java-sdk/conformance-tests/client-spring-http-client
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Filename Latest commit message Latest commit date
Dariusz Jędrzejczyk 22a0efa577 feat!: enforce required MCP spec fields in McpSchema; lenient wire deserialization (#928)
Every wire-serialized record in McpSchema now validates spec-required
fields at construction time. Wire deserialization is intentionally
lenient: a missing required field is replaced with a documented default
and a WARN is logged, instead of failing the parse. A required-first
builder convention is introduced across the schema so it is no longer
possible to obtain a builder that is missing required state.

Required-field guards
---------------------
Every wire record's compact constructor asserts non-null (and non-empty
for String identifiers like name, uri, uriTemplate, version) on its
spec-required components. Passing null now throws
IllegalArgumentException at construction time instead of silently
producing invalid JSON via @JsonInclude(NON_ABSENT). This applies to
the JSON-RPC envelopes, lifecycle types, resource/prompt/tool requests
and results, sampling and elicitation, content records, root, complete,
logging and progress notifications, and the two CompleteReference
implementations. See MIGRATION-2.0.md for the full list.

Lenient wire deserialization
----------------------------
For each of those records (except JSONRPCResponse.JSONRPCError, which
still fails fast) a @JsonCreator static `fromJson` factory substitutes
a documented default for any absent required field — "" for strings,
[] for collections, {} for maps, 0 / 0.0 for numerics, INFO for
LoggingLevel, USER for SamplingMessage.role, ASSISTANT for
CreateMessageResult.role, CANCEL for ElicitResult.action, {values=[]}
for CompleteResult.completion — and logs a WARN naming the field and
the value used. Application code can still observe a malformed message
and react, but the SDK no longer halts the conversation.

Builder convention
------------------
Records that have a builder gain a required-first factory method
`builder(req1, req2, …)`; setters for required fields are removed from
the builder so it cannot be left in an invalid state. Existing no-arg
`builder()` factories and required-field setters are kept where source
compatibility demands it but are marked @Deprecated. New builders are
also added for several records that previously had none (ProgressNotification,
JSONRPCError, CompleteRequest, list/result types, content records, ...).

JSON-RPC envelope ergonomics
----------------------------
Previously every JSON-RPC envelope had to be constructed via the
canonical record constructor and the literal "2.0" string had to be
threaded through every call site, e.g.

    new JSONRPCRequest("2.0", "tools/call", id, params)
    new JSONRPCResponse("2.0", id, result, null)
    new JSONRPCResponse("2.0", id, null, new JSONRPCError(code, message, null))

Now:

    new JSONRPCRequest("tools/call", id, params)              // jsonrpc defaulted
    new JSONRPCNotification("notifications/initialized")       // params optional
    JSONRPCResponse.result(id, result)                        // factory
    JSONRPCResponse.error(id, new JSONRPCError(code, message)) // 2-arg error

JSONRPCResponse's compact constructor additionally enforces the
JSON-RPC invariant that exactly one of `result` / `error` is set —
previously the SDK could build envelopes that violated the protocol.

CompleteReference changes
-------------------------
- PromptReference.equals/hashCode now key on `name` only (previously
  derived from identifier()+type()). Two refs with the same name but
  different titles now compare equal — code using PromptReference as a
  map/set key should be audited.
- PromptReference's compact constructor pins `type` to "ref/prompt"
  and logs a WARN if the caller supplies a different non-null value.
  The legacy two-arg `PromptReference(String type, String name)`
  constructor remains @Deprecated.
- ResourceReference's record components are reduced from (type, uri)
  to (uri) — positional construction breaks. The legacy
  `ResourceReference(String type, String uri)` constructor stays
  @Deprecated and ignores `type`.
- CompleteReference.identifier() is @Deprecated and now returns null
  via a default method on the interface.

Tests / refactor
----------------
Conformance harness, integration tests, sample apps, and internal
callers were migrated to the new builder factories and convenience
constructors. No semantic changes to client/server runtime behaviour
beyond the McpSchema changes above.

Docs
----
- MIGRATION-2.0.md: required-field section now covers the broader
  record set and the lenient-deserialization behaviour; PromptReference
  WARN behaviour and ResourceReference component reduction are
  documented; the JSON-RPC envelope section is rewritten to compare the
  pre-2.0 surface with the new one.
- CONTRIBUTING.md: the "Evolving wire-serialized records" recipe is
  split into two cases — adding a new optional field (existing rules)
  and adding/maintaining a spec-required field (new rules covering
  Assert in compact constructor, @JsonCreator fromJson with defaults
  and WARN, required-first builder factory).

