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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), and the description adds useful behavior beyond that: the payload is full Markdown text, written in Swedish, and includes Skatteverket sources plus a check date. It does not mention document size or any truncation limits, which matters for a full-text read.

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?

Three short sentences, zero filler, with the return value stated first and the selection hint last. Every clause carries distinct information (payload, slug source, content options, language, provenance, usage).

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 no output schema, the description correctly explains the return value as full Markdown text and notes language and source attribution. The only real gap is document length or response size, which an agent reading full guides would want to anticipate.

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% and the single parameter is an enum with its own description, so the baseline is 3. The description earns above baseline by explaining what each enum value actually contains (K4 avsnitt D step by step, genomsnittsmetoden with worked examples, tools comparison), which helps the agent pick the right slug.

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?

States a specific verb and resource ('Return the full Markdown text of one guide by slug') and then enumerates the three guide types it can return, so an agent knows exactly what comes back. It also points to the sibling list_guides as the source of slugs, separating it from the listing tool.

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?

'Use this to answer K4 questions from source text' gives a clear selection rule, and '(see list_guides)' tells the agent the prerequisite step before calling. It stops short of stating when not to use it (e.g. versus get_crypto_tax_tool), so it is clear context rather than full routing guidance.

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