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

With only readOnlyHint=true, the description adds substantial behavioral context: data sources (latest stored holdings, Bullrun mappings), explicit statement about factor/thematic unavailability, and how coverage metrics prevent misrepresentation of partial data. It also reaffirms read-only. No contradiction with 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?

Three concise sentences, each adding distinct value: what it calculates, data-source caveat, and coverage interpretation. No fluff or duplication of schema defaults. Front-loaded with the primary purpose.

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?

Given the existence of an output schema and readOnlyHint, the description covers key context: input basis, limitations, and partial-data handling. It is sufficiently complete for a read-only exposure calculation tool without needing to enumerate return fields.

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 only 33% (only ticker has a description). The description partially compensates by naming sector/country/currency/asset, which maps to the types enum, but it does not explain the limitPerType parameter or its effect on coverage. Some meaning is added, but not enough for a low-coverage schema.

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 starts with a specific verb ('Calculate') and clearly identifies the resource (ETF exposures from latest stored holdings and Bullrun mappings). It lists the exposure dimensions (sector, country, currency, asset), distinguishing it from siblings like get_etf_holdings or get_etf_risk.

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 its use case (calculating exposures) and notes that factor/thematic look-through are unavailable, which is an exclusion. However, it does not explicitly mention when to use this tool over alternatives or reference sibling tools, so guidance is only implied.

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