Added changes to set McpServerOptions.Instructions in HTTPS/SSE mode.

[anushakolan]

Why make this change?

Closes #3283

runtime.mcp.description was configured, but MCP HTTP/SSE initialize did not return it as instructions. This made the engine behavior inconsistent with expected MCP initialization output.

Related discussion: #3282

What is this change?

• Wired runtime MCP description into MCP server options for HTTP/SSE initialization:

  • runtime.mcp.description -> ServerInstructions
  • Files updated:
    • src/Azure.DataApiBuilder.Mcp/Core/McpServiceCollectionExtensions.cs
    • src/Azure.DataApiBuilder.Mcp/Core/McpServerConfiguration.cs

• Added/updated regression coverage for initialize response instructions:

  • src/Service.Tests/Configuration/ConfigurationTests.cs
  • Test: TestMcpInitializeIncludesInstructionsFromRuntimeDescription

How the bug was simulated:

• Reverted the MCP wiring changes and called MCP initialize; result.instructions was missing.

How it was verified after fix:

• Re-applied the wiring, called MCP initialize again, and confirmed result.instructions is present.

How was this tested?

• Integration Tests
• Unit Tests

Ran:

• dotnet test src/Service.Tests/Azure.DataApiBuilder.Service.Tests.csproj --filter "FullyQualifiedName~ConfigurationTests.TestMcpInitializeIncludesInstructionsFromRuntimeDescription" -v minimal

Sample Request(s)

MCP initialize request (HTTP):

curl -i -X POST http://localhost:5000/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc":"2.0",
    "id":1,
    "method":"initialize",
    "params":{
      "protocolVersion":"2025-03-26",
      "capabilities":{},
      "clientInfo":{"name":"manual-test","version":"1.0.0"}
    }
  }'

Expected response snippet after fix:

{
  "result": {
    "instructions": "Use SQL tools to query the database."
  }
}

[Copilot]

Pull request overview

This PR aligns MCP HTTP/SSE initialization behavior with the stdio transport by propagating runtime.mcp.description into the MCP initialize response’s instructions field, and adds a regression test to prevent regressions.

Changes:

• Pass runtime.mcp.description into MCP server configuration during DI setup.
• Set MCP server options (ServerInstructions) so HTTP/SSE initialize includes instructions.
• Add an MSSQL integration test that calls MCP initialize and asserts result.instructions is present (with helper logic to parse JSON vs SSE responses).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
src/Azure.DataApiBuilder.Mcp/Core/McpServiceCollectionExtensions.cs	Passes runtime MCP description into MCP server configuration during service registration.
src/Azure.DataApiBuilder.Mcp/Core/McpServerConfiguration.cs	Adds an instructions parameter and wires it to MCP server options used by HTTP/SSE initialize.
src/Service.Tests/Configuration/ConfigurationTests.cs	Adds a regression test + helper to invoke MCP initialize and validate returned instructions.

[Aniruddh25]

minimize test duplication.