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

readOnlyHint=true already tells the agent this is a safe, non-mutating read, so the description's burden is lighter. It adds that this maps to the backend endpoint GET /Voucher/{voucherId}, which is useful provenance, but says nothing about error behavior for invalid ids or what the returned object contains.

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, zero filler, with the core action front-loaded ahead of the API endpoint detail. Nothing here is redundant.

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 two-parameter read tool with no output schema, the description is minimally sufficient: it identifies the lookup key and the operation. It does not hint at the shape of the returned voucher or the referential error case, which keeps it at adequate rather than complete.

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 description coverage is 100%, with both voucher_id and embed documented in the schema itself, so the baseline is 3. The description adds no syntax, format, or usage notes for either parameter, leaving the schema to carry the explanation entirely.

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 voucher (receipt) by id') and the singular framing implicitly differentiates it from the sibling sevdesk_list_vouchers. It also clarifies that 'voucher' means a receipt, which helps an agent map domain terminology. No sibling is explicitly named, so it falls just short of a 5.

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 gives no when-to-use or when-not-to-use guidance and never references the alternative sevdesk_list_vouchers for broader retrieval. An agent can infer the direct-lookup intent from 'by id', but nothing is stated explicitly.

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