get_viewport_image

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

With no annotations, the description carries the full burden. It does disclose the return form ('data URI'), which is useful, but it does not state whether this is a read-only operation, what the timeout parameter controls, whether it requires an active viewport to exist, or how it behaves if the named viewport is unavailable. The 'compatibility wrapper' phrasing hints at a thin passthrough but gives no concrete behavioral detail.

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 short sentence with no filler. The key output characteristic (data URI) is front-loaded. While it is terse to the point of under-specification, it earns its place by establishing the tool's essential purpose.

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?

Although an output schema exists, the description is too thin for a tool with three optional parameters and numerous viewport-related siblings. It doesn't explain how to select a viewport, what formats are supported, or whether this is a legacy alias to avoid. The 'compatibility wrapper' context raises more questions than it answers.

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% and the description mentions none of the three parameters. The parameter names (timeout, image_format, viewport_name) are self-explanatory at a basic level, but there's no guidance on accepted image_format values, how viewport_name is resolved, or what timeout units are used. The description fails to compensate for the schema's lack of documentation.

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?

Clear verb 'returning' and resource 'viewport' make the basic function evident. The phrase 'data URI' specifies the output format. However, it doesn't distinguish from the sibling 'capture_viewport', so the 'compatibility wrapper' framing is the only differentiator and its meaning is left vague.

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 or when-not-to-use guidance is provided. The term 'compatibility wrapper' suggests legacy usage, but there is no explicit recommendation against using it or a pointer to capture_viewport as an alternative. An agent cannot determine from the description whether to call this tool or one of the other viewport-related siblings.

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