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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds two useful behavioral facts beyond that: results carry only compact metadata, and the tool supports paging through the library. It stops short of describing ordering defaults or page-size behavior, which the schema covers instead.

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 sentences with no filler, and the primary purpose is front-loaded. However, the second sentence packs three clauses (browse, filter alternative, view alternative) into one semicolon chain, which is slightly dense for the amount of routing information it carries.

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 is a simple read-only list with three optional, fully documented parameters, an output schema, and annotations covering the safety profile. The description covers what to call it for, what it returns at a high level, and where to go instead, so nothing an agent needs 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 coverage is 100% and each parameter's enum, bounds and defaults are documented in the schema, so the description is not required to compensate. It only hints at paging semantics via 'page through the library' and adds no sort or cursor detail beyond what the schema already states, so the 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 (List) plus the resource and scope (the signed-in user's cloud screenshots) and notes the payload is compact metadata. It explicitly names the two sibling tools it is not, so an agent can distinguish it from search_screenshots and get_screenshot without opening a schema.

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?

Gives explicit use cases (browse recent screenshots, page through the library) and routes filtering to search_screenshots and single-item viewing to get_screenshot. The when-to-use versus alternatives split is fully spelled out.

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