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

The description adds significant behavioral context beyond the readOnlyHint annotation: it explains the response structure (provider count, stored count, covered weight, completeness flag), warns to treat isComplete=false/null as partial data, and discloses the future availability of historical selection. This gives the agent essential interpretation guidance.

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 succinct at four sentences, with the core purpose stated first and additional essential caveats in the following sentences. Every sentence adds material information without redundancy or padding, and it is well-structured for quick parsing.

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 presence of a full output schema, an annotation for read-only behavior, and complete schema descriptions for all parameters, the description covers the remaining critical context: pagination mechanics, data completeness interpretation, and known limitations. No important gaps remain.

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% for all three parameters, so the schema already documents each field meaning. The description adds almost no parameter-level detail beyond what is in the schema, except reinforcing the 'opaque cursor' nature, which the schema also mentions. Baseline score of 3 is appropriate.

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 states a specific action ('Return the latest stored ETF holdings snapshot') with a clear resource ('ETF holdings') and key mechanism ('opaque cursor pagination'). It distinguishes itself from sibling tools like get_etf_exposures or get_etf_snapshot by focusing on the holdings list and its pagination, making the intent 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 clearly indicates this tool provides the latest stored snapshot and explicitly notes that historical as-of selection is not yet available, giving context on when to use it. However, it does not name alternative tools or state when not to use this tool, so it lacks explicit exclusion guidance.

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