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 real value beyond that by stating the call is free (no credits consumed), that it is a mandatory precursor to segment writing, and what the payload contains. The version stamp is minor noise rather than behavioral context.

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?

Dense but front-loaded: the action and its contents come before the sibling routing and before the trailing "Firmafakta 1.8.87" stamp. The version string adds little for an agent that already has firmafakta_version as a sibling, a small deduction from an otherwise tight two-sentence block.

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, yet the description still summarizes them usefully. For a zero-parameter, read-only discovery tool this is complete: the agent knows when to call it, that it is free, and what it will get 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?

Zero parameters, so the baseline is 4; there is nothing for the description to disambiguate. It does add value by describing what the call surfaces, which helps the agent decide to invoke it rather than a sibling.

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?

Names a specific verb ("returns") and enumerates the exact resources delivered: segment language with examples, filter fields with operators and code tables, returned fields with plan requirements, plan, credits, prices and rate limits. It is unambiguously a metadata/discovery tool and is explicitly differentiated from firmafakta_find_codes and firmafakta_version.

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?

Gives an explicit ordering instruction ("Call this first, before writing a segment") plus two routing exclusions with the sibling to use instead for place/industry codes and for release notes. Both when-to-use and when-not-to-use are covered.

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