Find location ids

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

Annotations already cover read-only/non-destructive/open-world, so the safety profile is handled. The description adds real behavioral context beyond that: the result set is a global superset, not filtered by account eligibility, and writes using an out-of-policy country are rejected. It doesn't cover pagination or how 'limit' behaves, which keeps it from a 5.

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 sentences, front-loaded with purpose followed by the critical caveat, with no filler. The 'MEASURED:' prefix and capitalized 'NOT' are slightly awkward stylistically but the emphasis is earned by the importance of the warning.

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?

For a two-parameter lookup with no output schema, the definition gives purpose, expected output (ids), and the most consequential gotcha about unvalidated results. The remaining gaps — limit behavior and query matching rules — are minor but real given no parameter documentation exists anywhere else.

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 burden. It does clarify the query dimension by naming the entity types being matched (countries, regions, markets) and that ids are the product, but says nothing about match semantics (exact vs prefix) or what the 'limit' parameter does. Partial compensation only.

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 names a concrete verb ('look up') and specific resources ('countries, regions and markets'), and states the outcome ('get their ids'). No sibling tool covers geo/market lookup, so the agent can separate it from campaign/ad/insights tools purely from this sentence.

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 context is stated explicitly: this is for 'campaign targeting', i.e. resolve names to ids before building targeting. The description also warns that returned results are not necessarily targetable by the account, which is guidance on how to interpret and use results. It stops short of naming an alternative or stating when not to call it.

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