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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds genuinely new information the annotations lack: a per-record credit cost ('1 point per returned record'), which is material to an agent budgeting a call with max_items up to 500. It does not cover pagination behavior, keeping it below 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?

Two short sentences, zero filler, with the core capability front-loaded and the billing note trailing. Every clause carries information.

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 usefully sketches what a record contains (title, price, condition, seller summary) and discloses cost per record. For a 9-parameter search tool whose annotations cover the safety profile, this is close to sufficient, though pagination and result-volume behavior remain 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% across all 9 parameters, including enum label expansions and defaults for max_items and start_page, so the schema carries parameter meaning. The description lists filter dimensions only implicitly ('title, price, condition'), adding no syntax or default detail beyond the schema — the baseline 3 for high coverage.

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 (search active eBay listings) plus the returned fields (title, price, condition, seller summary), which lets an agent distinguish it from the singular run_ebay_item or the seller-oriented run_ebay_seller_items siblings. It does not explicitly name a sibling alternative, so it stops short of a 5.

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 word 'active' implies exclusion of ended/sold listings, but there is no explicit when-to-use, when-not-to-use, or alternative-tool guidance. Nothing tells the agent when run_ebay_item or run_ebay_product would be preferable.

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