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

Annotations already declare a read-only, non-destructive, closed-world operation, and the description adds substantial semantics beyond them: rows are dated notifications, not a register; nothing is summed or merged with SEC data; corrections replace prior versions. That is exactly the behavioral context an agent needs to interpret results.

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?

Front-loaded with purpose, then coverage, then row semantics, then exclusions and alternatives. It is long and the regulator enumeration is dense, but each clause carries actionable information and nothing is redundant.

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 only three parameters, full schema coverage, and no output schema, the description fully carries the burden: it explains what a row contains, which regulators and identifiers are matched, and what the tool deliberately excludes.

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 coverage is 100%, so the ticker, offset, and maxResults semantics are already documented in the schema. The description reinforces the MIC:TICKER convention and bare-ticker US behavior but adds little beyond what the schema already states, fitting the baseline 3.

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?

Specific verb and resource: fetches non-US major-holding notifications for one listing, with ticker format defined. It explicitly contrasts with US filings siblings (13F/13D/13G) and names GetBeneficialOwnership and GetTopHolders, so an agent can distinguish it without opening schemas.

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?

Explicit routing: 'For a US listing use GetBeneficialOwnership ... and GetTopHolders.' It also states exactly which regulators and filing types are covered, and that a bare ticker is answered with US ownership tools, leaving no ambiguity about when to pick this tool.

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