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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuine behavioral value beyond that: it discloses the ranking factors that determine ordering and that each result carries an explanatory rationale, which an agent cannot infer from annotations or schema. It stops short of covering the cap on results or behavior when no alternatives exist.

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?

Two tight sentences with zero filler, and the substantive content (what is returned and how it is ranked) is front-loaded. The opening is a verbless fragment, which is slightly less crisp than it could be, but nothing is wasted.

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?

An output schema exists, so return-value shape need not be explained, and the description still notes that entries carry rationales. For a three-parameter read tool with full annotation coverage, the only meaningful gaps are the undocumented limit parameter and undefined behavior when a slug has no alternatives.

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 67%: slug and samePricing are documented in the schema, and the description reinforces samePricing as an optional same-pricing-model filter. The limit parameter (1–25) has no description anywhere, and the description does not explain it or give a default, so the baseline 3 for high-but-incomplete coverage is appropriate.

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 precisely (alternatives to a given tool) and even specifies the ranking inputs — freshness, profile completeness, curation, inbound alternative listings — plus that each entry carries a rationale. That is far more specific than the title 'Find alternatives'. It does not explicitly distinguish itself from close siblings like compare_tools or recommend_for_task, which keeps it out of 5 territory.

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 use this versus compare_tools or recommend_for_task, which are the obvious adjacent tools for a similar intent. The only usage-adjacent information is 'Optionally restrict to the same pricing model,' which describes a parameter behavior rather than tool selection guidance.

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