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 the 'exactly one identifier' input constraint and the region-grouping semantics of the response, but says nothing about auth needs or data freshness beyond what annotations provide.

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 short sentences: what it returns, how to pass input, and the prerequisite discovery step. Front-loaded with the outcome and no 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?

An output schema exists, so return values need not be documented. Input selection and the discovery prerequisite are covered, leaving only the distinction from the single-release siblings unaddressed, which is a minor gap for an otherwise complete definition.

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 schema documents each field, but the schema does not encode that the three identifier parameters are mutually exclusive. The description's 'Pass exactly one release-group id, path, or URL' supplies that missing constraint, adding real value over the structured fields.

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 (market release rows grouped by region for one Box Office Mojo release group), which is a distinct shape from other boxofficemojo siblings. It also names boxofficemojo_title as the discovery entry point, steering the agent away from guessing.

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?

Explicitly tells the agent to run boxofficemojo_title first to discover release groups, and constrains input to exactly one identifier. It does not distinguish this tool from boxofficemojo_release or boxofficemojo_release (single-release) siblings, so the routing is clear but not fully exclusive.

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