customer_insights_tiers

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, destructiveHint. The description adds behavioral details: usersPercent sums to ~100% per host product, productId/hosting ignored, and the filtering behavior. No contradiction.

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 fairly long but every sentence adds value. It front-loads the key purpose and then details structure and filtering. Could be slightly more concise, but structure is logical.

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?

Despite no output schema, the description fully explains the return structure (group keys, fields like usersDistribution) and behavior (percentage per host product, date filtering). Also provides a link to the full spec for completeness.

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 100%. The description adds meaning beyond schema: clarifies product is a name (not UUID), case-insensitive, and that omitting it returns all host products. This reinforces and extends schema info.

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 the tool returns 'User-tier distribution of your customers, per month, split by HOST PRODUCT' and explains the grouping keys and value fields. This distinguishes it from sibling insights tools (active users, editions, regions).

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 explains filtering by product (name, case-insensitive), date range, and notes that productId/hosting are ignored. It does not explicitly state when to use this tool vs alternatives, but the context of sibling tools implies distinct purposes.

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