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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds useful behavioral context: the operation compares against a captured baseline, output contains identity/fulfillment fields, and re-running watchlist_add resets the baseline. This goes beyond the structured annotations without contradicting them.

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 with no filler: the first states the core purpose and output, the second covers output details, and the third gives usage phrasing plus a baseline-reset note. It is front-loaded and every sentence earns its place.

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?

Given the tool's high complexity (24 parameters, no output schema), the description is incomplete. It explains the baseline concept and reset path, but leaves the many filtering parameters and the full return shape undocumented, so an agent would likely need additional inference or tool output exploration to use it 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 description coverage is only 25%, with 18 of 24 parameters having no description. The description mentions high-level concepts like new sellers and score moves but provides no guidance on the many filter parameters (price ranges, score deltas, seller counts, fulfillment percentages, etc.), so it does not compensate for the schema's gaps.

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 clearly states the verb ('Show what changed') and the resource ('a saved tracking list versus its captured baseline'), and enumerates the kinds of changes (new sellers, sourcing-score moves) plus the per-ASIN identity and fulfillment data. It is specific enough to distinguish from list/stat tools, but it does not explicitly differentiate itself from the similarly named sibling watchlist_delta.

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 concrete user-phrase triggers ('what changed on <list>', 'any updates on my watchlist', 'new sellers on the ASINs I track'), which is clear usage guidance. However, it does not state when to use an alternative tool instead, such as watchlist_list or watchlist_delta.

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