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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuine behavioral context by flagging that results are 'paginated' and by previewing the item fields (score, quote, helpfulness, spoiler flag). It stops short of noting rate limits or page-size clamping, but adds real value beyond the annotations.

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, front-loaded with the core action and scope, followed immediately by routing guidance. No filler or redundancy.

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, the description needn't explain return values, and annotations cover safety. It covers purpose, routing, and pagination adequately for a read-only fetch tool, leaving only marginal gaps like pagination limits or sort semantics that the schema already handles.

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 page, slug, sort, and per_page are all documented by the schema itself. The description adds nothing parameter-specific beyond 'paginated', which is the expected baseline when the schema does the heavy lifting.

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 (Fetch), resource (Metacritic user-review items), scope (for a movie), and even enumerates the returned fields (score, quote, helpfulness, spoiler flag). It explicitly distinguishes itself from the critic-reviews sibling and the aggregate-title sibling.

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?

Names the two alternatives directly and the condition that selects each: 'Use metacritic_movie_critic_reviews for professional reviews or metacritic_movie for the title's aggregate detail.' This leaves no inference needed about which tool to pick.

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