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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds that results are aligned side by side across models and capped at 4, but says nothing about ordering, what happens if a slug is invalid, or how the comparison is presented.

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?

One short sentence with the most useful information (equivalence to get_model, 2-4 models, side-by-side output) front-loaded. It is efficient, though slightly under-specified rather than genuinely tight.

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 one-parameter read-only tool with annotations, this is close to adequate. The gap is that with no output schema, the description defers the return shape entirely to 'the same facts as get_model' instead of naming what is compared.

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%, but the single parameter (slugs) is self-explanatory and the schema already encodes minItems 2 / maxItems 4. The description merely restates the '2 to 4' bound without explaining slug format or how to obtain them.

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?

Names a specific operation (side-by-side comparison) and anchors it to the sibling get_model, making the single-vs-multi distinction clear. The vague part is 'the same facts' — it never says what facts are compared, so the resource content is only defined by reference.

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 '2 to 4 models' clause implies when to reach for this over get_model, but there is no explicit 'use this instead of calling get_model N times' statement and no guidance on what to do outside that range. Usage is inferable rather than stated.

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