[dependabot]

Bumps @langchain/anthropic from 1.3.5 to 1.6.0.

Release notes

Sourced from @​langchain/anthropic's releases.

@​langchain/anthropic@​1.6.0

Minor Changes

• #11986 2caf64d Thanks @​richardscarrott! - feat: stream tool-call args as tool-call-delta slices

  Tool-call and server-tool-call args now stream as tool-call-delta events, which carry only the new slice of the args, instead of block-delta snapshots of the args so far. A large tool call now costs about the same bytes on the wire as the same length of text.

  • This covers the compat bridge (any model that only implements _streamResponseChunks), the OpenAI-compatible converter (OpenAI Completions, Groq, Mistral, IBM, OpenRouter, Perplexity, DeepSeek, Fireworks, Together AI and xAI Completions), OpenAI and xAI Responses, Anthropic (client and server tool calls) and Bedrock Converse. Google and Ollama still send one complete snapshot per call.
  • A tool call's id, name and index go on content-block-start, which carries no args. An id or name that arrives later reaches consumers on content-block-finish.
  • If you read raw events and their block-delta fields.args mid-stream, or write agent stream transformers that do, read tool-call-delta instead. await stream, .toolCalls and the assembled message are unchanged.
  • Upgrade your clients first. Older clients mishandle tool-call-delta. You need @langchain/langgraph-sdk 1.12.6 or later; @langchain/react, @langchain/vue, @langchain/svelte or @langchain/angular 1.2.6 or later; and langchain-core 1.6.13 or later for Python clients.
  • To hold back, pin @langchain/core below 1.3.0. That also keeps you on @langchain/openai, @langchain/anthropic, @langchain/aws and @langchain/xai versions that send snapshots.

@​langchain/anthropic@​1.5.13

Patch Changes

• #11922 d71c542 Thanks @​richardscarrott! - feat(anthropic): declare mid-conversation support in model profiles. Claude Opus 4.8, Opus 5, Opus 5.5, Sonnet 5.5, Haiku 5.5, Fable 5 and 5.1, and Mythos 5 and 5.1 set midConversationSystemMessages and midConversationTools. Sonnet 5 sets system messages only.

  Regenerating the profiles from models.dev also adds Claude Opus 5.5, Sonnet 5.5 and Haiku 5.5, removes Claude Opus 4.1, and lowers Claude Sonnet 4.5's maxInputTokens to 200,000.

@​langchain/anthropic@​1.5.12

Patch Changes

• #11707 4109812 Thanks @​richardscarrott! - feat(anthropic): support mid-conversation tool changes. A SystemMessage can now carry Anthropic's tool_addition and tool_removal blocks, either bare in content or wrapped in a non_standard block, and they reach the provider verbatim. The required beta is added automatically: mid-conversation-tool-changes-2026-07-01 for tools named by reference, or inline-tools-2026-09-15 when a tool_addition defines a tool by value (tool: { type: "tool_definition", definition }).

  System content is now narrowed to what Anthropic accepts there. text, tool_addition and tool_removal are sent; any other block is dropped instead of being forwarded for the provider to reject. A system message left with no content is omitted.

@​langchain/anthropic@​1.5.11

Patch Changes

• #11669 fb2a9f3 Thanks @​richardscarrott! - feat(anthropic): accept a SystemMessage anywhere in the message list. Previously only the first message could be a system message. Anything else threw.

  A system message that isn't first is now sent at its own position. It applies from that point in the conversation onwards, and adding one leaves the prompt cache for the earlier turns intact.

  Two smaller changes come with it. A leading run of two or more SystemMessages now merges into the top-level system field instead of being rejected. System content built from standard content blocks no longer sends the internal block id to the provider.

Commits

• 38eb4d8 chore: version packages (#12018)
• dae3b1f chore(core): fill in client versions in tool-call-delta changeset (#12019)
• 2caf64d feat(core,openai,anthropic,aws,xai): stream tool-call args as `tool-call-delt...
• 8a008ea test(core): accept either order of a chunk's stream events in chat model chai...
• f65acc3 chore(deps): restore missing @modelcontextprotocol/core@2.3.0 lockfile entr...
• 6a0ab38 chore: version packages (#12008)
• 654c7c6 chore(deps-dev): bump @​modelcontextprotocol/server from 2.3.0 to 2.3.1 (#12005)
• f096a32 fix(langchain): deliver final answers after todo updates (#11989)
• c690992 fix: update Node.js to October 2026 security release (#12007)
• 0c5e7bc fix(langchain): avoid full-state copies in parallel tool tasks (#11990)
• Additional commits viewable in compare view

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