Signed-off-by: Dariusz Jędrzejczyk <2554306+chemicL@users.noreply.github.com>
2026-05-04 21:01:46 +02:00
..
src/main feat!: enforce required MCP spec fields in McpSchema; lenient wire deserialization (#928) 2026-05-04 21:01:46 +02:00
pom.xml conformance: update to mcp-security 0.1.5, pass scope-step-up 2026-04-02 10:55:43 +02:00
README.md conformance: update to mcp-security 0.1.5, pass scope-step-up 2026-04-02 10:55:43 +02:00

MCP Conformance Tests - Spring HTTP Client (Auth Suite)

This module provides a conformance test client implementation for the Java MCP SDK's auth suite.

OAuth2 support is not implemented in the SDK itself, but we provide hooks to implement the Authorization section of the specification. One such implementation is done in Spring, with Sprign AI and the mcp-client-security library.

This is a Spring web application, we interact with it through a normal HTTP-client that follows redirects and performs OAuth2 authorization flows.

Overview

The conformance test client is designed to work with the MCP Conformance Test Framework. It validates that the Java MCP SDK client, combined with Spring Security's OAuth2 support, properly implements the MCP authorization specification.

Test with @modelcontextprotocol/conformance@0.1.15.

Conformance Test Results

Status: 178 passed, 1 failed, 1 warning across 14 scenarios

Scenario Result Details
auth/metadata-default ✅ Pass 12/12
auth/metadata-var1 ✅ Pass 12/12
auth/metadata-var2 ✅ Pass 12/12
auth/metadata-var3 ✅ Pass 12/12
auth/basic-cimd ⚠️ Warning 12/12 passed, 1 warning
auth/scope-from-www-authenticate ✅ Pass 13/13
auth/scope-from-scopes-supported ✅ Pass 13/13
auth/scope-omitted-when-undefined ✅ Pass 13/13
auth/scope-step-up ✅ Pass 12/12
auth/scope-retry-limit ✅ Pass 11/11
auth/token-endpoint-auth-basic ✅ Pass 17/17
auth/token-endpoint-auth-post ✅ Pass 17/17
auth/token-endpoint-auth-none ✅ Pass 17/17
auth/pre-registration ✅ Pass 6/6

See VALIDATION_RESULTS.md for the full project validation results.

Architecture

The client is a Spring Boot application that reads test scenarios from environment variables and accepts the server URL as a command-line argument, following the conformance framework's conventions:

  • MCP_CONFORMANCE_SCENARIO: Environment variable specifying which test scenario to run
  • MCP_CONFORMANCE_CONTEXT: Environment variable with JSON context (used by auth/pre-registration)
  • Server URL: Passed as the last command-line argument

Scenario Routing

The application uses Spring's conditional configuration to select the appropriate scenario at startup:

  • DefaultConfiguration — Activated for all scenarios except auth/pre-registration. Uses the OAuth2 Authorization Code flow with dynamic client registration via McpClientOAuth2Configurer.
  • PreRegistrationConfiguration — Activated only for auth/pre-registration. Uses the Client Credentials flow with pre-registered client credentials read from MCP_CONFORMANCE_CONTEXT.

Key Dependencies

  • Spring Boot 4.0 with Spring Security OAuth2 Client
  • Spring AI MCP Client (spring-ai-starter-mcp-client)
  • mcp-client-security — Community library providing MCP-specific OAuth2 integration (metadata discovery, dynamic client registration, transport context)

Building

Build the executable JAR:

cd conformance-tests/client-spring-http-client
../../mvnw clean package -DskipTests

This creates an executable JAR at:

target/client-spring-http-client-2.0.0-SNAPSHOT.jar

Running Tests

Using the Conformance Framework

Run the full auth suite:

npx @modelcontextprotocol/conformance@0.1.15 client \
  --spec-version 2025-11-25 \
  --command "java -jar conformance-tests/client-spring-http-client/target/client-spring-http-client-2.0.0-SNAPSHOT.jar" \
  --suite auth

Run a single scenario:

npx @modelcontextprotocol/conformance@0.1.15 client \
  --spec-version 2025-11-25 \
  --command "java -jar conformance-tests/client-spring-http-client/target/client-spring-http-client-2.0.0-SNAPSHOT.jar" \
  --scenario auth/metadata-default

Run with verbose output:

npx @modelcontextprotocol/conformance@0.1.15 client \
  --spec-version 2025-11-25 \
  --command "java -jar conformance-tests/client-spring-http-client/target/client-spring-http-client-2.0.0-SNAPSHOT.jar" \
  --scenario auth/metadata-default \
  --verbose

Manual Testing

You can also run the client manually if you have a test server:

export MCP_CONFORMANCE_SCENARIO=auth/metadata-default
java -jar conformance-tests/client-spring-http-client/target/client-spring-http-client-2.0.0-SNAPSHOT.jar http://localhost:3000/mcp

Known Issues

  1. auth/scope-step-up (1 failure) — The client does not fully handle scope step-up challenges where the server requests additional scopes after initial authorization.
  2. auth/basic-cimd (1 warning) — Minor conformance warning in the basic Client-Initiated Metadata Discovery flow.

References