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An MCP server providing tools for generating various kinds of unique IDs.
This is a well-structured utility MCP server with clear, domain-appropriate descriptions and comprehensive input validation via Zod schemas. All 5 tools follow consistent naming conventions (verb_noun pattern: generate_*), have detailed descriptions (194-372 chars, within the baseline 34-392 char range), and include proper parameter schemas with type constraints and min/max bounds. The descriptions go beyond the baseline by contextualizing each ID type (collision resistance for CUID, compactness for NanoID, time-ordering for ULID, standardization for UUID) and explicitly noting trade-offs (e.g., 'predictability makes ULIDs unsuitable for security-sensitive applications'). However, output schemas are not formally documented in code, they return JSON strings rather than structured responses with typed fields. Tool outputs are simple arrays of strings, but the code does not declare the structure to the protocol. Parameters are well-constrained (e.g., length: min 16, max 128; count: min 1, max 1000), but there are no error handling descriptions, if a user passes invalid input, the Zod validation will reject it, but tool descriptions don't explain what happens on validation failure or how to recover. The server is read-only (no state mutations), which simplifies error recovery but is not documented in tool descriptions.
Generate one or more v2 CUIDs (Collision-resistant Unique Identifiers). CUIDs are 36-characters by default and use Node.js' secure random PRNG. CUIDs are optimized for horizontal scalability in distributed systems. They offer strong collision resistance but have higher computational cost. Best for secure applications where uniqueness across multiple servers without coordination is critical.
Generate the current time as an ISO 8601 timestamp. Useful for recording the time with millisecond precision. Strictly not suitable for uses that require absolute uniqueness or unpredictability.
Generate one or more NanoIDs. NanoIDs are 21-characters by default, URL-safe identifiers optimized for compactness and performance. They provide an excellent balance of uniqueness, brevity, and generation speed with collision probability of ~1 in 10^36. A strong default choice for most applications, especially client-side ID generation, but less secure than CUIDs for cryptographic use cases.
Generate one or more ULIDs (Universally Unique Lexicographically Sortable Identifiers). ULIDs are 26-character identifiers that combine a timestamp with random data, enabling chronological sorting while maintaining uniqueness. Ideal for time-series data, event logs, or any context requiring time-ordered records. Note: The timestamp component creates predictability, making ULIDs unsuitable for security-sensitive applications where IDs must not reveal creation time.
Output schema not formally documented. Tools return JSON-stringified arrays but protocol never declares the response structure (array of strings). LLMs cannot reason about response shape for chaining or validation.
Error handling not described. Tool descriptions do not explain what happens when Zod validation fails (e.g., if count > 1000 or length < 16). LLMs cannot predict or recover from validation errors.
generate_iso_timestamp description is sparse and doesn't address when to use this vs other timestamp tools. Description (57 chars) is below the baseline minimum. Also lacks guidance on precision trade-offs or when nanosecond precision is justified.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-22 | C | 61 | 2026-07-28+ | v2 |
| 2026-03-09 | D | 50 | - | v1 |
Generate one or more UUIDs (Universally Unique Identifiers). You may elect to have the UUID presented as a URN and v4 or v7 UUIDs with v7 as the default. Avoid using UUID versions less than 4 unless the user asks for it explicitly. UUID v7 is a 36-character (with hyphens) time-ordered identifier that improves upon earlier UUID versions by combining timestamp and random data. It provides excellent uniqueness guarantees with widespread support across languages and databases. While more standardized than other options, UUID v7's time component makes it less suitable for security contexts requiring unpredictable identifiers.
No idempotency or read-only hints in tool definitions. While all tools are stateless and safe to retry, the protocol does not explicitly mark them as read-only (via idempotentHint or equivalent). An LLM cannot determine from the tool definition alone whether it's safe to retry on timeout.