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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the description's added value is in disclosure of output behavior: it includes sources and last-checked dates, and explicitly makes no scores or invented prices. That is a meaningful honesty/uncertainty contract an agent would not get from annotations alone.

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 dense sentences: what is compared and along which dimensions first, then the output-integrity guarantee. No filler, no restatement of the tool name.

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 a single fully documented parameter and no output schema, the description carries the return-value burden and does so partly, naming sources, last-checked dates and the absence of scores/prices. It does not say what happens with an unknown or unpublished slug, a minor but real gap.

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 the schema already documents the slugs array, its 2-3 item bounds, uniqueness and the 'exact slug from search_tools' example. The description only echoes the 'two or three distinct' constraint; it adds no format or sourcing detail 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?

States a specific verb (compare) and resource (two or three distinct published tools) plus the exact comparison dimensions: pricing label, official pricing page, platforms, any-store support, delivery kind. This clearly separates it from single-tool siblings like get_tool, though no sibling is named explicitly.

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 constraint 'two or three distinct published tools' implies the use case (side-by-side evaluation of published entries), but there is no explicit when-to-use/when-not guidance and no routing to get_tool or find_alternatives for the single-tool or discovery cases.

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