langchain-core==1.3.0a1

LangChain Releases / 4/11/2026

📰 NewsDeveloper Stack & InfrastructureTools & Practical Usage

Key Points

  • langchain-core のバージョン 1.3.0a1 が初回リリースされました。
  • streaming に関するメタデータ削減などのパフォーマンス改善が含まれています。
  • テンプレートのサニタイズ強化や、非推奨プロンプト保存パスでのシンボリックリンク対応などの修正が入っています。
  • 併せて過去の 1.2.x 系リリース(1.2.28/1.2.27/1.2.26 等)に関連する更新も言及されています。

Initial release

release(core): 1.3.0a1 (#36656)
chore(core): reduce streaming metadata / perf (#36588)
release(core): release 1.2.28 (#36614)
fix(core): add more sanitization to templates (#36612)
release(core): 1.2.27 (#36586)
fix(core): handle symlinks in deprecated prompt save path (#36585)
chore: add comment explaining pygments>=2.20.0 (#36570)
release(core): 1.2.26 (#36511)
fix(core): add init validator and serialization mappings for Bedrock models (#34510)
feat(core): add ChatBaseten to serializable mapping (#36510)
chore(core): drop gpt-3.5-turbo from docstrings (#36497)
fix(core): correct parameter names in filter_messages docstring example (#36462)
release(core): 1.2.25 (#36473)
fix(core): harden check for txt files in deprecated prompt loading functions (#36471)
fix(core): fixed typos in the documentation (#36459)
release(core): 1.2.24 (#36434)
feat(core): impute placeholder filenames for OpenAI file inputs (#36433)
chore: pygments>=2.20.0 across all packages (CVE-2026-4539) (#36385)
fix(core): add "computer" to _WellKnownOpenAITools (#36261)
release(core): 1.2.23 (#36323)
revert: Revert "fix(core): trace invocation params in metadata" (#36322)
chore: bump requests from 2.32.5 to 2.33.0 in /libs/core (#36243)
release(core): 1.2.22 (#36201)
fix(core): validate paths in prompt.save and load_prompt, deprecate methods (#36200)
release(core): 1.2.21 (#36179)
fix(core,model-profiles): add missing ModelProfile fields, warn on schema drift (#36129)
chore(core): remove stale blockbuster allowlist for deleted context module (#36168)
ci: suppress pytest streaming output in CI (#36092)
release(core): 1.2.20 (#36085)
fix(core): trace invocation params in metadata (#36080)
feat: Add LangSmith integration metadata to create_agent and init_chat_model (#35810)
feat(core): harden anti-ssrf (#35960)
ci: avoid unnecessary dep installs in lint targets (#36046)
docs(core): document base_url in mermaid api (#35961)
chore: bump orjson from 3.11.5 to 3.11.6 in /libs/core (#35805)
chore: housekeeping (#35850)
release(core): 1.2.19 (#35832)
chore(core): move BaseCrossEncoder to langchain-core (#35809)
chore: bump tornado from 6.5.2 to 6.5.5 in /libs/core (#35775)
release(core): 1.2.18 (#35704)
fix(core): fix double backticks in deprecation docstring for alternative_import (#35658)
fix(core): preserve default_factory when generating tool call schema (#35550)
feat(openai): support tool search (#35582)
chore: bump the minor-and-patch group across 3 directories with 7 updates (#35605)
release(core): 1.2.17 (#35527)
fix(core): extract usage metadata from serialized tracer message outputs (#35526)
chore: bump the langchain-deps group across 3 directories with 7 updates (#35513)
chore: bump the langchain-deps group across 3 directories with 14 updates (#35441)
release(core): 1.2.16 (#35439)
fix(core): treat empty tool chunk ids as missing in merge (#35414)
fix(core): improve error message for non-JSON-serializable tool schemas (#34376)
fix(core): improve typing/docs for on_chat_model_start to clarify required positional args (#35324)
perf(core): defer specific langsmith imports to reduce import time (#35298)
revert: add ChatAnthropicBedrockWrapper (#35371)
release(core): 1.2.15 (#35367)
fix(anthropic): replace retired model IDs in tests and docstrings (#35365)
feat(anthropic): add ChatAnthropicBedrock wrapper (#35091)
style: fix some ruff noqa (#35321)
release(core): 1.2.14 (#35328)
chore(core): remove langserve from sys info util, add deepagents (#35325)
fix(core): fix merge_lists incorrectly merging parallel tool calls (#35281)
fix(core): accept int temperature in _get_ls_params for LangSmith tracing (#35302)
revert: accept integer temperature values in _get_ls_params (#35319)
fix(core): accept integer temperature values in _get_ls_params (#35317)
docs(core): update load note to be precise (#35309)
fix(core): prevent recursion error when args_schema is dict (#35260)
fix(core): preserve index and timestamp fields when merging (#34731)
docs(core): add security warnings and best practices for deserialization (#35282)
docs: fix docstring inaccuracies and update outdated LangSmith URLs (#35283)
fix(core): correct misleading jinja2 sandboxing comment (#35183)
chore: bump the langchain-deps group across 3 directories with 8 updates (#35257)
release(core): 1.2.13 (#35230)
