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

Annotations already declare read-only/non-destructive, so the description focuses on latency and cost context: the figures are valued at the metal prices of their model date, which is returned alongside them, not at today's prices. That stale-price caveat is real behavioral context an agent needs to interpret results correctly, though return shape/pagination is not covered.

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 sentences, return fields front-loaded, with the pricing caveat last. 'exact, fast and free' is slightly promotional but functions as a differentiator, so little is wasted.

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?

There is no output schema, so the description carries the return burden and does so by enumerating the fields (NAV/share, P/NAV, commodity, assets, model date) and explaining the list mode. Missing only finer points like result ordering or coverage-list size, which are minor.

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% and the parameter description already documents ticker/company-name forms and the omit-to-list-all behavior. The description's restatement of the no-ticker case adds no syntax or format detail beyond the schema, so baseline 3 applies.

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?

Names a specific verb and resource ('Returns Harcourt Valuations' published net asset value per share') and enumerates the returned fields, plus the list-all behavior when no ticker is supplied. It doesn't name the sibling ask_mike, so the distinction from an NL query tool is only implied by 'direct read ... exact, fast and free'.

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 no-ticker case is stated ('or the whole coverage list when no ticker is given'), which is genuine usage guidance for the only parameter. However, it never explicitly says when to prefer this over ask_mike, nor any exclusions — the contrast with the sibling is left to inference.

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