user profile name is optional for resold profiles (1039f95)

1.63.0 (2026-08-10)

Full Changelog: v1.62.0...v1.63.0

Features

• api: add output_behavior to dream creation (create a new memory store or update the input store in place) (ba999d5)

Bug Fixes

• client: add models (a662a31)
• symlink-loop paths, special archive members, and 409 retry in the agent toolset and environment worker (#226) (82aa034)
• vertex: preserve a user-supplied HTTP client by wrapping its transport with Google auth (#242) (8e85a8e)

Full Changelog: v1.62.0...v1.63.0

Features

• api: add output_behavior to dream creation (create a new memory store or update the input store in place) (ba999d5)

Bug Fixes

• client: add models (a662a31)
• symlink-loop paths, special archive members, and 409 retry in the agent toolset and environment worker (#226) (82aa034)
• vertex: preserve a user-supplied HTTP client by wrapping its transport with Google auth (#242) (8e85a8e)

1.62.0 (2026-08-06)

Full Changelog: v1.61.0...v1.62.0

Features

• api: add mid-conversation-tool-changes-2026-07-01 beta (f53c3d3)
• api: add support for session budgets, advisor tool, pinned inference location and skills auto-loading from GitHub (89c04c2)

Bug Fixes

• client: preserve wire-faithful JSON in accumulated streaming messages (#197) (9a01ac0)
• jsonl: prevent silent truncation of large results, and don't panic on close (#203) (77dd33d)
• tools: name tool refusals and a dead shell so they can be matched (#213) (da87d4d)

Chores

• api: remove retired Claude Opus 4.1 models (85fdf3b)
• docs: small updates to descriptions (487e6ea)
• docs: updates to a few documentation strings (03dc511)

Full Changelog: v1.61.0...v1.62.0

Features

• api: add mid-conversation-tool-changes-2026-07-01 beta (f53c3d3)
• api: add support for session budgets, advisor tool, pinned inference location and skills auto-loading from GitHub (89c04c2)

Bug Fixes

• client: preserve wire-faithful JSON in accumulated streaming messages (#197) (9a01ac0)
• jsonl: prevent silent truncation of large results, and don't panic on close (#203) (77dd33d)
• tools: name tool refusals and a dead shell so they can be matched (#213) (da87d4d)

Chores

• api: remove retired Claude Opus 4.1 models (85fdf3b)
• docs: small updates to descriptions (487e6ea)
• docs: updates to a few documentation strings (03dc511)

1.61.0 (2026-07-24)

Full Changelog: v1.60.0...v1.61.0

Features

• api: add claude-opus-5 model (bb7dc83)
• api: add tool addition/removal blocks and tool_change events (bb7dc83)
• api: expand client-side fallback credit token types and add server-side fallbacks default option (bb7dc83)

Full Changelog: v1.60.0...v1.61.0

Features

• api: add claude-opus-5 model (bb7dc83)
• api: add tool addition/removal blocks and tool_change events (bb7dc83)
• api: expand client-side fallback credit token types and add server-side fallbacks default option (bb7dc83)

1.60.0 (2026-07-23)

Full Changelog: v1.59.0...v1.60.0

Features

• api: add new stop reason 'model_context_window_exceeded' (94caa5d)

Bug Fixes

• apijson: correct unmarshaling for param types (#73) (661be2e)
• client: escape HTML in RawJSON overrides of nested properties (3b163e2)
• refer to the CLI as ant in auth error messages (#194) (d6508c7)

Full Changelog: v1.59.0...v1.60.0

Features

• api: add new stop reason 'model_context_window_exceeded' (94caa5d)

Bug Fixes

• apijson: correct unmarshaling for param types (#73) (661be2e)
• client: escape HTML in RawJSON overrides of nested properties (3b163e2)
• refer to the CLI as ant in auth error messages (#194) (d6508c7)

1.59.0 (2026-07-22)

Full Changelog: v1.58.1...v1.59.0

Features

• api: add support for Managed Agents model effort, initial session events, and threads delta streaming (abca19a)

Full Changelog: v1.58.1...v1.59.0

Features

• api: add support for Managed Agents model effort, initial session events, and threads delta streaming (abca19a)

1.58.1 (2026-07-21)

