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

Annotations already declare readOnly/idempotent/non-destructive and openWorldHint=false, and the description stays consistent with a closed-domain read. It adds real behavioral context beyond them: the response has three parts (siteSearchUrl, browse, products), products come only from partner shops that permit redistribution and may be empty, and links must be passed through unchanged.

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?

Well front-loaded: purpose first, then when to use, then what is returned, then the link-passing rule. The German and English blocks are largely duplicative, which costs some length, but each block is dense and no sentence is 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?

With an output schema, full parameter coverage and annotations present, the description supplies what the structured fields cannot: trigger conditions, the three-part return shape, the empty-products caveat and the instruction not to rewrite URLs. Only pagination/result-count behavior and the relationship to sibling tools are unaddressed.

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 baseline is 3; the schema already documents brand, limit, query, price bounds and language. The description only adds one actionable hint beyond it (set language="en" for English pages) and otherwise refers generically to "Filtern", so it does not materially extend parameter meaning.

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+resource: a price comparison for Stromspeicher across many shops on wospeicher.de, with filters, comparisons and buying guides. An agent can tell it is the price/offer lookup tool rather than a page resolver (find_pages) or a single-product lookup (lookup_product), though siblings are never named explicitly.

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 concrete trigger conditions: use when the user asks about price, offer, "guenstig", "wo kaufen", or a specific Stromspeicher. It does not state when NOT to use it or name find_pages/lookup_product as alternatives for adjacent intents, so routing between siblings is left partly to inference.

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