@langchain/core 1.0.0: predict and predictMessages removed, and what else went

@langchain/core 1.0.0 sits under every v1 provider package, so a repository picks it up when it upgrades @langchain/openai, @langchain/anthropic or langchain. What breaks: the pre-LCEL entry points on a chat model, four legacy subpaths, and 24 named exports the 0.3.x declaration files carried and 1.0.0 does not.

What changed

predict and predictMessages are gone from chat models. Both were deprecated in favour of invoke long before v1. Emendant attributes the calls through the provider packages, so a call on a ChatOpenAI, ChatAnthropic, ChatGoogleGenerativeAI or @langchain/community model is reported.
Four legacy subpaths were removed. runnables/remote, tracers/initialize, tracers/tracer_langchain_v1 and the two utils/hash utilities, all superseded by LangSmith’s tracing, none with a replacement.
24 named exports were removed. Found by diffing the two packages’ declaration files, not the migration guide, which does not list them. Most are content block and *FieldsWith* types in @langchain/core/messages; the rest include getCacheKey, TraceGroup, traceAsGroup, createChatMessageChunkEncoderStream, LoadOptions, SerializableLike, BaseStoreInterface, getRuntimeEnvironmentSync and insecureHash.
29 more gained a deprecation marker. They still work at this release. The is*Message and is*Block guards are most of them, along with MessageContentComplex, MessageContentText, MessageContentImageUrl, ImageDetail, ProviderFormatTypes, StandardContentBlockConverter, convertToOpenAIImageBlock, convertToProviderContentBlock, parseBase64DataUrl and parseMimeType. The table below names each one.
load() lost two options. secretsFromEnv and maxDepth are no longer declared on the second argument of load from @langchain/core/load. These two are reported at the key in the options object rather than at an import, so they fire on code whose imports are already correct.

Before and after

The two pre-LCEL calls on models held in variables, which is what makes the receiver attributable:

import { ChatAnthropic } from '@langchain/anthropic';
import { ChatOpenAI } from '@langchain/openai';

const openai = new ChatOpenAI({ model: 'gpt-4o' });
const anthropic = new ChatAnthropic({ model: 'claude-sonnet-4-5' });

export async function summarise(text: string): Promise<string> {
  return openai.predict(text);
}

export async function reply(messages: never[]) {
  return anthropic.predictMessages(messages);
}

The migration is to invoke, which returns a message. The string-returning call reads its text; the other is a rename:

export async function summarise(text: string): Promise<string> {
  return (await openai.invoke(text)).text;
}

export async function reply(messages: never[]) {
  return anthropic.invoke(messages);
}

A plain rename would typecheck in the second case and silently change the return type in the first, which is why this is an assisted patch rather than a transform.

The removed and newly deprecated names carry an assisted fix too, and what each one needs is a different question. Several of the content block types have a public successor in the 1.0 message types and rewrite cleanly; the tracing exports and the two hash utilities have no successor in the package at all, and require a developer to choose a replacement.

Migration guidance and its limits

Fifty-six of the fifty-seven findings carry an assisted fix, so a model provider named on the command line or in emendant.json is what turns this scan into patches. Without one every finding is reported with its guidance and nothing is sent anywhere. Review the suggested patches before applying them.

Read what comes back rather than applying it wholesale, because the release does not answer every one of these the same way. The predict migration changes a return type as well as a name, so let your typecheck confirm the patch followed what invoke returns. A content block type with a public successor in the 1.0 message types rewrites cleanly. The tracing exports, the two hash utilities and the removed load() options have no successor inside the package. Review their role in your application and choose a replacement where needed; these sites may have no patch. Whether your code needed a removed content block type at all is still a question about your code, and no entry here claims to know.

The four removed subpaths are the one report-only finding. Nothing in @langchain/core replaces runnables/remote, tracers/initialize, tracers/tracer_langchain_v1 or the two utils/hash utilities: LangSmith’s own tracing superseded them, which is a different package rather than a different import.

The 29 deprecations keep working in this release. Schedule their migration and check that each replacement preserves the behaviour your application needs.

The langchain package’s own reduction is on LangChain 1.0: the legacy modules moved to @langchain/classic. Upgrade the two packages together. Behaviour changes in the v1 message model that keep the same names are not in this entry.

What Emendant detects, fixes and verifies

57 changes in @langchain/core 1.0.0. 0 automatic fixes, 56 fixes requiring a model provider you choose, 1 report only. Each patch states which checks passed. Understand patch evidence.

