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

Annotations already cover safety (readOnlyHint=true, idempotentHint=true, destruction false), so the bar is lower. The description adds a useful domain constraint: there are exactly 20 canonical markets, and UK vs GB mapping is handled. However, it doesn't say whether an unrecognized market returns an error, null, or a fuzzy match.

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 the purpose question and followed immediately by the concrete mapping rule. 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?

The tool is simple (one param, output schema present), and the description supplies enough domain context to invoke it correctly, including the canonical market count and alias handling. The only gap is failure behavior for non-canonical inputs, which is minor given the output schema exists.

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 0% and there is a single required 'market' parameter with no enum. The description gives examples (FR, UK, US, Japan) and a critical UK/GB alias rule, which is genuine added meaning beyond the bare string schema. Baseline 3 for a one-parameter tool where the description partially compensates.

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?

The description states a specific verb (resolve) and resource (a market to one of the 20 markets on the record), and gives concrete examples (FR, UK, US, Japan). The phrasing 'Where is the media bought?' frames the domain purpose. It is clearly distinguishable from siblings like resolve_actor and resolve_gtin, which resolve other entity types.

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?

Usage is implied — an agent would call this when it has a user-supplied or free-text market that needs normalization to the canonical 20-market vocabulary. The UK/GB acceptance note gives a hint about input tolerance, but there is no explicit guidance on when to use this versus alternatives or what happens on an unresolvable market.

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