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

Annotations already declare this read-only, idempotent, and non-destructive, so the bar is lower. The description still adds real value by disclosing the return shape (each stock plus the sector ETFs holding it, ordered largest weight first) and the Premium entitlement requirement.

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 tight sentences with no waste; the core search purpose is front-loaded and the return shape and entitlement follow in order of importance.

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?

With no output schema, the description usefully describes the result structure and ordering, and flags the Premium gate. Only the absence of guidance on paging or result limits keeps it from a 5.

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 100% on a single required 'query' parameter, so the schema already carries the semantics. The description restates only that the query is a ticker or name, adding nothing beyond the schema's own example.

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 (Find) and resource (sector ETFs and stocks), with the lookup keys (ticker or name). It is recognizably a search tool, though it does not name the sibling detail tools (zensei_stock_detail, zensei_sector_detail) that an agent might pick instead.

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?

Implies usage by saying it looks up tickers or names and notes 'Needs Zensei Premium' as a prerequisite, but it never states when to choose this over zensei_stock_detail, zensei_sector_detail, or zensei_sectors_scan.

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