Xcode 26.3 MCP xcode-tools: RunSomeTests / RunAllTests response violates tool output schema (missing required errors per test)

Xcode 26.3 MCP xcode-tools: RunSomeTests / RunAllTests response violates tool output schema (missing required errors per test)

I’m using the MCP server “xcode-tools” shipped with Xcode 26.3 to run tests.

Two tools fail consistently due to a schema mismatch:

• RunSomeTests
• RunAllTests

Steps

1. Call XcodeListWindows and get a valid tabIdentifier for my workspace.
2. Call GetTestList with that tabIdentifier. This works and returns test identifiers like:
   ChatKitManagerCreationTests/testInitializesWithDependencies()
3. Call RunSomeTests with tests = [{ targetName, testIdentifier }, …] (or call RunAllTests).

Actual result

The tool call fails with an MCP schema validation error like:

Structured content does not match the tool's output schema: data/results/0 must have required property 'errors', data/results/1 must have required property 'errors', ...

Why this looks like an xcode-tools bug

According to the tool descriptor JSON for RunSomeTests / RunAllTests, each element of results[] is required to contain:

• targetName
• identifier
• displayName
• state
• errors (required, array of strings)

But the actual response returned by RunSomeTests / RunAllTests appears to omit the errors field for one or more results (for passed tests it should still be present as an empty array []).

Expected result

RunSomeTests / RunAllTests always return structured content matching their declared output schema.
In particular, every results[i] should include errors: [] when there are no errors.

Environment

• Xcode: 26.3
• macOS: Darwin 25.4.0
• Workspace: Grocery.xcworkspace
• Scheme: GroceryCoreTests
• Active test plan: GroceryCoreTests

Question

Is this a known issue in Xcode 26.3’s MCP xcode-tools?
Is there a workaround (e.g. alternative output mode, or reading a full summary file) until the schema/response is fixed?