get_marks

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true and openWorldHint=false, so the safety profile is covered without the description. The description adds only marginal value beyond that: 'non-destructive' restates destructiveHint=false, while 'opaque marks_id mapping' is genuinely new but leaves open whether marks_id expires, is reusable, or how it relates to snapshot_id.

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?

A single front-loaded sentence with no filler, and the outcome (marks_id) is stated at the end. It is efficient but arguably too terse for an 11-parameter tool, so the economy is not fully earned.

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 an 11-parameter tool with a nested region object, 18% schema coverage, and no output schema, the description is far too thin. It does not explain the marks overlay contents, the marks_id lifecycle, or any of the rendering parameters, so an agent cannot confidently invoke it beyond the required app argument.

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 only 18% (just app and coordinate_space are documented), leaving 9 of 11 parameters undocumented. The description says nothing about zoom, scale, region, quality, format, ocr_id, snapshot_id, max_dimension, or include_elements, and 'bound target screenshot' only loosely implies how app binds the target. Description fails to compensate for the large coverage gap.

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 (render) and resource (numbered Set-of-Marks overlay) plus the returned artifact (marks_id), which is more precise than a generic 'get'. It does not differentiate itself from siblings such as click_mark or ocr, which are the natural upstream/downstream partners, so an agent must infer the relationship.

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?

There is no explicit when-to-use guidance and no mention of alternatives. The obvious workflow (call get_marks, then click_mark with the resulting marks_id) is never stated, nor is it explained when to prefer this over screenshot or ocr. Usage is only implied by the noun 'marks_id'.

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