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

Annotations already cover read-only, idempotent and open-world status, and the description adds genuinely non-obvious behavior: a 5-minute result cache that makes current bids a lower bound near auction close, plus the exact fields returned (bid price, bid count, buy-now, end time, URL).

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?

Three sentences, front-loaded with purpose then return shape then the cache caveat. Slightly dense but every sentence contributes; the trailing attribution sentence ('Sourced from the shopgoodwill.com search API') is the only near-filler.

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?

No output schema exists, yet the description enumerates the returned fields, and it discloses the freshness limitation that would otherwise mislead an agent bidding near close. Nothing essential to correct invocation is missing.

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 all seven parameters are documented in the schema itself; the description adds no syntax or format detail beyond it. Baseline 3 applies when the schema carries the full parameter burden.

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 auctions on shopgoodwill.com') plus the inventory scope (cameras, jewelry, electronics, etc.), which cleanly separates it from the sibling shopgoodwill_sold_search by restricting to live listings.

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' implicitly routes an agent away from the sold-search sibling, and the cache warning tells the caller when results are appropriate for bidding decisions. However, no sibling is named explicitly, so an agent must infer the active-vs-sold split.

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