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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety profile. The description adds real signal beyond that — data is 'public' (no auth needed) and comes from a 'rendered product page', telling the agent the payload derives from a live page render. It stops short of describing pagination or failure modes, but an output schema exists to carry the return shape.

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 sentences, zero waste, with the capability stated first and the routing instruction second. Nothing is padded or redundant.

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, everything needed is present: what it returns (product details), how to obtain the required URL (via the search/category siblings), the safe-read annotation profile, and an output schema for the return shape.

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% for the single URL parameter and the schema already states 'Canonical Otto.de product URL returned by otto-search'. The description only implies the same URL source, adding no format or constraint detail beyond the schema, so baselining at 3 is right.

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 ('Fetch'), resource ('public Otto.de product details') and source ('its rendered product page'). It also names the sibling tools (otto_search, otto_categories) so the agent can place it correctly in the toolset without opening any 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?

Explicitly instructs the agent to use otto_search or otto_categories to find a product before requesting its detail, giving both the prerequisite and the alternative tools. Nothing about when to reach for this tool 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.