get_major_shareholder_changes

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

With no annotations, the description carries the behavioral burden and usefully discloses returned fields and 'Newest first' ordering. However, it does not state that the operation is read-only, explain limit/pagination behavior, or mention auth/rate-limit constraints.

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 front-loaded with the core definition, then adds the SEC analogy, returned fields, ordering, and signal value. Every sentence adds useful context with no wasted language.

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 output schema covers return values, and the description adequately explains the dataset and sort order. However, for a tool whose company parameter has 0% schema description coverage, it is not fully complete because it never clarifies what company identifier format is expected or what limit controls.

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?

The description never mentions the company or limit parameters, and schema description coverage is 0%. With two undocumented parameters and no compensating explanation, an agent must infer meaning entirely from parameter names.

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 resource and scope: 5% block-holding reports showing who crossed or changed a 5%+ stake. The SEC Schedule 13D/13G analogy makes the dataset immediately understandable and distinguishes it from a general largest-shareholders tool.

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 usage context by calling it a 'Key activist/M&A signal,' which tells the agent when this data is valuable. It does not explicitly name alternatives such as get_largest_shareholders or get_insider_trades, so sibling routing is left implicit.

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