list_entities

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

The description discloses key behaviors beyond what annotations provide: the default states (ENABLED and PAUSED), the effect of include_archived, and the semantics of text_contains filtering (case-insensitive, applied after fetching). This is significant behavioral context that helps an agent predict results and side effects. Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered; the description adds valuable filtering and default behavior details.

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?

The description is two sentences only: the first states the purpose, the second packs essential parameter details. It is front-loaded with the core action, and every sentence earns its place by conveying non-redundant information. No fluff or 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?

For a tool with 8 parameters and 0% schema coverage, the description covers the most critical parameters (entity, states, include_archived, text_contains) and explicitly notes the filtering behavior. The 'market' parameter is simple, and ids/campaign_ids/ad_group_ids are likely straightforward filters. The output schema likely documents return structure, so the description does not need to. Minor gaps include potential pagination or limit behavior, but these are acceptable given the annotations and output schema.

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?

With 0% schema description coverage, the description must compensate. It explains the 'entity' parameter by listing valid values, clarifies 'states' default, and specifies the behavior of 'include_archived' and 'text_contains'. It does not explicitly explain 'market', 'ids', 'ad_group_ids', or 'campaign_ids', but these are self-evident from their names and the context. The coverage is strong for the complex parameters, though a couple of simpler ones are left to inference.

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 clearly states that the tool lists Sponsored Products entities for a given market, and enumerates all supported entity types (campaigns, ad_groups, keywords, etc.). This distinguishes it from sibling tools like list_profiles or get_plan, which target different resource categories. The verb 'list' and resource 'entities' are specific and unambiguous.

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 description implies usage—when you need to list any of the mentioned entity types—but does not explicitly state when to prefer this tool over alternatives like list_profiles or get_plan. There is no 'use this when' phrasing or exclusions for cases where another tool would be more appropriate. The context is clear enough for a generic list tool, but it lacks explicit routing guidance.

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