jaegermcp: enforce MaxSpanDetailsPerRequest in get_span_details

[jkowall]

Motivation

• get_span_details accepted unbounded span_ids lists even though the MCP config already exposed MaxSpanDetailsPerRequest.
• That made the configured guard ineffective and let callers drive unnecessary memory and CPU work.
• Per review feedback, the handler should trust validated config rather than carrying its own fallback.

Description

• Pass MaxSpanDetailsPerRequest into the get_span_details handler from the server.
• Reject requests whose span_ids exceed the configured limit.
• Validate MaxSpanDetailsPerRequest in Config.Validate() so the handler can rely on it.
• Remove the redundant handler-side defaulting and update tests to construct handlers with an explicit configured limit.
• Add coverage for the invalid low-end config case and the oversized span_ids request case.

Testing

• Ran the repo-equivalent format/lint steps successfully (make fmt/make lint had to be executed manually because this Windows + WSL environment cannot execute the repo shebang scripts directly).
• Ran go test -race ./cmd/jaeger/internal/extension/jaegermcp/....
• Ran make test; it still fails in this environment due unrelated existing failures in cmd/anonymizer/app/uiconv and internal/uimodel/converter/v1/json.

[jkowall]

Porting over Yuri's review note from the fork PR for context:

"Redundant, config value should be validated by config struct's Validate method."

Addressed in this PR by:

• removing the handler-side fallback/defaulting in get_span_details
• validating MaxSpanDetailsPerRequest in Config.Validate()
• keeping the request-size enforcement in the handler, with tests using an explicit configured limit

My reply: updated accordingly. The handler now relies on validated config instead of carrying its own backup default.

[Copilot]

Pull request overview

This PR makes the get_span_details MCP tool respect the existing MaxSpanDetailsPerRequest configuration, preventing unbounded span ID requests from driving excessive CPU/memory work.

Changes:

• Pass MaxSpanDetailsPerRequest from the MCP server into the get_span_details handler.
• Enforce the max span ID count in get_span_details request validation.
• Strengthen config validation and expand unit test coverage for invalid config and oversized requests.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
cmd/jaeger/internal/extension/jaegermcp/server.go	Wires MaxSpanDetailsPerRequest into the get_span_details handler constructor.
cmd/jaeger/internal/extension/jaegermcp/internal/handlers/get_span_details.go	Adds a per-request span_ids length guard based on configured max.
cmd/jaeger/internal/extension/jaegermcp/internal/handlers/get_span_details_test.go	Updates handler construction in tests and adds coverage for oversized span_ids.
cmd/jaeger/internal/extension/jaegermcp/config.go	Adds an explicit low-end validation for MaxSpanDetailsPerRequest.
cmd/jaeger/internal/extension/jaegermcp/config_test.go	Adds a test case for too-low MaxSpanDetailsPerRequest.

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[yurishkuro]

Suggested change

	"span_ids must not exceed %d items",
	"Number of input Span IDs must not exceed %d items",

[yurishkuro]

why remove validation?

[yurishkuro]

why do this manually instead of via govalidator.ValidateStruct ?