MCP Server Framework

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden and does well by disclosing key behavioral traits: it returns UTC time, uses strftime formatting, and has a default format. However, it does not mention potential limitations like system clock dependency or timezone handling beyond UTC.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is appropriately sized and front-loaded, starting with the core purpose, followed by clear sections for Args and Returns. Every sentence earns its place by providing essential information without redundancy or fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's low complexity, one parameter with full description coverage, and the presence of an output schema (which handles return values), the description is complete enough. It covers purpose, parameter details, and return behavior adequately for this simple utility tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds significant meaning beyond the input schema, which has 0% coverage. It explains that the 'format' parameter is a 'strftime format string' with a specific default, clarifying syntax and usage that the schema alone does not provide, fully compensating for the low schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with a specific verb ('Get') and resource ('current date and time in UTC'), distinguishing it from siblings like 'get_timestamp' or 'parse_timestamp' by focusing on real-time UTC retrieval rather than processing or conversion.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage for obtaining the current UTC time, but does not explicitly state when to use this tool versus alternatives like 'get_timestamp' or 'parse_timestamp'. It provides clear context but lacks explicit exclusions or comparisons to sibling tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.