capture_screen

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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: 'all' stitches every screen together, and the default max_dimension is chosen to balance legibility against token cost. It omits permissions, error cases, and rate limits, which keeps it short of a 5.

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?

One front-loaded sentence states the action and return type, followed by a compact Args block with no filler. Every line supplies information an agent needs to call the tool correctly.

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 correctly states the return is an image, and all three parameters are fully explained despite zero schema coverage. It leaves minor gaps such as behavior on multi-monitor failure or permission requirements, but nothing that would cause a mis-call.

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%, so the description carries the full burden and does: monitor accepts 'primary', 'all' (with stitch semantics), or a number where 1 = leftmost; max_dimension is bounded 256-4096 with a reason to change it; image_format lists jpeg vs png with a tradeoff for each. This adds real meaning that the bare schema (no enums, no descriptions) cannot convey.

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 ('Take one screenshot of a monitor and return it as an image') with the delivery format included. It also cross-references the sibling list_monitors as the way to discover monitor values, so an agent can distinguish the two tools 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 concrete conditional guidance: raise max_dimension only when small text is unreadable, and choose png over jpeg when small text needs to be crisper. It does not state explicit exclusions (e.g. when not to screenshot vs use list_monitors), but for a single-purpose capture tool the parameter-level guidance is clear.

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