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

Well beyond the readOnly/idempotent/openWorld annotations, it discloses the live data source (Registrar of Companies dataset on data.gov.il), staleness behavior (amended returns and late registrations may not appear), the verdict set including 'unknown is a first-class answer and is not charged,' and the Ed25519-signed receipt checkable offline against /.well-known/factstamp-issuer.json. These are exactly the behavioral traits an agent needs and none are in the structured fields.

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 core purpose is front-loaded in the opening clause and the subsequent sentences each carry material information (data source, exclusions, verdicts, receipt). It is dense and sprawling on the first sentence but still earns most of its length rather than padding.

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 fully compensates by describing the seven returned sections, the receipt and coverage block, and the four possible verdicts. An agent has everything needed to call it and interpret the result.

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 there is a single parameter, so the schema already documents the accepted formats. The description restates the same number/name semantics without adding new syntax or format detail, so baseline 3 applies.

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+resource ('Israeli company lookup and company register check') with explicit lookup keys (nine-digit company number with check digit, or registered name in Hebrew/English) and enumerates exactly which fields come back. The Israel scope distinguishes it from check_entity_file_ca and the other entity siblings without needing their 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?

Frames the tool's boundaries clearly: it is 'not advice, not a credit check and not a KYB service,' and it declares its non-coverage (officers/directors/shareholders, financial statements) and freshness caveat. It stops short of naming a sibling alternative or a when-not-to-use-this-tool routing rule, so it is context-rich but not fully explicit about alternatives.

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