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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), lowering the burden. The description adds behavioral context beyond annotations: ordering behavior (largest first), return contents (value, share count, reported quarter), and the indexed-data consistency note. Minor edge cases like unknown-manager behavior are not disclosed, keeping it a step below 5.

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 sentences with zero waste: core purpose first, then usage example, then alternative routing. Every sentence earns its place and the key scoping statement is front-loaded.

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 appropriately covers what is returned (value, share count, reported quarter). For a simple read-only 2-param tool, the only small gap is clarity on which quarter is reported (implied latest), but overall an agent has what it needs to call correctly.

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%, so the schema already documents both parameters, making 3 the correct baseline. The description adds small value with concrete manager-name examples ('Berkshire Hathaway', 'Pershing Square') and clarifies the result ordering, but does not need to compensate for schema gaps.

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?

States a specific verb and resource: reports every 13F position for one institutional manager, largest first. It clearly distinguishes itself from manager_changes ('the classic manager-first view') and names the sibling it is not, so an agent can differentiate without opening the schema.

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?

Provides explicit when-to-use guidance ('Give the manager name') and explicitly routes to the alternative condition: 'For what CHANGED since the prior quarter use manager_changes instead.' Nothing is left to inference.

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