docs(core): expanded get_lc_namespace docstring (#35229)
feat(openrouter): add langchain-openrouter provider package (#35211)
style: bump ruff version to 0.15 (#35042)
release(core): 1.2.12 (#35192)
fix(core): fix setting ChatGeneration.text (#35191)
release(core): 1.2.11 (#35144)
fix(openai): sanitize urls when counting tokens in images (#35143)
chore(core): clean up docstring mismatch and redundant logic in langchain-core (#35064)
fix(core): replace bare except with Exception in tracer (#35138)
release(core): 1.2.10 (#35136)
chore(deps): bump the langchain-deps group across 3 directories with 40 updates (#35129)
chore(deps): bump the langchain-deps group across 3 directories with 11 updates (#35121)
feat(core): add ContextOverflowError, raise in anthropic and openai (#35099)
feat(model-profiles): add text_inputs and text_outputs (#35084)
feat(core): count tokens from tool schemas in count_tokens_approximately (#35098)
docs(core): add missing name docstring for RunnableSerializable (#35088)
release(core): 1.2.9 (#35025)
fix(core): adjust cap when scaling approximate token counts (#35017)
revert: precompile hex color regex pattern at module level (#35016)
chore: add make type target (#35015)
revert: "chore: add typing target in Makefile" (#35013)
chore: add typing target in Makefile (#35012)
fix(core): apply cap when scaling approximate token counts (#35005)
feat(core): allow scaling by reported usage when counting tokens approximately (#34996)
test(core): increase delta_time for flaky test (#34982)
chore: enrich pyproject.toml files (#34980)
release(core): 1.2.8 (#34975)
docs(core): add examples for pretty_repr, pretty_print (#34968)
docs(core): use proper admonition for get_buffer_string (#34967)
docs: add usage examples to core classes (#34841)
chore(core): fix docstring format (#34966)
chore(deps): bump the uv group across 20 directories with 3 updates (#34941)
docs: add example to create_message function docstring (#34851)
docs(core): clarify tool decorator argument and return type requirements (#34860)
fix(core): fix nested mustache variable extraction and update docs (#34872)
fix(core): allow base model annotations for empty model (#34932)
chore: upgrade urllib3 to 2.6.3 (#34940)
fix(core): prevent crash in ParrotFakeChatModel when messages list is empty (#34943)
fix(core): google docstring parsing with no arguments/reserved arguments (#34861)
test(core): add tests for approximate token counting with multimodal messages (#34898)
fix(core): replace Iterable with Iterator for block iteration (#34934)
fix(core): yield_blobs returns Iterator (#34935)
docs: Fix typo in Runnable description of async variants (#34905)
fix(core): raise outputparserexception for unknown tools (#34923)
docs(core): nit (#34914)
chore(core): nits (#34897)
feat(core): add multimodal support to count_tokens_approximately (#34883)
fix(core): fix typo 'use a a' -> 'use as a' in check_version.py (#34878)
style(core): lint (#34862)
feat(core): add XML format option for get_buffer_string (#34802)
chore(core): relax packaging constraints (#34832)
chore(deps-dev): bump setuptools from 67.8.0 to 78.1.1 in /libs/core in the uv group across 1 directory (#34825)
chore(core, langchain): add version consistency check pre-commit hooks (#34782)
docs(core): enhance docstring for RunnableConfig for clarity on total=False (#34756)
docs(core): clean up callbacks param descriptions (#34738)
fix(core): correctly guard against non-text-block types (#34729)
chore: update twitter URLs (#34736)
refactor(core): generalize comma_list utility to support any Iterable (#34714)
fix(core): add explicit tags parameter to sync LLMManagerMixin methods (#34722)
docs(core): enhance docstrings for ToolCall and ToolCallChunk (#34719)
fix(core): add tool_call_id to on_tool_error event data (#33731)
fix(core): improve error message for missing title in JSON schema functions (#34683)
fix(core): make yield_keys prefix keyword-only to match BaseStore (#34659)
chore(core): bump lock (#34695)
chore(core): improve types for RunnableLambda (#34539)
chore(core): improve types for StreamingRunnable (#34540)
style(core): fix some noqa escapes (#34675)
style: bump ruff version to 0.14.11 (#34674)
fix: remove relative imports (#34680)
release: langchain-core 1.2.7 (#34678)
fix: don't trace injected args only found in signature (#34670)
feat(core): add more file extensions to ignore in HTML link extraction (#34552)
refactor(core): improve docstrings for HTML link extraction utilities (#34550)
test(core): add edge case for empty examples in LengthBasedExampleSelector (#34641)
fix(core): fix strict schema generation for functions with optional args (#34599)
