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

The readOnlyHint and openWorldHint annotations already establish that this is a safe, self-contained read against Postlys's own data. The description adds that prices are 'aktuelle' (current) and covers two letter classes, which is modest extra context. It says nothing about currency, whether prices include VAT, caching/freshness guarantees, or rate limits.

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?

A single sentence with no filler, and the resource and its scope are front-loaded. Nothing in it is redundant with the title beyond unavoidable overlap.

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 zero-parameter tool this is nearly sufficient, but with no output schema the description should say something about the shape of the return value — a price list per letter type, currency, or validity period. As written, an agent knows what the tool fetches but not what it receives back.

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?

The tool takes zero parameters, so the baseline of 4 applies; there is nothing for the description to disambiguate. The mention of two letter categories ('almindelige og rekommanderede') is informative about coverage but is not mapped to any input, since none exist.

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?

The description states a specific verb and resource ('Henter ... aktuelle priser') plus the scope of what is priced ('almindelige og rekommanderede breve'). This clearly separates it from the sibling tools, which all deal with orders, letters, or balance rather than prices. It stops short of naming a sibling outright, but no ambiguity remains.

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: an agent can infer this is the price-lookup step before calling create_letter_order or send_letter, since every sibling is order- or letter-oriented. There is no explicit statement of when to call it, no prerequisites, and no mention of alternatives or when not to use it.

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