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

With no annotations, the description carries the behavioral burden. It discloses the returned fields and the billing model ('Flat 5 points per successful run'), and 'Get' implies a read-only operation. It does not cover authentication, rate limits, or error behavior, so it stops short of a 5.

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 front-loaded sentences with no filler: the first states exactly what is retrieved and by what identifiers, the second adds the cost model. Every sentence earns its place.

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 simple one-parameter read tool with no annotations or output schema, the description supplies the key return fields and billing information. It could be more complete by explicitly routing name-based searches to run_ee_companies_search, but nothing essential is missing for correct invocation.

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 the single parameter is fully documented in the schema with an example. The description restates the accepted input types but adds no syntax or format detail beyond what the schema already provides, so the 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 and resource: 'Get one company from the Estonia registry' by registration number or registry URL. It also enumerates the returned fields, making it distinguishable from run_ee_companies_search (which is for searching rather than a single-company lookup).

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 clearly frames the usage context: lookup of a single Estonia company by registration number or registry URL. It does not explicitly name run_ee_companies_search as the alternative for name-based searching, so it lacks the when-not/alternatives specificity of a 5.

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