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

Annotations already declare the operation read-only, idempotent, and non-destructive. The description adds a meaningful behavioral caveat: figures are minimums because funds publish only their largest holdings. It also discloses that overlap across funds and coverage share are part of the result, adding value beyond the structured annotations.

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 a single well-structured sentence that front-loads the core action, lists the output facets, and closes with a useful caveat. Every clause earns its place and there is no redundancy with the schema or annotations.

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 an output schema present and full schema coverage, the description provides the essential conceptual model and the key limitation about minimums. It is complete enough for an agent to invoke the tool correctly; the only missing piece is explicit sibling routing, which is covered under usage guidelines.

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%, and the schema already explains holdings as ticker-to-weight/amount maps and base as the reporting currency. The description only frames these as fund holdings aggregated into companies, which is helpful context but not additional parameter-level semantics.

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 names the exact aggregation operation ('added up across funds') and enumerates the outputs (largest names, share of portfolio, overlap names, sectors, coverage). This clearly distinguishes it from sibling tools like compare_portfolios or portfolio_structure, even though it does not use an explicit verb like 'computes'.

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 phrasing 'companies owned through the funds' implies this tool is for aggregated look-through analysis, but there is no explicit statement of when to use it versus alternatives such as portfolio_structure or measure_portfolio. Usage context is inferable rather than directly stated.

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