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

Annotations already declare readOnly, idempotent and closed-world, so the safety profile is covered. The description adds genuine value by enumerating what the comparison reports (memory, price, models fully in memory, estimated speed per model) — effectively the return shape, since no output schema exists. It does not clarify that speeds are estimates subject to context length, nor how it behaves with unknown slugs.

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?

It is a single dense sentence with the resource front-loaded, which is good. But it is a run-on that packs five concepts into one clause chain, and 'in a market' is a confusing way to say prices are market-specific.

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 output schema, the description does the right thing by listing the reported fields, which is the main completeness requirement here. However, in a six-tool family it omits which sibling supplies the slugs and any note on currency or units for price and speed, leaving the agent to infer call prerequisites.

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 100%, so both slugs, the market enum and the context enum are fully documented in the schema. The description only implicitly ties 'in a market' to the market parameter and 'runs fully in memory' to the context parameter, adding no syntax or guidance beyond the schema — baseline 3 applies.

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 (graphics cards or machines) and the operation (side-by-side comparison) and lists the compared dimensions, so an agent can tell it apart from find_hardware or hardware_details. It never uses a clean verb like 'compare', and the phrase 'in a market' is ambiguous, but the intent is unmistakable.

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 statement of when to choose this over hardware_details (single item) or best_hardware (ranking), nor any prerequisite such as needing slugs obtained from find_hardware first. The 'two ... side by side' framing only weakly implies the pairwise use case.

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