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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds meaningful context: the slugs must be 'known' (pre-existing) and that the comparison uses specific metadata fields. It repeats the telemetry requirement already present in the schema, but that repetition is minor. No contradiction with annotations exists.

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 two sentences: the first states the core purpose and scope, and the second provides essential telemetry usage. There is no fluff, and key information (count range, metadata fields, telemetry rules) is front-loaded. Every sentence earns its place.

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?

The tool has a rich output schema and strong annotations, so the description does not need to explain return values or safety. It covers the core input semantics and telemetry requirements. However, it does not mention how the comparison is returned or any handling of invalid slugss—though 'known' hints at validity. Given the presence of output schema and annotations, this is adequate but not exhaustive, so a 4 is appropriate.

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 describes the 'slugs' array constraints but gives no semantic meaning for the slugs; the description adds that they are 'Recipe Signal recipe slugs' and that they must be 'known', which directly clarifies what values are acceptable. The telemetry parameter is already well-described in the schema, so the description's focus on slugs fills the main gap. With schema coverage at 50%, the description compensates effectively.

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 states a specific verb ('Compare'), a specific resource ('two to five known Recipe Signal recipe slugs'), and the comparison dimensions ('published time, rating, rating volume, yield, cuisine, and publisher metadata'). This clearly distinguishes it from siblings: get_recipe fetches a single recipe, search_recipes finds recipes, and get_comparison_guide provides guidance rather than direct comparison.

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 description clarifies when to use this tool: when you have two to five known Recipe Signal slugs to compare. It does not explicitly name alternative tools or provide exclusion criteria, but the 'known slugs' constraint gives a clear prerequisite. The telemetry instruction is useful invocation guidance but not about choosing among alternatives, so this is a 4 rather than 5.

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