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 fully covered without description help. The description adds genuinely new behavioral context: the fixed 30-day window and the specific metric definitions. It stops short of saying whether the numbers cover all workspace models or only ones the caller follows.

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?

A single front-loaded sentence that opens with the time window and the subject before enumerating metrics. It is efficient, though the colloquial phrase 'beat standing still' is slightly ambiguous as a baseline description.

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 no parameters, a full output schema, and annotations covering safety, the description only needs to explain what is measured, which it does. The one unresolved question is scoping, i.e. whether results cover all models or just the caller's followed models.

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 the schema baseline of 4 applies. The description adds no parameter information, and none is needed; the time window is fixed and therefore not exposed for the agent to reason about.

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 names the resource (a performance scoreboard for DataSnack's models and agents) and enumerates the three metrics it reports: forecast error, comparison to a naive baseline ('beat standing still'), and directional accuracy. It is clear what the tool returns, but it never distinguishes itself from the related sibling 'calibration', which an agent could reasonably pick for similar accuracy questions.

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?

There is no when-to-use guidance, no named alternative, and no note that the window is fixed to the last 30 days and cannot be changed. The agent must infer from the metric content alone that this is an at-a-glance overview rather than a drill-down tool.

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