Change	Severity	Detects	Fix	Verified by
predict and predictMessages removed from chat models `langchain-core-npm-1.0.0-chat-model-predict-removed`	Breaking	`.predict()` on an instance constructed from `@langchain/openai` `.predictMessages()` on an instance constructed from `@langchain/openai` `.predict()` on an instance constructed from `@langchain/anthropic` `.predictMessages()` on an instance constructed from `@langchain/anthropic` `.predict()` on an instance constructed from `@langchain/google-genai` `.predictMessages()` on an instance constructed from `@langchain/google-genai` `.predict()` on an instance constructed from `@langchain/community` `.predictMessages()` on an instance constructed from `@langchain/community`	Patch, only when you name a model provider	Your typecheck and tests
Four legacy core subpaths were removed `langchain-core-npm-1.0.0-legacy-subpaths-removed`	Breaking	any import of `@langchain/core/runnables/remote` any import of `@langchain/core/tracers/initialize` any import of `@langchain/core/tracers/tracer_langchain_v1` any import of `@langchain/core/utils/hash/insecure` any import of `@langchain/core/utils/hash/sha256`	Report only	Not applicable
Removed getCacheKey `langchain-core-npm-1.0.0-caches-get-cache-key-removed` `error TS2305: Module '"@langchain/core/caches"' has no exported member 'getCacheKey'.`	Breaking	`getCacheKey` imported from `@langchain/core/caches`	Patch, only when you name a model provider	Your typecheck and tests
Removed TraceGroup `langchain-core-npm-1.0.0-callbacks-manager-trace-group-removed` `error TS2305: Module '"@langchain/core/callbacks/manager"' has no exported member 'TraceGroup'.`	Breaking	`TraceGroup` imported from `@langchain/core/callbacks/manager`	Patch, only when you name a model provider	Your typecheck and tests
Removed traceAsGroup `langchain-core-npm-1.0.0-callbacks-manager-trace-as-group-removed` `error TS2305: Module '"@langchain/core/callbacks/manager"' has no exported member 'traceAsGroup'.`	Breaking	`traceAsGroup` imported from `@langchain/core/callbacks/manager`	Patch, only when you name a model provider	Your typecheck and tests
Removed createChatMessageChunkEncoderStream `langchain-core-npm-1.0.0-language-models-chat-models-create-chat-message-chunk-encoder-stream-removed` `error TS2305: Module '"@langchain/core/language_models/chat_models"' has no exported member 'createChatMessageChunkEncoderStream'.`	Breaking	`createChatMessageChunkEncoderStream` imported from `@langchain/core/language_models/chat_models`	Patch, only when you name a model provider	Your typecheck and tests
Removed LoadOptions `langchain-core-npm-1.0.0-load-load-options-removed` `error TS2305: Module '"@langchain/core/load"' has no exported member 'LoadOptions'.`	Breaking	`LoadOptions` imported from `@langchain/core/load`	Patch, only when you name a model provider	Your typecheck and tests
Removed SerializableLike `langchain-core-npm-1.0.0-load-serializable-serializable-like-removed` `error TS2724: '"@langchain/core/load/serializable"' has no exported member named 'SerializableLike'. Did you mean 'Serializable'?`	Breaking	`SerializableLike` imported from `@langchain/core/load/serializable`	Patch, only when you name a model provider	Your typecheck and tests
Removed Base64ContentBlock `langchain-core-npm-1.0.0-messages-base64-content-block-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'Base64ContentBlock'. Did you mean 'isBase64ContentBlock'?`	Breaking	`Base64ContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed BaseDataContentBlock `langchain-core-npm-1.0.0-messages-base-data-content-block-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'BaseDataContentBlock'. Did you mean 'isDataContentBlock'?`	Breaking	`BaseDataContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed ChatMessageFieldsWithRole `langchain-core-npm-1.0.0-messages-chat-message-fields-with-role-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'ChatMessageFieldsWithRole'. Did you mean 'MessageFieldWithRole'?`	Breaking	`ChatMessageFieldsWithRole` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed DataContentBlock `langchain-core-npm-1.0.0-messages-data-content-block-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'DataContentBlock'. Did you mean 'isDataContentBlock'?`	Breaking	`DataContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed DataContentBlockType `langchain-core-npm-1.0.0-messages-data-content-block-type-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'DataContentBlockType'. Did you mean 'isDataContentBlock'?`	Breaking	`DataContentBlockType` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed FunctionMessageFieldsWithName `langchain-core-npm-1.0.0-messages-function-message-fields-with-name-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'FunctionMessageFieldsWithName'. Did you mean 'FunctionMessageFields'?`	Breaking	`FunctionMessageFieldsWithName` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed IDContentBlock `langchain-core-npm-1.0.0-messages-idcontent-block-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'IDContentBlock'. Did you mean 'ContentBlock'?