Improve MCP tool error reporting

[mxstbr]

Motivation

• Provide consistent, developer-friendly error responses for MCP tools so callers receive detailed validation and debugging context.
• Surface Zod validation issues, input payloads, and stack traces in the tool response so automated clients can react or surface helpful diagnostics.
• Reduce time-to-debug for failures across calendar, chores, finance, and telegram MCP tools by wrapping handlers with a common error formatter.

Description

• Add app/lib/mcp/tool-errors.ts implementing buildToolErrorResponse and withToolErrorHandling to format validation issues and include input context and stack traces.
• Wrap MCP tool handlers in app/lib/calendar.ts, app/lib/chores.ts, app/lib/finance.ts, and app/lib/telegram.ts with withToolErrorHandling so failures return structured error payloads instead of raw exceptions.
• Tighten input validation and messages by adding clearer Zod schemas (e.g. isoDateSchema messages, message min length) and improve thrown error text for calendar/finance operations.
• No UI changes were made; changes are limited to MCP tool registration and error handling infrastructure.

Testing

• Ran TypeScript check with pnpm tsc --noEmit which completed successfully.
• Ran full build with pnpm build, which failed due to Next.js failing to fetch Google Fonts (Inter) from Google Fonts because of TLS/network restrictions, unrelated to these code changes.
• Prettier formatting was applied as part of the commit hooks (auto-format step completed successfully).

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Codex Task

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Project	Deployment	Review	Updated (UTC)
mxstbr.com	Ready	Preview, Comment	Jan 11, 2026 5:29pm