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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds the useful scoping fact that the letter must have been previously sent, but says nothing about what the returned status comprises, whether results are cached/live, or what happens when the id is unknown.

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 well-formed sentence with the scope constraint front-loaded before the lookup key. Nothing is redundant or padded.

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 this is close to adequate, and annotations cover the safety profile. However, with no output schema the description should have sketched what the status response contains (e.g. delivery state, timestamps) and what an invalid or unknown id yields; that information is absent.

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 schema has 0% description coverage for the single required `id` field, so the description must carry the meaning. It only says "ud fra dets id" (based on its id), which identifies the id as the letter's own identifier rather than an order id, but adds no format, source, or example. This is thin compensation for the coverage 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?

The description pairs a specific verb with a specific resource: "Viser status for et tidligere sendt brev" (shows status for a previously sent letter). The qualifier "tidligere sendt" separates it from send_letter and list_letters, but no sibling is named explicitly, so differentiation is only partial.

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 phrase "tidligere sendt brev" implies a precondition (the letter must already have been sent) and thus steers agents away from using it for unsent orders, but this is inferred rather than stated. There is no explicit when-not guidance and no mention of get_order_status or list_letters as alternatives for other lookup needs.

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