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 descriptive bar is lower. The description adds the endpoint mapping but says nothing about behavior on an unknown id or whether embedded resources change the payload; adequate but not rich.

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 verb and scope, with the endpoint detail appended. No filler or restated title boilerplate.

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 single-resource read with full schema coverage and no output schema, the description is nearly complete — an agent knows exactly what to call and with what. Only the sibling routing and non-found behavior are unstated, which are minor 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?

Schema description coverage is 100%, with both voucher_id and embed fully documented in the schema, so the baseline is 3. The description adds only 'by id' and no extra syntax or semantics beyond what the schema already provides.

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 (Fetch) and resource (a single voucher/receipt) scoped by id, and adds the underlying endpoint GET /Voucher/{voucherId}. The singular 'single voucher' cleanly distinguishes it from the sibling sevdesk_list_vouchers without needing to name it.

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: 'by id' tells the agent it needs a known voucher id, but there is no explicit when-to-use/when-not framing and no mention of alternatives like sevdesk_list_vouchers for lookup. Minimum viable guidance.

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