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

Annotations already declare readOnlyHint=true, so safety is covered; the description adds the underlying endpoint (GET /credit_notes/{id}), which usefully signals a direct read with no side effects. It says nothing about 404/error behavior, auth requirements, or rate limits, so it adds only modest context beyond the 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 short sentences, front-loaded with the action and resource, zero filler. The endpoint mapping is compact and 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 single-parameter read tool with a fully described schema and a readOnly annotation, this is nearly complete. The only minor gap is that no output schema exists and the description does not hint at the shape of the returned credit note.

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% for the single `id` parameter, so the schema already fully documents it. The description's 'by id' adds no format, source, or constraint detail beyond what the schema states.

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 ('Fetch a single credit note') with an explicit scope qualifier ('by id') that separates it from quaderno_list_credit_notes. It does not name the sibling outright, but the singular/ID framing makes the distinction inferable.

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?

Usage is only implied: fetch one record when you have its id. There is no explicit statement of when to prefer this over quaderno_list_credit_notes or quaderno_request, and no prerequisites or failure conditions are given.

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