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

Annotations already cover read-only, idempotent, non-destructive, open-world semantics, so the bar is lower — yet the description still adds real value by disclosing the 5-minute result cache and the consequent staleness on live auctions. It stops short of saying whether the full bid list is returned or truncated for high-volume listings.

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-loads what is returned, then the interpretation rule for ended auctions, then the ID source, then the caching caveat — four tight sentences with no filler. Readable without the 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?

There is no output schema, so the description carries return-value disclosure and does so enumerating amount, quantity, bidder username, timestamp and bid type. Combined with the cache caveat and the winning-bid interpretation, an agent has everything needed to call and interpret it.

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 site, _apiKey and listing_id are already documented including enum semantics and currency behavior. The description contributes only the provenance hint that listing_id comes from ebid_search, without adding format or edge-case details, so 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?

States a specific verb and resource ("Bid history for one eBid.net listing") and names the upstream API (GetListingBids). It is clearly distinguishable from sibling tools ebid_listing (single listing detail) and ebid_search (finding listings), since this one returns the bid set for a known listing.

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 routes the agent to ebid_search for obtaining ListingIDs, which is the key prerequisite for calling this tool. It does not, however, state when not to use it (e.g. a live auction where sub-5-minute freshness is required), so it falls short of full alternative/exclusion guidance.

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