Effect-TS/effect effect@4.0.0-beta.102 on GitHub

Patch Changes

#6563 b6392e1 Thanks @tim-smart! - unstable/reactivity Atom: add withEquality combinator for customizing how the registry detects value changes
#6574 7ed9450 Thanks @tim-smart! - unstable/http HttpClientRequest: add updateHeaders and removeHeader combinators for transforming or removing request headers, closes #6271
#6641 45762bd Thanks @tim-smart! - Add manual flushing to the OTLP exporters through a shared Flusher service exposed by each signal layer. The signal layer output types now include Flusher, and OtlpExporter.make requires it so custom exporters register unconditionally.
#6616 a6e8391 Thanks @tim-smart! - Add Tool.setNeedsApproval for replacing the approval policy of an existing tool.
4ac7e8b Thanks @IMax153! - Add Effect.updateServiceScoped for updating a context service until the current scope closes, with customizable reset behavior.
#6593 4cd40f5 Thanks @tim-smart! - Fix Channel.mergeAll to propagate outer failures promptly and interrupt active inner channels.
#6610 6956bc0 Thanks @ebramanti! - Update McpServer.layerHttp to return 405 for unsupported HTTP methods, reject unsupported MCP-Protocol-Version headers with 400, and return an empty 202 for accepted notifications and responses.
#6608 0e50ec7 Thanks @gcanti! - Add Schema.Natural for non-negative safe integers and use canonical Schema.Int, Schema.Finite, and Schema.Natural schemas for numeric domain values across Effect, AI protocols, and OpenAPI patches.
Update the date, date-time, file, time-zone, cluster, event-log, persistence, socket, SQL, and DevTools schemas to reject invalid non-finite or non-integer values where appropriate. Correct the decoded schema of Schema.NumberFromString, and allow Schema.DurationFromMillis and Schema.DurationFromNanos to represent negative durations.
#6599 9fcdade Thanks @tim-smart! - Interrupt in-flight stream pulls when closing an async iterator.
#6638 57367d5 Thanks @tim-smart! - Fix PartitionedSemaphore.take leaking partially acquired permits when interrupted.
#6615 35c445f Thanks @tim-smart! - Expose the tool call ID to AI tool handlers and Toolkit.WithHandler.handle wrappers.
#6561 c917bb9 Thanks @hsubra89! - Reject unexpected positional arguments left after command parsing, including values exceeding Argument.variadic maximum bounds.
#6613 bc1f358 Thanks @tim-smart! - Ignore duplicate chunk indexes when joining event log messages.
#6552 0e0c9d7 Thanks @xianjianlf2! - Fix a race where FiberHandle.clear could remove a newer fiber installed while the previous fiber was still interrupting.
#6598 73d40aa Thanks @tim-smart! - Fix LanguageModel.streamText to apply the configured concurrency limit to tool call resolution, including approval checks.
#6637 4f1e318 Thanks @tim-smart! - Fix Latch open/release resuming waiters that registered after a subsequent close.
Latch.open and Latch.release schedule the waiter flush on the fiber's
dispatcher. Previously the flush drained whatever waiters existed at flush
time, so a waiter that registered after the latch was closed again could be
resumed by the stale flush. The waiters are now snapshotted at schedule time,
so only waiters covered by an open/release call are resumed.
#6614 9d8d85c Thanks @tim-smart! - Fix histogram and summary maximum values for negative-only observations.
#6634 6079fda Thanks @fubhy! - Fix OTLP exporter shutdown to await in-flight and final buffered exports up to the configured shutdown timeout.
#6567 5101e92 Thanks @gcanti! - Add Record.assignProperty and safely handle dynamic record keys such as __proto__ and inherited property names.
#6592 d0b3265 Thanks @tim-smart! - Fix Stream.haltWhen to observe halt effects at pull boundaries for synchronous streams.
#6618 7a03c89 Thanks @tim-smart! - unstable/cluster: hash over-length SQL message deduplication keys to prevent message_id overflow, closes #6317.
The composed request deduplication key (entityType/entityId/tag/primaryKey) can legally exceed the 255-character message_id column — the address columns alone allow 458 characters before the RPC primary key is appended. SqlMessageStorage now stores a SHA-256 digest (64 hex characters) of the composed key in the unique message_id column when the key exceeds 255 characters, so keys of any length work on PostgreSQL, MySQL, MSSQL, and SQLite. Keys that fit are stored as plaintext, byte-compatible with rows written by previous versions, so existing deployments keep deduplicating with no migration or schema change.
SqlMessageStorage.layer/layerWith (and consequently SingleRunner.layer) now require Crypto.Crypto. The Node and Bun cluster convenience layers provide the platform Crypto implementation internally, so their requirements are unchanged.

