Added missing stored procedure parameters in describe_entities response.

[anushakolan]

Why make this change?

Closes #3400.

describe_entities could return stored procedure entities with empty or partial parameters metadata when parameters were not fully listed in config. This caused MCP clients/agents to miss required inputs and fail execute_entity calls.

Additional discussion: #3400 issue thread.

What is this change?

• Updated DescribeEntitiesTool to include stored procedure parameters from runtime DB metadata.
• Merged DB metadata with config metadata so config values override matching fields (required, default, description).
• Preserved fallback behavior: if metadata resolution fails, config-defined parameters are still returned.
• Added focused MCP tests for:
  • metadata-only parameter discovery
  • config-overrides-DB merge behavior

How was this tested?

• Integration Tests
• Unit Tests

Ran:

• dotnet test src/Service.Tests/Azure.DataApiBuilder.Service.Tests.csproj --filter "FullyQualifiedName~DescribeEntitiesStoredProcedureParametersTests"

Sample Request(s)

MCP request example:

• describe_entities with full metadata:

  • {"name":"describe_entities","arguments":{}}

• execute_entity using discovered parameters:

  • {"name":"execute_entity","arguments":{"entity":"GetBook","parameters":{"id":1}}}

[Copilot]

Pull request overview

Updates MCP describe_entities to reliably include complete stored procedure parameter metadata by augmenting/merging config-defined parameters with runtime database metadata, and adds targeted tests to validate the behavior.

Changes:

• Resolve stored procedure parameter metadata from runtime DB metadata when config parameters are missing/partial.
• Merge config + DB parameter metadata, preferring config values for overlapping fields.
• Add MCP unit tests covering metadata-only discovery and config-overrides-DB merging.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/Azure.DataApiBuilder.Mcp/BuiltInTools/DescribeEntitiesTool.cs	Adds metadata resolution for stored procedure entities and merges DB/config parameter metadata in describe_entities output.
src/Service.Tests/Mcp/DescribeEntitiesStoredProcedureParametersTests.cs	Adds unit tests validating parameter discovery from DB metadata and config-overrides behavior.

[Aniruddh25]

Want to know reasoning behind why the bug happened.

[RubenCerna2079]

Hey just wanted to let you know that it seems this PR is related to a bug that I created for 2.0. Might be a good idea to check it and see if it can be fixed on this PR or as a follow up. #3435

[anushakolan]

Hey just wanted to let you know that it seems this PR is related to a bug that I created for 2.0. Might be a good idea to check it and see if it can be fixed on this PR or as a follow up. #3435

Thanks for linking these! They share the same root cause: parameter metadata is read only from config, not from runtime DB metadata.

PR #3425 fixes describe_entities (AI agents can now discover parameters).

Bug #3435 needs a follow-up PR to fix DynamicCustomTool.BuildInputSchema() the same way - it currently only reads Entity.Source.Parameters from config, not from IMetadataProviderFactory.

The fix requires passing IServiceProvider through CustomMcpToolFactory to DynamicCustomTool so it can access runtime metadata for schema building.

[anushakolan]

Want to know reasoning behind why the bug happened.

Original implementation only read config (Entity.Source.Parameters), ignoring runtime-discovered parameters from IMetadataProviderFactory. The fix merges both: DB metadata as base, config as overrides. May be @souvikghosh04 can add anything I missed.