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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description correctly aligns. It adds valuable behavioral context beyond annotations: the $0.01 cost, approximately one-year coverage, and the caveat that an empty result does not prove no earlier change occurred. This enriches the agent's understanding of side effects and limitations.

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 a single focused sentence that front-loads the core purpose and key constraints (cost, coverage, empty-result caveat) without redundancy. Every clause contributes to the agent's decision to call the tool.

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 tool with no required parameters and no output schema, the description covers the essential usage context: what it returns, cost, coverage, and a crucial interpretation caveat. It omits details like pagination handling or the meaning of 'deterministic categories', but these are minor given the tool's simplicity and the annotations covering safety.

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 75% (three of four parameters have descriptions), so the schema already documents most parameter semantics. The description reinforces that company_number must be exact and nine-digit, but does not add new meaning beyond what the schema provides. Baseline 3 is appropriate.

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 verb ('returns') and resource ('recent official filing and status-change events') for an exact Israeli company number, with clear output ordering and content. It distinguishes itself from siblings by emphasizing 'paid' and 'monitoring', which is distinct from the free preview and verification tools.

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 implies a monitoring use case and notes it is low-cost and repeatable, but it does not explicitly name alternatives or state when to use this tool versus the free previews or verification tools. It gives context (cost, exact number) but lacks direct 'use when' guidance.

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