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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description usefully enumerates returned image fields, but says nothing about pagination, how the limit is applied, or whether id/url are mutually exclusive. With annotations carrying the safety load, a 3 fits.

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 what the tool returns and then the filtering instruction. No filler, though the field enumeration partially duplicates the output schema.

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 restated, and the type-filter routing is handled. However, for a 4-parameter tool with zero schema coverage, leaving id/url/limit semantics unexplained leaves the agent short of what it needs to call the tool 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 description coverage is 0% across 4 parameters. The description clarifies only 'type' (and points to imdb_image_types for values); id, url and limit receive no explanation anywhere, so the meaning of url vs id and the limit semantics must be guessed.

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 resource and scope: 'IMDb name media index' returning image metadata (URL, dimensions, caption, credited people). The 'name' qualifier implicitly separates it from imdb_title_images, though the distinction is not spelled out.

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?

Gives clear operating context: filter with type, and route to imdb_image_types for accepted enum values. It does not state when to prefer this over imdb_title_images or imdb_name_videos, but the sibling routing guidance is unusually concrete.

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