test(java): add arity 0 and arity 2 coverage to ErgonomicToolDefinitionIT

[edburns]

Both the annotation-based (ErgonomicTestTools) and lambda-based (ToolDefinition.from()) APIs previously only exercised arity 1.

This commit adds:

• ErgonomicTestTools.getStatus() — zero-parameter @copilotTool
• ErgonomicTestTools.combineValues(String, String) — two-parameter @copilotTool
• ergonomicToolArity0 / lambdaToolArity0 test methods (Supplier overload)
• ergonomicToolArity2 / lambdaToolArity2 test methods (BiFunction overload)
• test/snapshots/tools/ergonomic_tool_arity0.yaml
• test/snapshots/tools/ergonomic_tool_arity2.yaml

[Copilot]

Pull request overview

Extends the Java E2E integration coverage for tool-definition ergonomics by exercising arity 0 and arity 2 tool handlers for both the annotation-based (@CopilotTool + ToolDefinition.fromObject) and lambda-based (ToolDefinition.from(...)) APIs, using replay-proxy snapshots under test/snapshots/tools/.

Changes:

• Added new zero-arg and two-arg E2E test cases in ErgonomicToolDefinitionIT for both annotation-based and lambda-based tool definitions.
• Added two new tool fixture methods (getStatus, combineValues) to ErgonomicTestTools to cover arity 0 and 2 for the annotation-based path.
• Added new replay snapshots for the new arity scenarios.

Show a summary per file

File	Description
java/src/test/java/com/github/copilot/e2e/ErgonomicToolDefinitionIT.java	Adds arity 0 and arity 2 E2E coverage for both annotation-based and lambda-based tool definitions.
java/src/test/java/com/github/copilot/e2e/ErgonomicTestTools.java	Adds @CopilotTool methods to exercise zero-parameter and two-parameter annotation-based tools.
test/snapshots/tools/ergonomic_tool_arity0.yaml	New replay snapshot for the arity-0 tool invocation flow (get_status).
test/snapshots/tools/ergonomic_tool_arity2.yaml	New replay snapshot for the arity-2 tool invocation flow (combine_values).

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 0
• Review effort level: Low

[github-actions]

Cross-SDK Consistency Review ✅

This PR adds arity 0 and arity 2 test coverage to the Java ErgonomicToolDefinitionIT — all changes are test-only (Java E2E test files + two new shared replay snapshots).

No cross-SDK consistency issues found. Here's why:

Java-specific APIs being tested

The @CopilotTool annotation ergonomic API and the overloaded ToolDefinition.from() variants (Supplier for arity 0, BiFunction for arity 2) are Java-idiomatic features. Equivalent "arity" concepts don't apply to the other SDKs in the same way:

SDK	Arity handling
Java	Explicit overloads: from(Supplier), from(Param, Function), from(Param, Param, BiFunction)
Python	Function introspection at decoration time — 0-param, 1-param, and 2-param all resolved via inspect.signature
Go	Struct-based params in DefineTool[T, U] — arity emerges from struct fields, no explicit overloads needed
.NET	Delegate + reflection via AIFunctionFactory.Create — any arity is handled uniformly

Snapshots

The two new YAML snapshots (ergonomic_tool_arity0.yaml, ergonomic_tool_arity2.yaml) follow the existing snapshot conventions correctly and are usable by any SDK test that exercises zero- or two-param tools against the replay proxy.

No action needed in other SDK implementations.

Generated by SDK Consistency Review Agent for issue #1897 · sonnet46 1.2M · ◷