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

With no annotations provided, the description carries the full transparency burden. It discloses important null-handling semantics (null means 'not measured'/'untested', never assumed allow or zero) and the constraint that only claimed domains are supported. It could add error cases or permissions, but it provides substantial behavioral detail beyond a generic API description.

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 relatively long but every sentence adds useful information: purpose, domain requirement, null semantics, and scope limitation. It is well-structured and front-loads the core purpose before explaining edge cases. Slightly more verbose than necessary but not wasteful.

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 compensates by explaining key return semantics (can_read, cited/tracked null behavior) and explicitly stating what the tool does not measure (traffic). For a single-parameter tool, this provides sufficient context for an agent to invoke it correctly and interpret results, though a formal response structure would improve completeness.

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 input schema already describes 'domain' with 100% coverage. The description adds meaningful context by introducing 'cataloged domain' and 'Claimed domains only', clarifying that the domain parameter must be an already-claimed/cataloged domain, not just any company domain. This goes beyond the schema's basic example.

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 clearly states the tool retrieves per-engine access and citation data for a cataloged domain. It uses a specific verb ('get') with a precise resource ('per-engine picture') and differentiates from siblings by emphasizing it covers both robots.txt access and citation counts for each engine, not just citations or domains.

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?

It communicates when to use the tool ('Claimed domains only') and clarifies what it does and does not cover ('Access and citations only; nothing about traffic'). However, it does not explicitly name alternative tools for citation-only or traffic-related queries, though the context implicitly separates it from siblings like get_citations.

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