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

Annotations already declare readOnlyHint and openWorldHint. The description adds real behavioral context beyond them: the response includes a complete raw spec table grouped by section, and critically that Chrono24 has no lookup by numeric id alone, constraining how the path must be obtained.

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?

Front-loaded with the purpose, then the input-source constraint. The field enumeration is long, and since an output schema exists it is somewhat redundant, but it is readable and each part serves a purpose.

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 present, return values need not be spelled out. The description covers purpose, the source of the single input, and the no-numeric-id constraint, leaving little an agent would need to call it correctly.

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 0%, so the description carries the full burden for the single Path parameter. It explains exactly what Path is (the listing URL from a chrono24_search result) and rules out the numeric-id alternative, compensating well for the undocumented schema.

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 ('One Chrono24 watch listing's full detail') and enumerates the concrete fields returned (brand, model, reference number, price, condition, movement, etc.), making it clearly distinguishable from sibling tools like chrono24_search or chrono24_dealer.

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?

It tells the agent where the required input comes from ('path is the listing url from a chrono24_search result'), which implies the correct call order. There is no explicit when-not guidance, but the context is clear.

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