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

Annotations already establish the safety profile (readOnlyHint, idempotentHint, openWorldHint, destructiveHint=false), so the description only needs to add context. It does so by disclosing what is compared — pricing, open source status, MCP verification and tool list, rating, votes, launch date, awards, maker — which tells the agent what data will come back beyond the annotation layer.

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?

A single front-loaded sentence with a colon-delimited list of comparison fields; no filler, and the operation and scope are stated before the details.

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 an output schema present, return-value documentation is not required, and annotations cover the safety profile. The description covers operation, cardinality, and compared fields; only edge behavior (fewer than 2 or more than 4 slugs, invalid or non-live slugs) is left unspecified.

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?

The schema documents 'slugs' with 100% coverage including the '2-4 product slugs' cardinality, so the baseline is 3. The description adds the 'live' constraint on eligible products, which is meaning the schema does not carry, justifying a small bump. It adds nothing about slug format or error handling for invalid/duplicate slugs.

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 (side-by-side comparison) and resource (live FastDrop products) and enumerates the compared dimensions, so the agent knows exactly what output to expect. It doesn't explicitly name the sibling it differs from (e.g., get_product for a single product or find_alternatives), but the '2-4 products' scope implicitly separates it from those tools.

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?

Usage is implied: comparing multiple products at once, and the 'live' qualifier hints that only live products are eligible. However, there is no explicit when-to-use/when-not-to-use guidance or routing to alternatives like get_product for a single lookup or find_alternatives for substitutes.

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