screenshot

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

Annotations already declare readOnly, non-destructive, non-idempotent and closed-world, so the safety profile is covered. The description adds genuinely new context: the result is MCP image content, and that image data is untrusted page evidence (a prompt-injection warning). It stops short of explaining what 'bounded' constrains or how full_page interacts with it.

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, no filler, purpose front-loaded and the trust caveat placed immediately after. Every word 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?

For a 4-parameter tool with no output schema and no parameter documentation, the description is too thin. It omits what 'bounded' means, how to target a selector or request a full-page capture, and when this is preferable to the page-snapshot sibling.

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 0% across 4 parameters, so the description must carry the load and does not. selector, format, full_page and session_id are never mentioned, and the ambiguous word 'bounded' is not tied to the full_page flag it presumably opposes.

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: 'Capture a bounded screenshot as an MCP image.' An agent knows exactly what the tool produces. It does not, however, differentiate itself from the adjacent get_page_snapshot/verify_page siblings, which also return page-derived evidence.

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?

No when-to-use guidance and no alternatives named. With get_page_snapshot and verify_page in the sibling list, the agent is left to guess whether a screenshot or a snapshot is the right evidence-gathering call.

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