[Marina-L-Stoyanova]

C#-only changes in server/; src/ and ThemeTools.cs are untouched.

• --debug log under parallel calls: ToolLog.Write now locks around the append. Before, concurrent calls collided and the error was swallowed, so entries went missing.
• stderr noise: the default log level is now Warning, and Information only with --debug. The "ready (data: …)" line is unchanged.
• Input limits:
  • limit is clamped to 1–50, so limit: 0 or a negative value no longer returns "no results".
  • New shared helper ToolInput.CheckLength(name, value, max, min) returns isError with a clear message (e.g. "query is too long (700 characters), max 128 characters").
  • It's applied to every string parameter that declares length limits in ComponentTools, SearchTools and DocsTools, and it runs before any searching. It's ready to reuse in ThemeTools.cs.
• Headings: tool output now starts with ## instead of #, and the sections below it moved down one level (### Properties, #### Example 1, …). ThemeTools.cs still uses # until it gets the same change.
• search_wpf_docs(control: "ThemeManager"): control-name matching now ignores spaces as well as hyphens, so it finds the 10 "IG Theme Manager" topics.
• READMEs: the Troubleshooting entry for --debug now mentions the SDK's stderr logging.

Tests

New IS_DOTNET checks in scripts/smoke-test.ts:

• limit: 0 returns one result
• an over-long query and a blank query both return isError
• control: "ThemeManager" finds the "IG Theme Manager" topics
• stderr has no info: lines without --debug
• 20 parallel calls give 20 --debug log entries

[Copilot]

🟢 Approval recommended

The focused changes have no identified blocking issues in static review; runtime tests were not executed.

No open issues 🎉

What changed in this PR

Improves reliability, input validation, and output formatting in the C# WPF MCP server while leaving the TypeScript runtime unchanged.

Changes:

• Serializes debug-log writes and reduces default stderr logging.
• Enforces input limits, adjusts headings, and improves documentation control matching.
• Adds C# smoke checks and updates troubleshooting guidance.

File	Description
server/​Tools/​ToolLog.cs	Serializes concurrent log appends.
server/​Tools/​ToolInput.cs	Adds shared string-length validation.
server/​Tools/​SearchTools.cs	Validates queries, clamps limits, and adjusts headings.
server/​Tools/​DocsTools.cs	Validates inputs and improves matching and headings.
server/​Tools/​ComponentTools.cs	Validates inputs and adjusts headings.
server/​README.md	Documents SDK debug logging.
server/​Program.cs	Sets logging verbosity based on --debug.
scripts/​smoke-test.ts	Adds validation and logging regression checks.
README.md	Updates debug troubleshooting guidance.

_{Review effort: Balanced}