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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description ('Get portfolio statistics') is consistent with those. The description adds the data categories (returns, allocation, risk) but does not disclose additional behaviors such as response formatting, pagination, or required permissions. Given the strong annotations, this is acceptable but not exceptional.

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 concise and well-structured. It opens with a clear purpose statement, then lists the single argument in a standard Args block. Every part earns its place, with no redundant or filler content.

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?

The tool is simple (one parameter) and has an output schema, so the description does not need to detail return values. It conveys the core purpose and parameter semantics adequately. No critical information appears missing for an agent to decide whether and how to invoke it.

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?

The schema only provides the parameter name and type, but the description explicitly states 'portfolio_id: The portfolio UUID', clarifying that the value is a UUID. This adds meaningful semantic clarity over the bare schema, effectively compensating for the 0% schema description coverage.

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 verb 'Get' and the resource 'portfolio performance statistics' with specific dimensions (returns, allocation, risk). This distinguishes it from sibling tools like get_positions or list_portfolios, making its purpose 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 context: it is for retrieving performance statistics for a specific portfolio. However, it does not explicitly state when to use this tool over alternatives, nor does it mention any exclusions or prerequisites. The user must infer usage from the name and description.

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