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Minimal stdio MCP server exposing timezone tools for getting current time and converting timestamps across IANA timezones.
Two tools with clear verb-noun naming (current_time, convert_time) and explicit tool annotations. Descriptions are present (60-70 chars) but lack actionable context for LLM selection. Input schemas are properly typed with descriptions, but parameter descriptions are minimal (15-30 chars) and lack format/constraint guidance. No output schema documented. Error handling is basic (throws on invalid timestamp) but lacks recovery guidance. Missing idempotency hints and dependency documentation.
Convert an ISO-8601 timestamp into another IANA timezone.
Return the current date and time in an IANA timezone.
Parameter descriptions are too brief (15-30 chars). 'IANA timezone, e.g. Europe/Paris' lacks format constraints, valid range, or guidance on what happens with invalid input. LLMs cannot infer whether 'UTC+5' or 'EST' are acceptable.
No output schema documented. Tool descriptions do not specify what fields are returned or their types. LLMs cannot plan downstream operations or extract structured data reliably.
Error handling lacks recovery guidance. When timestamp is invalid, error message 'Not a valid timestamp: ...' tells LLM nothing about what to do next. Should suggest format or alternative tools.
Tool descriptions lack WHEN-to-use context. 'Return the current date and time' does not explain when to call this vs convert_time, or what use cases it enables. LLMs may misselect tools.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | D | 57 | 2026-07-28+ | v2 |
No idempotency guarantee stated. Both tools appear idempotent (read-only, deterministic), but this is not documented. Agents need explicit confirmation that repeated calls are safe.