#6577 cea1d9c Thanks @tim-smart! - ManagedRuntime: add Symbol.asyncDispose, enabling await using syntax

import { Effect, Layer, ManagedRuntime } from "effect";

await using runtime = ManagedRuntime.make(Layer.empty);

await runtime.runPromise(Effect.log("Hello, world!"));
// runtime is disposed automatically at the end of the scope

#6644 078e1f5 Thanks @gcanti! - Improve the performance of Array.dedupe, Array.union, Array.intersection, Array.difference, and Schema unique item validation by using hash-based equality lookup.
#6609 97bafea Thanks @tim-smart! - Allow embedding usage input tokens to be omitted during decoding, including after JSON serialization.
#6606 fab0ab8 Thanks @tim-smart! - Allow optional AI response fields to be omitted during decoding, including after JSON serialization.
#6607 c323d8b Thanks @ebramanti! - Prevent MCP tool failures from exposing Cause rendering, stack traces, and internal paths while preserving actionable validation messages.

#6576 6966353 Thanks @tim-smart! - Record: make fromIterableBy dual, allowing data-last usage in pipe

import { pipe, Record } from "effect";

const users = [
  { id: "2", name: "name2" },
  { id: "1", name: "name1" },
];

pipe(
  users,
  Record.fromIterableBy((user) => user.id),
);

