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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and closed-world scope, so the safety profile is fully covered elsewhere. The description contributes only the single-record framing, with nothing about missing records or return shape. That is a modest addition over the annotations, hence a 3.

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?

A single front-loaded sentence with zero filler. It is efficient, though its extreme terseness leaves little room for the routing and behavioral content an agent could use.

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 one-parameter read with full annotation coverage and no output schema to explain, the minimal description is close to sufficient. It omits what happens when the id does not exist and how the result relates to the payment list, leaving small but real gaps.

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?

There is exactly one required parameter at 100% schema description coverage, so the schema already fully documents it. The description's 'by id' matches but adds no format, source, or validation detail beyond the schema.

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 names a specific verb and resource (read an invoice_payment) and adds the singular scope 'one ... by id', which distinguishes it from the sibling invoice_payment_list. It never names that sibling explicitly, so the differentiation is implied rather than stated.

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?

'Read one ... by id' implies the lookup-by-identifier case, but the description never states when to prefer it over invoice_payment_list or invoice_search, nor any prerequisites or failure behavior for an unknown id.

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