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

Annotations already cover readOnly and openWorld, but the description adds genuinely useful behavior: an upstream error is returned for blocked or malformed pages, and scorecards are conditional ('when available'). It does not discuss caching or response shape beyond what the output schema carries, so a 4 rather than 5.

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?

Four tightly packed sentences: what it returns, how to supply input, error behavior, and alternatives. Scoping and routing information is front-loaded with zero filler.

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 unnecessary. The description still covers data contents, input form, failure mode, and sibling routing, which is everything needed to invoke it correctly.

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 baseline is 3, but the description adds real meaning beyond it: the exact-one-of constraint on two optional params and a concrete example path '/tv/breaking_bad/s01' plus the absolute-URL form. This clarifies selection between url and path in a way the schema does not.

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) and resource (Rotten Tomatoes TV season details) and enumerates the payload (parent-series metadata, episode rows, scorecards). It explicitly distinguishes itself from the parent-show and single-episode siblings, so an agent can route without opening another schema.

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 both alternatives with their selection condition: 'Use rottentomatoes_series for the parent show or rottentomatoes_episode for one episode.' The exactly-one-input constraint is also stated, leaving nothing to inference.

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