#6622 0444004 Thanks @gcanti! - Remove the experimental SchemaUtils module and its getNativeClassSchema helper. The helper duplicated a composition already available through the primary Schema APIs and did not justify a separate public module.
#6653 028bbb3 Thanks @tim-smart! - Remove Effect.withConcurrency, the References.CurrentConcurrency reference backing it, and the "inherit" option from Types.Concurrency. Use an explicit number or "unbounded" concurrency value instead.
#6620 ff5d6e2 Thanks @gcanti! - Make Schema.Date reject invalid dates and remove the redundant Schema.DateValid, Schema.isDateValid, and Schema.isDateValidReviver APIs.
Schema.DateFromString and Schema.DateFromMillis now fail decoding when their input would produce an invalid date.
Remove Schema.Annotations.ToArbitrary.GenerationConstraint.valid; Schema.Date arbitraries now generate only valid dates by default.
#6575 1bfce93 Thanks @gcanti! - Schema: make schemas directly extendable as classes with static method support
and remove Schema.asClass.
Bottom and BottomLazy now include the class-compatible new signature,
while BottomWithoutNew and BottomLazyWithoutNew expose the schema protocol
without it for schema types that define a specialized construct signature.
Example
```
import { Schema } from "effect";

class MyString extends Schema.String {
  static readonly decodeUnknownSync = Schema.decodeUnknownSync(this);
}

MyString.decodeUnknownSync("a"); // "a"
```
#6424 7ce815c Thanks @gcanti! - Refactor the SchemaRepresentation module to improve clarity and maintainability.
The representation pipeline is now open and compiler-extensible. The same encoded-side representation is used for JSON persistence, runtime reconstruction, JSON Schema Draft 2020-12 compilation, TypeScript code generation, AI structured output, and HTTP / OpenAPI schemas.
New representation model
- Add RepresentationAnnotation and CheckRepresentationAnnotation, which identify declarations and checks with a stable id, JSON payload, and optional schema dependencies.
- Preserve checks on every non-reference representation node instead of storing constraints in the previous closed meta unions.
- Add compiler hooks for checks and declarations through SchemaRepresentation.ToJsonSchema and SchemaRepresentation.Generation.
- Add SchemaMultiDocument, fromSchemaMultiDocument, and fromRepresentations so several live schemas and named definitions can be converted and reconstructed together. Explicit definitions are preserved even when no root references them.
- Preserve shared structural nodes, annotated recursion, union member order, identifiers, reference siblings, and structural checks when projecting encoded schemas.
Persistence and revivers
- Add toJson, fromJson, toJsonMultiDocument, and fromJsonMultiDocument as the persistence boundary for representation documents.
- Live representations store literal, enum, and property-name scalars as native values. JSON persistence encodes them as { type, value } tagged unions so their runtime types remain distinct across persistence formats, canonically encodes structural bigint and global symbol values, keeps JSON-valued annotations, and removes runtime-only callbacks and other non-JSON annotation values.
- Replace the generic reviver callback with typed DeclarationReviver, FilterReviver, and FilterGroupReviver contracts. Add makeDeclarationReviver, makeFilterReviver, and makeFilterGroupReviver, which infer their payload type from payloadSchema.
- Resolve acyclic references to concrete runtime schemas and reserve Schema.suspend wrappers for recursive back-edges. Acyclic alias chains may be normalized while preserving the outer reference identifier.
- Export individual revivers for built-in declarations and checks from Schema. Consumers opt in to exactly the revivers accepted when reconstructing persisted documents:
 - declaration revivers: OptionReviver, ResultReviver, RedactedReviver, CauseReasonReviver, CauseReviver, ErrorReviver, ExitReviver, ReadonlyMapReviver, HashMapReviver, ReadonlySetReviver, HashSetReviver, ChunkReviver, RegExpReviver, URLReviver, DateReviver, DurationReviver, BigDecimalReviver, FileReviver, FormDataReviver, URLSearchParamsReviver, Uint8ArrayReviver, DateTimeUtcReviver, TimeZoneOffsetReviver, TimeZoneNamedReviver, TimeZoneReviver, DateTimeZonedReviver, JsonReviver, and MutableJsonReviver
 - check revivers: isTrimmedReviver, isPatternReviver, isStringFiniteReviver, isStringBigIntReviver, isStringSymbolReviver, isUUIDReviver, isGUIDReviver, isULIDReviver, isBase64Reviver, isBase64UrlReviver, isStartsWithReviver, isEndsWithReviver, isIncludesReviver, isUppercasedReviver, isLowercasedReviver, isCapitalizedReviver, isUncapitalizedReviver, isFiniteReviver, isGreaterThanReviver, isGreaterThanOrEqualToReviver, isLessThanReviver, isLessThanOrEqualToReviver, isBetweenReviver, isMultipleOfReviver, isIntReviver, isDateValidReviver, isGreaterThanDateReviver, isGreaterThanOrEqualToDateReviver, isLessThanDateReviver, isLessThanOrEqualToDateReviver, isBetweenDateReviver, isGreaterThanBigIntReviver, isGreaterThanOrEqualToBigIntReviver, isLessThanBigIntReviver, isLessThanOrEqualToBigIntReviver, isBetweenBigIntReviver, isMinLengthReviver, isMaxLengthReviver, isLengthBetweenReviver, isMinSizeReviver, isMaxSizeReviver, isSizeBetweenReviver, isMinPropertiesReviver, isMaxPropertiesReviver, isPropertiesLengthBetweenReviver, isPropertyNamesReviver, and isUniqueReviver
- Validate reviver payloads with their payloadSchema, and report missing or duplicate reviver identifiers.
JSON Schema and code generation
- Compile JSON Schema from the canonical JSON codec and the encoded-side representation. Custom checks can contribute constraints through Annotations.Filter.toJsonSchema without modifying a central metadata registry.
- Import JSON Schema directly as live schemas. The importer now supports shared definitions, aliases, recursion, reference siblings, and definitions that are not reachable from a root.
- Add the named FromJsonSchemaOptions type for the importer onEnter callback.
- Generate code from live toCode annotations on declarations and checks. Compiler callbacks receive generated type parameters or schema dependencies and can emit multiple import declarations.
