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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is fully covered elsewhere. The description adds genuinely new behavioral facts — a hard cap of 8 screens per search and the shape of each result (summary, thumbnail, full-screenshot link) — but says nothing about why pagination stops at offset 16 or what happens on empty results.

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, both front-loaded: the first establishes what is searchable, the second establishes why to use it and what comes back. The long enumeration of sectors and screen kinds is dense but earns its place by showing the breadth of the index.

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 compensates by stating the return payload and result cap. For a 7-parameter, fully-optional search tool this is close to complete; only the interaction between the free-text query and the type/state/sector filters is left unstated.

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% and all 7 parameters carry their own descriptions with examples and enum values, so the baseline of 3 applies. The description adds no parameter-specific guidance, such as how query and type interact or how offset should be stepped given the 8-result cap.

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 opens with a specific verb and resource ("Find real examples of website screens captured from live sites") and enumerates the screen categories, states and devices covered, so the agent knows exactly what universe of results to expect. It does not explicitly distinguish itself from get_screen or list_screen_types, leaving that differentiation to the schema's cross-reference.

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?

It gives concrete use cases ("UI and UX inspiration, design references, competitor research, or 'show me how other sites do X'"), which is clear context for when to reach for this tool. It stops short of naming when NOT to use it or pointing to get_screen/list_screen_types as alternatives.

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