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

With no annotations, the description carries the burden. It discloses a key behavioral trait: the data can be stale and lag_days must be checked. It also hints at two different data sources (issuer file vs filing) that produce different answers. This is valuable beyond the schema.

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?

Two sentences, front-loaded with the core purpose and a critical warning. The warning is emphasized with 'ALWAYS'. No wasted words, though the second sentence is a bit dense.

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 description covers the core purpose and a critical caveat, but with no output schema and no parameter documentation, an agent may not know what top_n does or what the return structure looks like. The lag_days warning is helpful but incomplete for a tool with 0% schema coverage.

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 0%, so the description must compensate. It explains the meaning of the output (holdings by weight, age) but does not explain the parameters: ticker is obvious, but top_n is not described at all. The description adds no parameter-level meaning.

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 verb+resource: it returns what a fund holds, by weight, and the age of that data. It distinguishes itself from siblings by emphasizing the holdings/weight focus and the lag_days caveat, though it doesn't explicitly name a sibling alternative.

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 gives clear context: ALWAYS read lag_days before presenting the data, and warns that issuer file reads and filings are not the same answer. It doesn't explicitly say when to use this tool vs alternatives, but the lag_days instruction is a strong usage guideline.

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