- Add import artifacts to CodeDocument and preserve all explicit definitions during multi-document code generation.
- Reject distinct schemas that declare the same identifier instead of silently merging them or generating suffixed references.
Canonical codecs and integrations
- Preserve schema identifiers, property context, key encodings, and applicable checks while deriving canonical JSON codecs.
- Treat Schema.Json and Schema.MutableJson as already canonical. JSON validation now rejects sparse arrays, and non-finite numbers decode only from the canonical strings "Infinity", "-Infinity", and "NaN" rather than raw non-finite numeric inputs.
- Declarations without toCodecJson or toCodec now use JSON validation as their fallback instead of silently encoding to null. toCodecJson callbacks may return undefined when a declaration is already canonical.
- Add Annotations.Declaration.toCodecStringTree; StringTree derivation now requires a declaration to provide a structural StringTree, JSON, or general codec instead of silently encoding an opaque declaration to undefined.
- Update AI structured-output, HTTP schema, HttpApi OpenAPI, and OpenAPI generator integrations to consume the same canonical encoded representation and compiler hooks. Provider-specific structured-output transforms may remove unsupported JSON Schema keywords, while the Effect codec remains the validation authority.
Breaking changes
- Rename the low-level representation constructors:
 - SchemaRepresentation.fromAST -> SchemaRepresentation.toRepresentation
 - SchemaRepresentation.fromASTs -> SchemaRepresentation.toRepresentations
- Replace SchemaRepresentation.toSchema with fromRepresentation, and add fromRepresentations for multi-root documents. Both reconstruction functions require { revivers: [...] }; no default reviver is installed implicitly.
- Remove SchemaRepresentation.toSchemaDefaultReviver. Pass the required built-in revivers exported by Schema, or custom revivers created with the new constructors.
- Replace DocumentFromJson and MultiDocumentFromJson with the toJson / fromJson and toJsonMultiDocument / fromJsonMultiDocument functions.
- The persisted Document and MultiDocument format is incompatible with the previous format. Nodes now contain checks; encoded literal values, enum values, and property signature names use tagged { type, value } objects while decoded documents expose their native scalar values; declarations no longer contain encodedSchema; persisted opaque declarations and leaf filters require a { id, payload } representation identity; and checks no longer contain closed meta payloads. Regenerate stored documents from their source schemas with the new API, or migrate their shape before passing them to fromJson.
- Replace the generic Reviver<T> function type with DeclarationReviver, FilterReviver, FilterGroupReviver, CheckReviver, Reviver, and AnyReviver.
- Remove the closed metadata types StringMeta, NumberMeta, BigIntMeta, ArraysMeta, ObjectsMeta, DateMeta, SizeMeta, DeclarationMeta, and Meta from SchemaRepresentation.
- Remove the exported representation validation schemas and PrimitiveTree: $PrimitiveTree, $Annotations, $Null, $Undefined, $Void, $Never, $Unknown, $Any, $StringMeta, $String, $NumberMeta, $Number, $Boolean, $BigInt, $Symbol, $LiteralValue, $Literal, $UniqueSymbol, $ObjectKeyword, $Enum, $TemplateLiteral, $Element, $Arrays, $PropertySignature, $IndexSignature, $ObjectsMeta, $Objects, $Union, $Reference, $DateMeta, $SizeMeta, $DeclarationMeta, $Declaration, $Suspend, $Representation, $Document, and $MultiDocument.
- Replace schema annotations as follows:
 - remove Annotations.Bottom.meta and Annotations.Filter.meta
 - remove Annotations.Declaration.typeConstructor; use representation
 - remove Annotations.Declaration.generation; use the toCode callback
 - add Annotations.Filter.representation, toJsonSchema, and toCode
 - add Annotations.Augment.contentSchema as a JSON-valued annotation
 - allow Annotations.Declaration.toCodecJson and toCodecStringTree to return undefined
- Remove the top-level contentMediaType and contentSchema fields from SchemaRepresentation.String. Content metadata is now carried in ordinary annotations, and contentSchema is a JSON Schema value rather than a nested Effect representation.
- Remove Schema.Annotations.BuiltInMetaDefinitions, BuiltInMeta, MetaDefinitions, and Meta. Custom checks should carry a representation identity and compiler callbacks instead of augmenting the metadata registry.
- fromJsonSchemaDocument now returns Schema.Top instead of a representation Document. fromJsonSchemaMultiDocument now returns SchemaMultiDocument instead of MultiDocument; call fromSchemaMultiDocument when a representation multi-document is required.
- toCodeDocument now accepts only a live MultiDocument; remove its reviver option. Reconstruct persisted documents first so revivers can restore runtime compiler callbacks.
- Rename the generation field of Artifact values for symbols and enums to code. Declaration generation no longer has an Encoded output, and importDeclaration is replaced by importDeclarations on callback output.
- Remove the exported sanitizeJavaScriptIdentifier, topologicalSort, and TopologicalSort helpers.
- Negative zero no longer receives special representation handling. Do not rely on preserving its sign across JSON persistence or generated code, where it may be normalized to 0.
- With { errors: "all" }, structural checks run only after their base array, object, or declaration parses successfully; they are no longer added to an already failing child parse.
#6646 7271a7f Thanks @gcanti! - Precompile union formatters and equivalences, select transformed union members using their decoded type, and allow deriving an equivalence for Never.
#6516 475fe5c Thanks @tim-smart! - Prevent SQL runner lock refreshes from hanging when reserved connections become unresponsive.

Effect-TS/effect effect@4.0.0-beta.102 on GitHub

Patch Changes

New representation model

Persistence and revivers

JSON Schema and code generation

Canonical codecs and integrations

Breaking changes

Effect-TS/effect effect@4.0.0-beta.102
on GitHub