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 genuinely useful behavior: the returned field set matches list_payslips (compensating for the absent output schema) and a tenant-scoping rule that a foreign id is an error. It stops short of describing the not-found error explicitly.

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 core action and followed by the return-shape and error-scope facts. No filler; every clause adds information.

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 tool with no output schema, the description covers return shape (same as list_payslips) and the tenancy error condition. It is nearly complete; the only gap is the precise not-found error semantics and any pagination/adjacent concerns, which do not apply here.

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 0% for the single 'id' parameter, so the description carries the burden. It partially compensates by declaring the id is scoped to this business's payslip (an out-of-scope id is an error), but gives no format or type detail, which is typical for an id field but still a gap.

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 ('One payslip by id') and explicitly contrasts with the sibling list_payslips by noting field parity. An agent can distinguish single-fetch from list without opening the schema, though it does not distinguish itself from the other payslip siblings (save_payslip, delete_payslips).

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: 'one payslip by id' suggests a single-record fetch versus list_payslips, but there is no explicit when-to-use/when-not guidance or named alternative beyond the implicit contrast. Adequate but leaves routing to inference.

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