Full Changelog: v1.58.0...v1.58.1

Bug Fixes

• client: copy all citation fields in ToParam conversions (#191) (26ac1f9)
• vertex: default to the cloud-platform scope in WithGoogleAuth (#190) (7931e70)

Chores

• api: add support for new refusal category (f77159c)
• docs: small updates (576dc36)
• docs: small updates (f618082)
• internal: codegen related update (03fee5d)

Full Changelog: v1.58.0...v1.58.1

Bug Fixes

• client: copy all citation fields in ToParam conversions (#191) (26ac1f9)
• vertex: default to the cloud-platform scope in WithGoogleAuth (#190) (7931e70)

Chores

• api: add support for new refusal category (f77159c)
• docs: small updates (576dc36)
• docs: small updates (f618082)
• internal: codegen related update (03fee5d)

Full Changelog: v1.57.0...v1.58.0

Features

• api: add support for MCP Tunnels (3465b89)

Full Changelog: v1.56.0...v1.57.0

Features

• api: add support for dreaming (3736bf0)
• tools: gate session tool calls on evaluated_permission (#151) (4d85a6f)

Bug Fixes

• helpers: distinguish canonical agent.message events from open previews (#118) (c49c17c)

Chores

• docs: small updates to field descriptions (61bc396)
• docs: update model example (937a29c)
• docs: updates to descriptions and examples (2c59f79)

Full Changelog: v1.55.1...v1.56.0

Features

• api: add agent-memory-2026-07-22 beta header (5bcfda4)

Full Changelog: v1.55.0...v1.55.1

Chores

• api: remove some nonfunctional types from the SDKs (9bd3d09)

Full Changelog: v1.54.0...v1.55.0

Features

• api: add support for Managed Agents event delta streaming, agent overrides, reverse pagination, vault credential injection scoping, and agent and deployment webhook events (021ef45)

Full Changelog: v1.53.0...v1.54.0

Features

• api: add support for claude-sonnet-5 (232cfe6)

Bug Fixes

• agenttoolset: allow absolute paths that resolve inside workdir (#93) (3735258)

Full Changelog: v1.52.0...v1.53.0

Features

• api: add support for 20260318 web fetch and support tools (6396455)

Chores

• api: accept user profile ID's when counting tokens (d31ba27)
• docs: updates to descriptions and example values (cb00f34)

Full Changelog: v1.51.1...v1.52.0

Features

• client: add support for system.message streaming events (7bb296d)

Chores

• api: add support for new refusal category (46f8625)
• api: add support for sending User Profile ID in request headers (5cab486)

Full Changelog: v1.51.0...v1.51.1

Bug Fixes

• helpers: single source for x-stainless-helper, append semantics, and tag the fallback middleware (#88) (ebbdb7d)

Full Changelog: v1.50.2...v1.51.0

Features

• api: add support for new code_execution_20260120 tool (f54a4a8)

Full Changelog: v1.50.1...v1.50.2

Chores

• api: remove retired models from API and SDKs (11f5c82)

Full Changelog: v1.50.0...v1.50.1

Bug Fixes

• api: add frontier_llm refusal category (9ebbaf7)

Full Changelog: v1.49.0...v1.50.0

Features

• api: add support for Managed Agents deployments and environment variable credentials (f72e1d8)

Full Changelog: v1.48.0...v1.49.0

Features

• api: add support for claude-mythos-5 and claude-fable-5, with support for server-side fallbacks on refusal (782f223)
• client: adds client-side fallbacks middleware for API providers that do not support server-side fallbacks (782f223)

Bug Fixes

• 3p middleware ordering (#38) (8f47086)

Full Changelog: v1.47.0...v1.48.0

Features

• api: small updates to Managed Agents types (3ebeea5)

Full Changelog: v1.46.0...v1.47.0

Features

• api: mark Claude Opus 4.1 as deprecated (64b20dc)
• require Go 1.24 (#11) (00fae19)

Bug Fixes

• streaming: accumulate content block events by index (#6) (2161a38)
• streaming: carry encrypted_content through beta compaction accumulator (#875) (13fa611)
• streaming: carry stop_details and usage fields through beta message_delta (#879) (d432c9f)
• streaming: carry stop_details and usage fields through message_delta (#877) (e2fcc35)
• support invopop/jsonschema v0.14.0 (switch to pb33f/ordered-map) (#10) (af018a7)

