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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description goes far beyond this by disclosing the 13F information table XML discovery, rollup of lots/share classes/put-call splits, the 'most recently filed' semantics, and the historical lag. It also explicitly notes that values are taken directly from the filing. This rich behavioral detail helps the agent understand exactly what happens under the hood.

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 moderately long but every block earns its place: purpose, technical complication (XML table), use cases, exclusions, args, and a full structuredContent example. It is well-organized with headers and front-loaded with the core purpose. No redundant or filler sentences.

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 no output schema, the description compensates fully by providing a complete structuredContent example with field names, types, and sample values. It also covers prerequisites (ticker or CIK), constraints (limit range, historical data), and the source URL. For a tool of this complexity, the description is fully self-contained and leaves no critical gap.

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%: both 'ticker' and 'limit' are fully described in the schema, including default and range for limit. The description largely repeats this information (e.g., 'ticker (string, required): the FILER's ticker or its SEC CIK') without adding new meaning beyond the schema. Baseline 3 is appropriate since the schema carries the semantic burden adequately.

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 opens with a specific verb+resource: 'Institutional stock holdings for a fund manager, from its latest SEC Form 13F.' It clearly distinguishes this tool from siblings by explaining scope (latest 13F), what it returns (holdings with values, shares, lots), and explicit non-use cases (real-time, shorts, non-U.S. filers). This makes the tool's purpose unmistakable.

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 provides explicit 'When to use' (fund holdings, smart money tracking, portfolio research) and 'When NOT to use' (real-time, shorts, non-U.S. filers) with reasoning (45-day filing lag, no short disclosure). However, it does not name any alternative sibling tools, stopping short of the full 'alternatives' criterion for a 5.

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