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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds the critical login prerequisite, which is behavioral context not present in annotations. It does not describe any other behaviors, but for a read-only getter this is adequate. No contradiction with annotations.

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 with no redundancy. The prerequisite is front-loaded and the purpose is stated directly. Every word 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 read-only tool with complete schema and safety annotations, the description covers the essential context: the login requirement and the purpose. It does not describe the return format, but with no output schema and a self-explanatory name, this is a minor gap. It is complete enough for an agent to call correctly.

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 schema has 100% coverage and the account_link_id parameter is already well-documented in the schema description, including when to provide it and how it resolves. The tool description adds no additional parameter meaning, so a baseline of 3 is correct.

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 the tool gets client/counterparty info for e-tax invoicing, which is a specific verb and resource. It does not explicitly name a sibling alternative like hometax__etax__business_info__get, but the name and context make the distinction clear. It is clear but lacks explicit sibling differentiation, so a 4 is appropriate.

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 explicitly states the prerequisite: 'REQUIRES prior hometax__session__login call with same account_link_id.' This is a clear condition for use. It does not mention when not to use or name alternatives, but for a simple lookup tool the prerequisite guidance is sufficient.

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