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

Annotations only declare readOnlyHint=true, and the description goes beyond that by disclosing the return shape (a pointer, not the body), the error behavior for unknown slugs, and the caller's next step. Useful added context, though it says nothing about pagination, rate limits, or auth needs.

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?

Labeled WHAT/USE/NEXT/EXCLUSION fragments keep it front-loaded and scannable, and every clause carries information an agent needs for selection or chaining. Zero filler.

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 single-lookup tool with a full schema and an output schema, the description supplies the remaining decision-critical pieces: when to choose it, what happens on a miss, and which tool to call next for the fulltext. Nothing needed to call it correctly is missing.

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 description coverage is 100%, so slug provenance and locale semantics (prefix rules, default de, non-effect on prices/legal names) are already fully documented in the schema. The description's 'REQUIRED slug from list_ratgeber' restates what the schema already says and adds nothing for locale, so the baseline 3 applies.

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?

Opens with a specific verb and resource: 'Returns one Ratgeber page pointer (canonicalUrl /ratgeber/{slug})'. It also explicitly delimits itself against the sibling list_ratgeber ('DOES NOT return the article body here'), so an agent can distinguish it without opening either schema.

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 use condition ('USE when the slug is already known'), an explicit counter-condition with the named alternative ('Prefer list_ratgeber when the slug is unknown'), and a defined failure path ('Unknown slug → unknown_ratgeber (+ hub URL)'). Nothing about routing is left to inference.

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