Get server time

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

No annotations are provided, so the description carries the burden. It clearly conveys that this is a read-only operation that reports server-local time rather than the client's time, and it explains why the tool must actually be invoked. There is no hidden mutation or surprising side effect, though it could optionally mention that time_zone affects the returned representation.

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 exactly two sentences, front-loaded with the main purpose and immediately followed by usage guidance. There is no filler, redundant restating of the title, or unnecessary detail.

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?

This is a simple tool with one optional parameter and an output schema, so the description does not need to explain return values. However, the behavior of the time_zone parameter is not addressed anywhere, so an agent could not confidently know how to request a time in a specific timezone or why the parameter exists.

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 input schema provides only a 'time_zone' property with a default of null and no description. The tool description does not explain how time_zone changes the result, whether null means server-local time, or what formats are accepted. Since the description provides zero parameter explanation and schema description coverage is 0%, this is a clear gap.

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 uses a specific verb ('Returns') and resource ('current date and time on the machine hosting this MCP server'), making the tool's action and result immediately clear. It also distinguishes this tool from siblings like say_hello, echo, and add by defining its exact purpose.

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 explicitly states when to use it: 'Use this whenever the user asks what time or date it is.' It also adds a strong practical instruction by noting that the answer cannot be known without calling this tool, helping the agent avoid guessing.

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