feat(core): support custom message separator in get_buffer_string() (#34569)
refactor(core): add warning for fallback GPT-2 tokenizer usage (#34621)
fix(core,langchain): use get_buffer_string for message summarization (#34607)
test(core): add tests for formatting utils and merge functions (#34511)
fix(core): strip message IDs from cache keys using model_copy (#33915)
fix(core): exclude injected args from tool schema (#34582)
refactor(core): select chunk_id via ranking and remove extra allocation (#34588)
release(core): 1.2.6 (#34586)
chore(core): Update LangChainTracer to use Pydantic v2 methods (#34541)
docs(core): add docstrings to internal helper functions (#34525)
docs(core): refresh content.py docstrings (#34546)
chore(deps): bump mypy to v1.19 and ruff to v1.14 (#34521)
refactor(core): fix some missing generic types (#31658)
style(core): add ruff RUF012 rule (#34492)
fix(core): support (message class, template) tuples in ChatPromptTemplate.from_messages (#33989)
test(core): add regression test for list-index $ref resolution (#34097)
fix(core): fix callback manager merge mixing handlers (#32028) (#33617)
style: add ruff ISC001 rule (#34493)
style(core): fix mypy no-any-return violations (#34204)
docs(core): image url docstring enhancement (#34488)
test(core): URL-encode bgColor parameter in mermaid.ink API calls (#34466)
style(core): fix some noqa: ARG rules (#34437)
fix(core): URL-encode bgColor in mermaid API calls (#34461)
perf(core): move origin type map to module level in function_calling.py (#34481)
style(core): add ruff rules TC (#34476)
perf(core): precompile hex color regex pattern at module level (#34480)
docs(core): update to indicate betas (#34457)
release(core): 1.2.5 (#34456)
fix(core): serialization patch (#34455)
fix(core): RunnablePick method return types (#34208)
fix(core): preserve Field(description=...) in @tool decorator (#34354)
fix(core): populate default args from tool's args_schema (#34399)
fix(core): use tool_calls instead of deprecated function_call in get_buffer_string (#34355)
feat(core): add PEP 702 __deprecated__ attribute support to @deprecated (#34257)
fix(core): ensure tool_call_count is never null (#34431)
feat(core): automatically count and store meta for tool call count (#33756)
feat(core): add 'approximate' alias in place of count_tokens_approximately (#33045)
chore(core): fix some ruff preview rules (#34425)
release(core): 1.2.4 (#34429)
feat(core): add usage_metadata to metadata in LangChainTracer (#34414)
fix(core): defer persisting traces for iterator inputs (#34416)
chore(core): fix some docstrings (#34426)
release(core): 1.2.3 (#34421)
fix(core): allow unknown blocks in convert_to_openai_messages (#34420)
feat(infra): add CI check for out of date lockfiles (#34397)
chore(core): bump lockfile (#34392)
release(core): 1.2.2 (#34391)
fix(core): use get_type_hints for Python 3.14 TypedDict compatibility (#34390)
release(core): 1.2.1 (#34370)
fix(core): handle None arguments in parse_tool_call (#34242)
chore(core): fix some types related to ToolCallChunk (#34283)
release(core): 1.2 (#34319)
style(core): docs nit (#34312)
fix(core): widen openai tool/function conversion input type to Mapping (#34304)
chore(core): add admonitions around use of load (#34285)
feat(core,anthropic): extras on BaseTool (#34120)
release: langchain-core 1.1.3 (#34266)
fix(core): undo jinja2 restrictions (#34072)
fix: remove partial usage for retriever func + afunc (#34265)
release(core): 1.1.2 (#34253)
fix(core): pass tool_call_id to on_tool_start callback (#34235)
chore(core): improve typing of messages utils functions (#34225)
fix(core): prevent async task garbage collection (RUF006) (#34238)
chore(core): use anext and deprecate py_anext (#34211)
feat(core): support google maps grounding in genai block translator (#34244)
docs(core,groq,openai): nits for ref docs (#34243)
docs(core): improve style for refs (#34227)
docs(core): update StrOutputParser docstring (#34213)
release: langchain-core 1.1.1 (#34212)
feat: Use uuid7 for run ids (#34172)
fix: tool call id bug introduced w/ runtime injection (#34185)
chore: update test to be compatible with mem-optimized runtree (#34176)
docs(core): update docstrings in RunnableConfig, dereference_refs (#34131)
docs(anthropic,core,langchain): updates (#34106)
style(core,langchain,qdrant): fix some docstrings for refs (#34105)
fix(core): handle missing StructuredPrompt schema (#34096)
fix(core): ensure_ascii=False in PydanticOutputParser exception formatting (#34006)
fix(infra,core): nits (#34079)
style(core,langchain-classic,openai): fix griffe warnings (#34074)
chore(docs): fix a few refs syntax errors (#34044)
release(core): 1.1.0 (