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

Annotations are absent, so the description must fully disclose behavior. It states the output (UTC timestamp) but does not disclose that all 9 input parameters are discarded/ignored, nor does it specify the return format (e.g., ISO 8601, Unix epoch). The schema hints at discarding, but the description itself omits this behavioral detail.

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 a single sentence with no filler. It is efficient and front-loaded with the core purpose. However, it is perhaps too terse given the tool's complexity, but conciseness itself is good.

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?

With 9 optional parameters, no output schema, and no annotations, the description is insufficient. It doesn't explain why the parameters exist, that they are all ignored, or the exact return format. An agent would be confused about how to use this tool correctly, especially given the unrelated parameter names. The description fails to provide the necessary context for safe and correct invocation.

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?

Schema description coverage is 100%, with each parameter individually described (e.g., 'Git ref name; discarded after the shape check'). The description adds nothing about parameters, but the baseline is 3 given the high coverage. The schema already explains the parameters' meaning and discard behavior.

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 states the tool's function clearly: 'Current UTC timestamp.' This is a specific verb+resource (returns a UTC timestamp). It doesn't explicitly distinguish from siblings like 'timezone,' but the name and description make the distinction apparent. No ambiguity about the core 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?

No guidance on when to use this tool versus alternatives. No mention of contexts, exclusions, or when not to use it. The description provides zero usage direction, leaving the agent to infer.

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