get_vnstat_data

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds period scoping and default behavior, which is useful but does not disclose details like output format or whether data is per-interface or aggregated. The annotations carry the main behavioral burden, so a 3 is appropriate.

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 two sentences with no filler. The core action is front-loaded, followed by the parameter list and a clear usage cue. Every sentence earns its place.

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 simple one-parameter read-only tool with strong annotations, the description is nearly complete. It covers what the tool does, when to use it, and the parameter semantics. It does not describe the response shape, but 'network usage' is reasonably self-explanatory for this use case.

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 coverage is 0% and there are no enums, so the description must fully document the parameter. It does: 'period: day (today — default), month (this month), hour (current hour)'. This gives valid values, their meaning, and the default, fully compensating for the sparse schema.

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 specific verb and resource: 'Get network usage from vnstat'. It also enumerates the supported period values and their meanings, making the tool's purpose unmistakable. This clearly distinguishes it from sibling tools like check_vnstat_status or speed_test.

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 says to use it 'when the user asks about their data usage or bandwidth', giving clear contextual guidance. It does not mention when not to use it or name alternatives, but for a read-only query tool this is sufficient.

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