php-sdk/CHANGELOG.md
Antoine Bluchet df5379c047
[Server] Harden JSON-RPC input parsing against malformed input and resource exhaustion (#383)
* fix: harden JSON-RPC input parsing against malformed input and DoS

MessageFactory::create() detected batches via $input[0] === '{', which
mishandled valid-but-non-object JSON: a scalar ("5") or leading-whitespace
object silently returned [] (with a PHP warning) or could reach a foreach
over a non-array. It also had no bound on batch size, letting one small
request expand into arbitrarily many operations (amplification).

- Detect single-vs-batch from the decoded JSON type (object vs list array)
  instead of the raw first byte; reject scalars and empty payloads as
  InvalidInputMessageException rather than crashing or no-oping.
- Cap batch size (maxBatchSize, default 100) and reject oversized batches.
- Reject non-object batch elements as InvalidInputMessageException instead
  of letting them hit a TypeError.
- Bound the StreamableHttpTransport POST body (maxBodyBytes, default 4 MiB),
  returning 413, with an incremental read so unknown-size/chunked bodies
  cannot exhaust memory.

* docs: document input-hardening limits in CHANGELOG and transports guide

Add CHANGELOG entries and docs/transports.md sections for the JSON-RPC
batch size cap (maxBatchSize) and the StreamableHttpTransport request
body size cap (maxBodyBytes), plus the type-based single-vs-batch
message detection.
2026-07-06 00:10:13 +02:00

8.6 KiB

Changelog

All notable changes to mcp/sdk will be documented in this file.

0.6.0

  • Add Builder::add(Tool|ResourceDefinition|ResourceTemplate|Prompt $definition, ElementHandlerInterface $handler) for explicit registration of elements whose schema is only known at runtime.
  • Add handler interfaces ToolHandlerInterface, ResourceHandlerInterface, ResourceTemplateHandlerInterface, PromptHandlerInterface, and the ElementHandlerInterface marker.
  • [BC Break] Renamed Mcp\Schema\Resource to Mcp\Schema\ResourceDefinition. No alias.
  • [BC Break] Renamed Mcp\Capability\Registry\Loader\ArrayLoader to Mcp\Capability\Registry\Loader\ReflectedElementLoader.
  • [BC Break] Bump default protocol version to 2025-11-25
  • Add support for MCP Apps extension in schema and server
  • Add extensions to ServerCapabilities and ClientCapabilities and Builder::enableExtension()
  • Allow overriding the default name pattern for Discovery
  • Add configurable session garbage collection (gcProbability/gcDivisor)
  • Add optional title field to ResourceDefinition and ResourceTemplate for MCP spec compliance
  • Add ChainLoader to compose multiple LoaderInterface implementations via explicit ordering.
  • Add RegistryInterface::unregisterTool(), unregisterResource(), unregisterResourceTemplate(), unregisterPrompt() — idempotent removals.
  • Add RegistryInterface::hasTool(), hasResource(), hasResourceTemplate(), hasPrompt() — by-name existence checks.
  • DiscoveryLoader now refreshes only its own previously written entries; manual registrations (via Builder::addTool() etc. or runtime $registry->registerTool() calls) survive rediscovery, and a same-name manual registration takes precedence over discovery on collision.
  • [BC Break] Removed ElementReference::$isManual public property and the bool $isManual parameter from all *Reference constructors. Origin tracking is no longer carried on the element; manual-over-discovered precedence is encoded by loader execution order.
  • [BC Break] RegistryInterface::registerTool(), registerResource(), registerResourceTemplate(), registerPrompt() lost their trailing bool $isManual = false parameter. Callers using positional arguments must drop the flag.
  • [BC Break] Removed RegistryInterface::clear(), getDiscoveryState(), setDiscoveryState(). Rediscovery now goes through DiscoveryLoader::load() directly.
  • Registry::register*() semantics changed to plain last-write-wins (overwrites silently) and the methods now return the stored *Reference. The previous "discovered registration is ignored when a manual one already exists" precedence rule still applies, but is now enforced by DiscoveryLoader via reference-identity tracking — and still emits a debug log when a discovery is skipped due to a conflicting registration.
  • Add optional title parameter to Builder::addResource() and Builder::addResourceTemplate() for MCP spec compliance
  • [BC Break] Builder::addResource() signature changed — $title parameter added between $name and $description. Callers using positional arguments must switch to named arguments.
  • [BC Break] Builder::addResourceTemplate() signature changed — $title parameter added between $name and $description. Callers using positional arguments must switch to named arguments.
  • Add CorsMiddleware, DnsRebindingProtectionMiddleware, and ProtocolVersionMiddleware for StreamableHttpTransport, composed automatically as the default stack via StreamableHttpTransport::defaultMiddleware()
  • [BC BREAK] StreamableHttpTransport constructor: $corsHeaders parameter removed; CORS is now configured via CorsMiddleware. The $middleware parameter is nullable — null (or omitted) installs the default stack; [] disables all defaults. Default Access-Control-Allow-Origin is no longer set (was *).
  • [BC Break] ResourceDefinition::__construct() signature changed — $title parameter added between $name and $description. Callers using positional arguments must switch to named arguments.
  • [BC Break] ResourceTemplate::__construct() signature changed — $title parameter added between $name and $description. Callers using positional arguments must switch to named arguments.
  • [BC Break] McpResource and McpResourceTemplate attribute signatures changed — $title parameter added between $name and $description. Callers using positional arguments must switch to named arguments.
  • Harden JSON-RPC input parsing: single-message vs batch is now decided from the decoded JSON type (object → single, list array → batch) instead of the raw first byte. Scalars, empty payloads, and non-object batch elements are surfaced as InvalidInputMessageException entries instead of triggering warnings or a TypeError.
  • Add maxBatchSize (default 100) to MessageFactory — oversized JSON-RPC batches are rejected before any message is constructed, guarding against amplification.
  • Add maxBodyBytes (default 4 MiB) to StreamableHttpTransport — POST bodies exceeding the cap are rejected with 413. Unknown-size/chunked bodies are read incrementally and stopped at the cap so they cannot exhaust memory.

