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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely useful behavior: pagination runs in 100-row pages and offset advances through them, and the input is mutually exclusive. No auth/rate-limit or error context, but that is minor for a public read endpoint.

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?

Three sentences, zero filler, and the core action is front-loaded ahead of the constraint and the sibling pointer. 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?

An output schema exists so return values need no explanation, and the description covers entry point, argument exclusivity, sorting, and pagination. It stops short of describing what a 'release row' contains or any failure mode, which is acceptable but not exhaustive.

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 baseline is 3, but the description adds the one-of constraint across id/path/url that the schema itself does not enforce, plus the page size that gives offset meaning. That is real value beyond the property descriptions.

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 and resource: 'List release rows from a public Box Office Mojo brand page.' An agent can tell this is a brand-page row lister, not a title or calendar endpoint. It does not explicitly contrast with the sibling boxofficemojo_release, which also returns release data, so full sibling differentiation is missing.

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 discovery path explicitly ('Use boxofficemojo_brands to discover brand identifiers') and states the selection rule ('Pass exactly one brand id, path, or URL'). No when-not-to-use guidance is given, but the entry-point routing is clear.

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