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

Annotations already declare read-only, idempotent, closed-world, non-destructive behavior, lowering the disclosure burden. The description adds scope (NZX company) and a 12-month window for net buying/selling, but omits auth, freshness, coverage limits, and pagination behavior.

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 tool's purpose and return contents, followed by trigger examples. The return-category list is somewhat detailed for a tool with an output schema, but it aids selection rather than bloating the text.

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?

For a single-parameter read tool with rich annotations, 100% schema coverage, and an output schema, the description supplies enough purpose, scope, and trigger context to invoke it correctly. Nothing essential is missing.

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% and ticker is fully documented as an NZX ticker symbol with examples. The description only implies 'for an NZX company' and adds no syntax or validation semantics beyond the schema.

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 ('Get') and resource ('insider/director ownership data') for NZX companies. It spells out the return categories, but does not explicitly distinguish itself from sibling tools such as get_insider_trades or get_shareholders.

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 trigger phrases ('Use when asked about insider ownership, skin in the game, director holdings, founder holdings, or insider trading activity') for a specific company. It does not name alternative tools or when-not-to-use conditions, so it stops short of full routing guidance.

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