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

Annotations already declare this as a safe, idempotent, non-destructive, non-open-world lookup. The description adds genuinely useful behavior beyond that: the result is constrained to a fixed set of 20 canonical markets, and input aliases are handled ('UK is the label; GB is accepted'). This normalization rule is exactly the kind of quirk an agent cannot get from annotations or schema.

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, front-loaded with context then the directive, with no filler. The opening question is slightly rhetorical but earns its place by setting domain context cheaply.

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 structure need not be spelled out, and the description still notes the output is one of 20 canonical markets. Input format, examples, and alias behavior are all covered; only explicit when-to-use guidance 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 0%, so the description carries the full burden for the single 'market' parameter. It supplies valid examples and an explicit alias rule (UK label, GB accepted), which materially compensates for the undocumented schema.

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 (Resolve) and resource (a market/jurisdiction), with concrete input examples (FR, UK, US, Japan) and a stated output domain (one of the 20 markets on the record). It does not explicitly distinguish itself from sibling resolvers like resolve_actor or resolve_gtin, but the resource noun makes the difference inferable.

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?

The framing question 'Where is the media bought?' implies the context in which this normalization is needed, but there is no explicit when-to-use, no prerequisite, and no routing to alternatives. Usage is implied rather than stated.

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