0.5.0

  • Add built-in authentication middleware for HTTP transport using OAuth
  • Add client component for building MCP clients
  • Add Builder::setReferenceHandler() to allow custom ReferenceHandlerInterface implementations (e.g. authorization decorators)
  • Add elicitation enum schema types per SEP-1330: TitledEnumSchemaDefinition, MultiSelectEnumSchemaDefinition, TitledMultiSelectEnumSchemaDefinition
  • [BC break] Make Symfony Finder component optional. Users would need to install symfony/finder now themselves
  • Add LenientOidcDiscoveryMetadataPolicy for identity providers that omit code_challenge_methods_supported (e.g. FusionAuth, Microsoft Entra ID)
  • Add OAuth 2.0 Dynamic Client Registration middleware (RFC 7591)
  • Add optional title field to Prompt and McpPrompt for MCP spec compliance
  • [BC Break] Builder::addPrompt() signature changed — $title parameter added between $name and $description. Callers using positional arguments for $description must switch to named arguments.
  • Add optional title field to Tool and McpTool for MCP spec compliance
  • [BC Break] Tool::__construct() signature changed — $title parameter added between $name and $inputSchema. Callers using positional arguments must switch to named arguments or pass null for $title.
  • [BC Break] McpTool attribute signature changed — $title parameter added between $name and $description. Callers using positional arguments for $description must switch to named arguments.
  • [BC Break] Builder::addTool() signature changed — $title parameter added between $name and $description. Callers using positional arguments for $description must switch to named arguments.

0.4.0

  • Rename Mcp\Server\Session\Psr16StoreSession to Mcp\Server\Session\Psr16SessionStore
  • Add missing handlers for resource subscribe/unsubscribe and persist subscriptions via session
  • Introduce SessionManager to encapsulate session handling (replaces SessionFactory) and move garbage collection logic from Protocol.

0.3.0

  • Add output schema support to MCP tools
  • Add validation of the input parameters given to a Tool.
  • Rename Mcp\Capability\Registry\ResourceReference::$schema to Mcp\Capability\Registry\ResourceReference::$resource.
  • Introduce SchemaGeneratorInterface and DiscovererInterface to allow custom schema generation and discovery implementations.
  • Remove DocBlockParser::getSummary() method, use DocBlockParser::getDescription() instead.

0.2.2

  • Throw exception when trying to inject parameter with the unsupported names $_session or $_request.
  • Throwable objects are passed to log context instead of the exception message.

0.2.1

  • Add RunnerControl for StdioTransport to allow break out from continuously listening for new input.
  • Open range of supported Symfony versions to include v5.4

0.2.0

  • Make Protocol stateless by decouple if from TransportInterface. Removed Protocol::getTransport().
  • Change signature of Builder::addLoaders(...$loaders) to Builder::addLoaders(iterable $loaders).
  • Removed ClientAwareInterface in favor of injecting a RequestContext with argument injection.
  • The ClientGateway cannot be injected with argument injection anymore. Use RequestContext instead.
  • Removed ClientAwareTrait
  • Removed Protocol::getTransport()
  • Added parameter for TransportInterface to Protocol::processInput()

0.1.0

  • First tagged release of package
  • Support for implementing MCP server