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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description goes beyond that by disclosing the response payload (line items, modifiers, discounts, taxes, payments) and mapping to the underlying API route, which helps the agent anticipate the result shape given there is no output schema.

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 tightly packed sentences: the resource and payload contents come first, the API mapping second. No filler, and the example is embedded inline rather than in a separate clause.

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?

With one required parameter and no output schema, the description supplies what the schema cannot: an outline of the returned receipt contents and the endpoint it maps to. It is nearly complete; only a note on behavior for an invalid/unknown receipt number is missing.

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% and the single parameter is fully documented inline, so the schema carries the load. The description only restates the receipt-number format with the same example already in the schema, adding no additional constraint or syntax detail. Baseline 3 applies.

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?

Specific verb (Fetch) plus a single, well-defined resource (a receipt by receipt number), with a concrete example format. The word 'single' cleanly distinguishes it from the sibling loyverse_list_receipts, and it even enumerates the payload contents so the agent knows the depth of the fetch.

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 implied by 'fetch a single receipt by its receipt number', but the description never explicitly says when to prefer this over loyverse_list_receipts or what happens if the number is unknown. No prerequisites or error conditions are stated.

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