Chores

• internal: fix artifact url (fd4cde3)
• internal: fix branch names (e1730cd)
• internal: update private repo name (29f7468)

Documentation

• point security reports to Anthropic's HackerOne program (#9) (c143385)

Full Changelog: v1.45.0...v1.46.0

Features

• api: Add support for claude-opus-4-8, mid-conversation system blocks, and usage.output_tokens_details (4cd860b)
• support custom file size caps (#876) (99634e8)

Chores

• examples: rename managed-agents private-sandbox-worker to self-hosted-sandbox-worker (#873) (07d3e46)

Documentation

• replace literal newlines (cbb7ea5)

Full Changelog: v1.44.1...v1.45.0

Features

• api: Add support for thinking-token-count beta for estimated tokens in thinking block deltas when streaming (dedeb6d)

Full Changelog: v1.44.0...v1.44.1

Bug Fixes

• runner: skip tool calls SessionToolRunner does not own (93afc65)

Full Changelog: v1.43.0...v1.44.0

Features

• client: Add support for self-hosted sandboxes in CMA with sandbox helpers (34354c4)

Full Changelog: v1.42.0...v1.43.0

Features

• api: Add BetaManagedAgentsSearchResultBlock types (498fafc)
• api: Add support for cache diagnostics beta (eac032f)
• client: add compatibility aliases for old type names (38e1f89)
• client: add compatibility aliases for old type names (a98b0fb)
• client: optimize json encoder for internal types (f379c42)

Bug Fixes

• structured outputs: allowlist enum, const, pattern, allOf in transformSchema (#823) (d368786)

Chores

• api: spec updates (502b9f1)
• fix standard webhooks version (#842) (1fdda46)
• internal: simplify release-please config (69da3d6)

Full Changelog: v1.41.0...v1.42.0

Features

• aws: Add AWS client for Claude Platform on AWS (596baf4)

Bug Fixes

• examples: update examples dependencies (e832b79)
• go: avoid panic when http.DefaultTransport is wrapped (6b75bef)

Chores

• client: update dependency checksums (64c1d95)
• go mod tidy (#816) (09b5f9c)
• internal: codegen related update (6e83495)
• internal: codegen related update (34d1379)
• internal: codegen related update (c068475)
• redact api-key headers in debug logs (46a074f)
• redact api-key headers in debug logs (1fe2ebb)

Full Changelog: v1.40.0...v1.41.0

Features

• api: add support for Managed Agents multiagents and outcomes, webhooks, vault validation (33762b0)
• mcp: add mcp tool helpers (#752) (4edf9f5)

Bug Fixes

• api: Adjust webhook configuration (8b2f194)

Full Changelog: v1.39.0...v1.40.0

Features

• client: allow targeting a workspace for OIDC federation token exchange (6bf66ac)

Full Changelog: v1.38.0...v1.39.0

Features

• api: improve Managed Agents APIs (eadf509)
• client: add Workload Identity Federation, interactive OAuth, and auth profiles (0f0cc01)
• go: add default http client with timeout (b81c287)
• support setting headers via env (641015d)

Bug Fixes

• client: add 10 min timeout (#770) (917fe19)

Chores

• avoid embedding reflect.Type for dead code elimination (11168b4)

Full Changelog: v1.37.0...v1.38.0

Features

• add Type() method to API errors for error kind identification (#676) (0db1712)
• api: CMA Memory public beta (180e00c)
• structured outputs via Schema any with auto-parse (#759) (46073d8)

Bug Fixes

• api: fix errors in api spec (e47c178)
• api: restore missing features (0fc6fac)

Chores

• internal: more robust bootstrap script (5bde204)
• tests: bump steady to v0.22.1 (4578c15)

Full Changelog: v1.36.0...v1.37.0

Features

• api: add claude-opus-4-7, token budgets and user_profiles (6e758a9)

Full Changelog: v1.35.1...v1.36.0

Features

• api: mark Sonnet and Opus 4 as deprecated (fc49d21)
• bedrock: use auth header for mantle client (#734) (629eec1)

Full Changelog: v1.35.0...v1.35.1

Bug Fixes

• streaming: add missing events (227b83e)

Full Changelog: v1.34.0...v1.35.0

Features

• vertex eu region (#740) (e8bda03)