`	Breaking	`IDContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed PlainTextContentBlock `langchain-core-npm-1.0.0-messages-plain-text-content-block-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'PlainTextContentBlock'. Did you mean 'isPlainTextContentBlock'?`	Breaking	`PlainTextContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed StandardAudioBlock `langchain-core-npm-1.0.0-messages-standard-audio-block-removed` `error TS2305: Module '"@langchain/core/messages"' has no exported member 'StandardAudioBlock'.`	Breaking	`StandardAudioBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed StandardFileBlock `langchain-core-npm-1.0.0-messages-standard-file-block-removed` `error TS2305: Module '"@langchain/core/messages"' has no exported member 'StandardFileBlock'.`	Breaking	`StandardFileBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed StandardImageBlock `langchain-core-npm-1.0.0-messages-standard-image-block-removed` `error TS2305: Module '"@langchain/core/messages"' has no exported member 'StandardImageBlock'.`	Breaking	`StandardImageBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed StandardTextBlock `langchain-core-npm-1.0.0-messages-standard-text-block-removed` `error TS2305: Module '"@langchain/core/messages"' has no exported member 'StandardTextBlock'.`	Breaking	`StandardTextBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed ToolMessageFieldsWithToolCallId `langchain-core-npm-1.0.0-messages-tool-message-fields-with-tool-call-id-removed` `error TS2305: Module '"@langchain/core/messages"' has no exported member 'ToolMessageFieldsWithToolCallId'.`	Breaking	`ToolMessageFieldsWithToolCallId` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed URLContentBlock `langchain-core-npm-1.0.0-messages-urlcontent-block-removed` `error TS2724: '"@langchain/core/messages"' has no exported member named 'URLContentBlock'. Did you mean 'isURLContentBlock'?`	Breaking	`URLContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed ToolMessageFieldsWithToolCallId `langchain-core-npm-1.0.0-messages-tool-tool-message-fields-with-tool-call-id-removed` `error TS2305: Module '"@langchain/core/messages/tool"' has no exported member 'ToolMessageFieldsWithToolCallId'.`	Breaking	`ToolMessageFieldsWithToolCallId` imported from `@langchain/core/messages/tool`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isToolMessage `langchain-core-npm-1.0.0-messages-tool-is-tool-message-deprecated`	Deprecation	`isToolMessage` imported from `@langchain/core/messages/tool`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isToolMessageChunk `langchain-core-npm-1.0.0-messages-tool-is-tool-message-chunk-deprecated`	Deprecation	`isToolMessageChunk` imported from `@langchain/core/messages/tool`	Patch, only when you name a model provider	Your typecheck and tests
Removed BaseStoreInterface `langchain-core-npm-1.0.0-stores-base-store-interface-removed` `error TS2305: Module '"@langchain/core/stores"' has no exported member 'BaseStoreInterface'.`	Breaking	`BaseStoreInterface` imported from `@langchain/core/stores`	Patch, only when you name a model provider	Your typecheck and tests
Removed getRuntimeEnvironmentSync `langchain-core-npm-1.0.0-utils-env-get-runtime-environment-sync-removed` `error TS2724: '"@langchain/core/utils/env"' has no exported member named 'getRuntimeEnvironmentSync'. Did you mean 'getRuntimeEnvironment'?`	Breaking	`getRuntimeEnvironmentSync` imported from `@langchain/core/utils/env`	Patch, only when you name a model provider	Your typecheck and tests
Removed insecureHash `langchain-core-npm-1.0.0-utils-hash-insecure-hash-removed` `error TS2305: Module '"@langchain/core/utils/hash"' has no exported member 'insecureHash'.`	Breaking	`insecureHash` imported from `@langchain/core/utils/hash`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated ImageDetail `langchain-core-npm-1.0.0-messages-image-detail-deprecated`	Deprecation	`ImageDetail` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated MessageContentComplex `langchain-core-npm-1.0.0-messages-message-content-complex-deprecated`	Deprecation	`MessageContentComplex` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated MessageContentImageUrl `langchain-core-npm-1.0.0-messages-message-content-image-url-deprecated`	Deprecation	`MessageContentImageUrl` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated MessageContentText `langchain-core-npm-1.0.0-messages-message-content-text-deprecated`	Deprecation	`MessageContentText` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated ProviderFormatTypes `langchain-core-npm-1.0.0-messages-provider-format-types-deprecated`	Deprecation	`ProviderFormatTypes` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated StandardContentBlockConverter `langchain-core-npm-1.0.0-messages-standard-content-block-converter-deprecated`	Deprecation	`StandardContentBlockConverter` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated convertToOpenAIImageBlock `langchain-core-npm-1.0.0-messages-convert-to-open-aiimage-block-deprecated`	Deprecation	`convertToOpenAIImageBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated convertToProviderContentBlock `langchain-core-npm-1.0.0-messages-convert-to-provider-content-block-deprecated`	Deprecation	`convertToProviderContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isAIMessage `langchain-core-npm-1.0.0-messages-is-aimessage-deprecated`	Deprecation	`isAIMessage` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isAIMessageChunk `langchain-core-npm-1.0.0-messages-is-aimessage-chunk-deprecated`	Deprecation	`isAIMessageChunk` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isBase64ContentBlock `langchain-core-npm-1.0.0-messages-is-base64-content-block-deprecated`	Deprecation	`isBase64ContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isBaseMessage `langchain-core-npm-1.0.0-messages-is-base-message-deprecated`	Deprecation	`isBaseMessage` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isBaseMessageChunk `langchain-core-npm-1.0.0-messages-is-base-message-chunk-deprecated`	Deprecation	`isBaseMessageChunk` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isChatMessage `langchain-core-npm-1.0.0-messages-is-chat-message-deprecated`	Deprecation	`isChatMessage` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isChatMessageChunk `langchain-core-npm-1.0.0-messages-is-chat-message-chunk-deprecated`	Deprecation	`isChatMessageChunk` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isDataContentBlock `langchain-core-npm-1.0.0-messages-is-data-content-block-deprecated`	Deprecation	`isDataContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isHumanMessage `langchain-core-npm-1.0.0-messages-is-human-message-deprecated`	Deprecation	`isHumanMessage` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isHumanMessageChunk `langchain-core-npm-1.0.0-messages-is-human-message-chunk-deprecated`	Deprecation	`isHumanMessageChunk` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isIDContentBlock `langchain-core-npm-1.0.0-messages-is-idcontent-block-deprecated`	Deprecation	`isIDContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isPlainTextContentBlock `langchain-core-npm-1.0.0-messages-is-plain-text-content-block-deprecated`	Deprecation	`isPlainTextContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isSystemMessage `langchain-core-npm-1.0.0-messages-is-system-message-deprecated`	Deprecation	`isSystemMessage` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isSystemMessageChunk `langchain-core-npm-1.0.0-messages-is-system-message-chunk-deprecated`	Deprecation	`isSystemMessageChunk` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isToolMessage `langchain-core-npm-1.0.0-messages-is-tool-message-deprecated`	Deprecation	`isToolMessage` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isToolMessageChunk `langchain-core-npm-1.0.0-messages-is-tool-message-chunk-deprecated`	Deprecation	`isToolMessageChunk` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated isURLContentBlock `langchain-core-npm-1.0.0-messages-is-urlcontent-block-deprecated`	Deprecation	`isURLContentBlock` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated parseBase64DataUrl `langchain-core-npm-1.0.0-messages-parse-base64-data-url-deprecated`	Deprecation	`parseBase64DataUrl` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Deprecated parseMimeType `langchain-core-npm-1.0.0-messages-parse-mime-type-deprecated`	Deprecation	`parseMimeType` imported from `@langchain/core/messages`	Patch, only when you name a model provider	Your typecheck and tests
Removed secretsFromEnv from the second argument of load() `langchain-core-npm-1.0.0-load-load-argument-2-secrets-from-env-removed`	Breaking	the `secretsFromEnv` key in argument 1 of `load` imported from `@langchain/core/load`	Patch, only when you name a model provider	Your typecheck and tests
Removed maxDepth from the second argument of load() `langchain-core-npm-1.0.0-load-load-argument-2-max-depth-removed`	Breaking	the `maxDepth` key in argument 1 of `load` imported from `@langchain/core/load`	Patch, only when you name a model provider	Your typecheck and tests

emendant explain <change-id> prints any row's entry, guidance and sources at the terminal.

The error TS lines are what TypeScript 5.9.3 printed when code that compiled against @langchain/core 0.3.80 was compiled against 1.0.0. A row without one is a change the compiler does not report, such as a deprecation or a change in behaviour.

Coverage

Requires emendant@0.1.4 or later. Run emendant feed update to get the latest coverage.

Coverage details

Snapshot: 2026-09-20.1, sequence 27, signed 20 September 2026
Feed entry: feed/npm/@langchain/core/1.0.0.json

emendant feed status shows the snapshot your machine holds.

Primary sources

Scan your repository

Find affected code without editing your files.

npx emendant scan

Then npx emendant fix writes the patches the table says exist. The getting started guide covers the flags and the patch grades.

Later @langchain/core release: @langchain/core 1.1.7: CallbackManager and LangChainTracer signatures change with LangSmith 0.4
Upgrade together with: LangChain 1.0 for JavaScript: the legacy modules moved to @langchain/classic

The LangChain.js migration guide lists every release page and says which to read for your upgrade.