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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real behavioral context beyond them: a 5-minute result cache and the warning to treat the current bid as a lower bound near auction close. It does not cover failure behavior for an invalid slug or what is returned when display_id is omitted for a multi-lot auction, so it stops short of a 5.

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?

Four sentences, each carrying distinct load: the return payload, the slug provenance, the display_id rule, and the cache caveat. Detail list is front-loaded and there is no redundant restatement of the annotations or schema.

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 takes on the burden of describing return values and does so by enumerating the fields. Combined with the freshness caveat and source domain, an agent has everything needed to call it and interpret the result 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 100%, so baseline is 3, and the description still adds meaning the schema does not: auction_slug is the URL segment after /en/a/, and display_id should be omitted for single-lot auctions. That is a genuine supplement rather than a restatement.

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 ('Full detail for one Troostwijk lot within its auction') and enumerates exactly what detail is returned: auction description, current/final bid, sale outcome, bid count, location. That enumeration distinguishes it from troostwijk_search_lots and troostwijk_sold_comps, which are named as the source of the slug.

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?

Explains where auction_slug comes from (the part after /en/a/ in a search or sold-comps result URL) and when to pass display_id (multi-lot) versus omit it (single-lot). Clear usage context, though it does not explicitly exclude any scenario or name a sibling as the fallback for a different task.

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