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 that the source is 'credential-free', which usefully signals no auth is needed, but it says nothing about return volume, pagination limits, or ordering. A 3 is appropriate given annotations carry the rest.

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?

One compact sentence that front-loads the core action and scoping, followed by a short disambiguation clause. No filler; every clause 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?

With an output schema present, return values need not be described. Parameters are fully schema-documented and the alternative tools are named, so nothing an agent needs to call this correctly is missing.

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 both parameters and their allowed values are already documented in the schema. The description adds only marginal meaning ('offset pages the chart', area is worldwide or domestic), which duplicates the enum-like schema text. Baseline 3 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) and resource (movie rows from Box Office Mojo's lifetime-gross chart), with scope clearly bounded. It also names the sibling tools it is not, so an agent can distinguish it from the year-specific charts without opening either 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?

Explicitly routes the agent: use boxofficemojo_year_worldwide or boxofficemojo_year_domestic for year-specific charts, implying this tool is for the all-time/lifetime chart. Both the condition and the alternatives are named.

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