Bug Fixes

• tools: convert tool response type to array (#748) (3a18787)

Documentation

• update examples (aff7b24)

Full Changelog: v1.33.0...v1.34.0

Features

• api: Add beta advisor tool (3a6ddba)

Full Changelog: v1.32.0...v1.33.0

Features

• api: add support for Claude Managed Agents (722b2ac)

Full Changelog: v1.31.0...v1.32.0

Features

• bedrock: add AnthropicBedrockMantle client (#704) (058e8fa)

Full Changelog: v1.30.0...v1.31.0

Features

• api: Add support for claude-mythos-preview (7144a65)

Full Changelog: v1.29.0...v1.30.0

Features

• vertex: add support for US multi-region endpoint (6f40457)

Full Changelog: v1.28.0...v1.29.0

Features

• api: add structured stop_details to message responses (1053799)

Chores

• internal: client updates (531283d)

Full Changelog: v1.27.1...v1.28.0

Features

• internal: support comma format in multipart form encoding (97ed8a1)

Bug Fixes

• bump buger/jsonparser to v1.1.2 (GO-2026-4514) (#665) (96565eb)
• prevent duplicate ? in query params (0afa75c)
• types: generate shared enum types that are not referenced by other schemas (5dc86f2)

Chores

• ci: run builds on CI even if only spec metadata changed (010a16f)
• ci: skip lint on metadata-only changes (8cc7cec)
• ci: support opting out of skipping builds on metadata-only commits (adc7184)
• client: fix multipart serialisation of Default() fields (3fc3613)
• internal: bump go toolchain to go1.25.8 to address std lib vulnerabilities (e3feecb)
• internal: support default value struct tag (fc68556)
• internal: update gitignore (e2a5dd1)
• remove unnecessary error check for url parsing (6d42216)
• tests: bump steady to v0.19.4 (3ca1569)
• tests: bump steady to v0.19.5 (7364e49)
• tests: bump steady to v0.19.6 (28ebd01)
• tests: bump steady to v0.19.7 (77fc869)
• tests: bump steady to v0.20.1 (e52beb5)
• tests: bump steady to v0.20.2 (3a20191)
• update docs for api:"required" (aa0a03a)

Full Changelog: v1.27.0...v1.27.1

Chores

• internal: regenerate SDK with no functional changes (c963fd0)
• internal: tweak CI branches (95e3410)

Full Changelog: v1.26.0...v1.27.0

Features

• api: change array_format to brackets (ca5ae6e)
• api: chore(config): clean up model enum list (#31) (1db4ea7)
• api: GA thinking-display-setting (1924af2)
• api: remove publishing section from cli target (514282e)
• tests: update mock server (cf24ced)

Bug Fixes

• allow canceling a request while it is waiting to retry (32ee053)
• client: update model reference from claude-3-7-sonnet-latest to claude-sonnet-4-5 (2f42e73)

Chores

• client: reorganize code in Messages files to lead to less conflicts (c677bb5)
• internal: codegen related update (c978aac)
• internal: codegen related update (4ac31a2)
• internal: codegen related update (5b2b2fa)
• internal: codegen related update (9678c6c)
• internal: codegen related update (f6035d2)
• internal: codegen related update (9246bbb)
• internal: move custom custom json tags to api (4392627)
• tests: unskip tests that are now supported in steady (b0ca374)

Documentation

• streamline README, centralize documentation at docs.anthropic.com (33f6943), closes #587

Full Changelog: v1.25.1...v1.26.0

Features

• api: Add top-level cache control (automatic caching) (75f9f70)
• client: add BetaToolRunner for automatic tool use loops (#603) (e44128a)

Chores

• internal: codegen related update (6247d2f)

Full Changelog: v1.25.0...v1.25.1

Bug Fixes

• client: use correct format specifier for header serialization (9115a61)

Full Changelog: v1.24.0...v1.25.0

Features

• api: fix shared UserLocation and error code types (cb98cd0)

Full Changelog: v1.23.0...v1.24.0

Features

• api: manual updates (54d01f5)

Full Changelog: v1.22.1...v1.23.0

Features

• api: Releasing claude-sonnet-4-6 (782d5a5)

Bug Fixes

• api: fix spec errors (15e6a5a)
• remove duplicate ServerToolUseBlock struct declaration (#595) (d4ece8a)