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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful scope information (segments saved on firmafakta.se, called 'Sparade urval'), but it says nothing about behavior on a non-matching name/id, on ambiguous names, or on supplying both parameters.

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 no-argument case, with no filler. The phrasing 'With one: the segment's expression' is slightly telegraphic and leaves the reader to infer 'one of name or id'.

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?

An output schema exists, so return values need not be explained, and the core list-vs-fetch behavior is covered. However, the undefined term 'expression' and the unaddressed both-parameters and no-match cases leave real gaps for a tool with two optional parameters.

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 coverage is 100%, so the baseline would be 3, but the description goes beyond the schema by explaining the semantic effect of parameter presence: either parameter switches the tool from list mode to expression mode. It still does not clarify precedence when both are provided.

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 names a concrete resource (the account's saved segments) and two distinct behaviors: listing them when no argument is given, and returning a segment's expression when one is. That is specific enough to separate it from firmafakta_fetch or firmafakta_lookup, though it never explicitly contrasts itself with those siblings.

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?

It gives an explicit conditional rule for choosing between the tool's two modes: no name/id means list, one name/id means fetch the expression. What is missing is any guidance on when to prefer a sibling tool or what to do if both parameters are supplied.

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