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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only that the result includes current date/time; it says nothing about format, timezone, or other fields, which is a modest addition over the annotations.

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?

Two short, front-loaded sentences that get to the point immediately. The trailing 'etc.' is filler and slightly weakens precision, but overall it is compact and easily scanned.

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?

For a zero-param, no-output-schema tool the description covers the essentials, but 'system information like current date and time' with 'etc.' leaves the actual contents ambiguous, and nothing clarifies return shape or timezone. Adequate but with a clear gap for an agent that needs to know what it will receive.

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 tool takes zero parameters, so there is no parameter semantics to convey; baseline 4 applies. The description does not misrepresent any inputs.

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 a clear verb ('Getting') and resource ('system information'), and names a concrete example ('current date and time') that matches the tool name system_get_context. It stops short of enumerating the full return payload (the 'etc.' leaves scope fuzzy) and offers no sibling differentiation, but no sibling overlaps this concern.

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?

It gives one usage trigger ('when calculating time intervals'), which implies context, but provides no when-not guidance and names no alternatives. With a sibling set of unrelated list/get tools, there is little routing ambiguity, so implied usage is acceptable but thin.

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