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

The annotations already declare that this is a read-only, idempotent, non-destructive, closed-world operation. The description adds useful context about what is compared (plans, API pricing, usage limits, platforms) and that each result carries an as_of date and source, though it does not elaborate further on output behavior.

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 a single front-loaded sentence that immediately states the usage condition and the comparison dimensions. There is no wasted wording.

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?

Given the simple one-parameter input, existing output schema, and rich annotations, the description is nearly complete: it explains when to use the tool and what comparison dimensions are returned. The remaining gap is that it does not help the agent choose between this tool and its siblings.

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 description coverage is 100%, so the single platforms parameter and its 2-4 item constraint are already fully documented in the schema. The description merely restates '2 to 4 specific AI tools' and adds no format or interpretation details beyond the 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 names a specific verb (compare) and resource (AI tools) and states the scope of 2 to 4 tools side by side. It does not explicitly distinguish itself from the sibling tools such as find_free_alternatives or get_pricing_facts, so it falls short of a 5.

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 a clear triggering condition: use when the user wants to compare 2 to 4 specific AI tools side by side. It does not state when not to use the tool or explicitly name alternatives among the siblings, so it is clear but incomplete for a 5.

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