Search eBay listings

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

The description adds value beyond annotations: it explicitly states 'Read-only: this never bids, adds to a cart, or places an order,' which is more specific than the generic readOnlyHint annotation. It also discloses the output fields (title, price, shipping, etc.), which is a behavioral trait not covered by annotations or schema. No contradiction; this enhances transparency.

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?

The description is two sentences: the first states the core action and filters, the second clarifies read-only behavior. It is front-loaded with the key information and contains zero fluff. Every word serves a purpose, making it highly efficient.

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?

The tool has 9 parameters, but the schema fully documents them, and the description explains what the tool returns and its read-only nature. It lacks mention of pagination or how to interpret structured results, but given the schema coverage and the read-only clarification, the description is complete enough for an agent to invoke correctly. The openWorldHint is not elaborated, but that's acceptable since it's a hint rather than a requirement.

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 each parameter has detailed descriptions. The tool description itself only gives a high-level overview ('optional price, condition, buying-format, and shipping filters'), adding marginal value beyond the schema. However, it does connect the filters to the search intent, which aligns with the baseline of 3. No specific parameter semantics beyond what schema already provides.

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?

The description is specific and action-oriented: 'Search eBay for listings matching a keyword query' with optional filters and a clear list of returned fields (title, price, shipping, landed total, seller rating, link). It distinguishes from siblings by focusing on search behavior, and the read-only note further clarifies scope. The verb-resource pair is unambiguous and distinct from check_ebay_connection, get_listing_details, and find_deals.

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?

The description provides some usage context (search for listings, optional filters) but does not explicitly tell when to use this tool over siblings like get_listing_details or find_deals. It also includes a helpful tip in the schema about using 'ending_soonest' with auctions, but that guidance is embedded in the schema description, not the main description. No clear when-not or alternative tool mention, so it is adequate but not explicit.

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