zen_full_page_screenshot

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

With no annotations, the description carries the full burden and discloses the 'scroll-and-stitch' technique, the 30-viewport height limit, and that it returns a single PNG data URL. However, it does not mention whether scrolling is involved, if the page needs to be fully loaded, or any performance implications, leaving gaps in behavioral transparency.

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?

The description is a single sentence (plus a clarifying clause) that provides all essential information without redundancy. Every word contributes meaning, making it highly concise and well-structured.

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?

Given the simple tool with one parameter and no output schema, the description covers the core purpose, technique, limit, and output format. However, it lacks details about parameter usage and behavioral nuances (e.g., whether it scrolls the page or waits for loading), leaving some gaps for a complete understanding.

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?

The input schema has one optional parameter (tab_id) with no description (0% coverage). The description does not mention this parameter at all, so it adds no meaning beyond the schema. The agent has no guidance on what the parameter does or how to use it.

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 clearly states it captures a 'scroll-and-stitch screenshot covering the full document height' and returns a PNG data URL. It explicitly distinguishes from viewport-only screenshots by specifying 'full document height' and includes a height limit of 30 viewports. This provides a specific verb+resource combination, easily differentiating it from sibling tools like zen_screenshot and zen_element_screenshot.

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?

The description implies usage for full-page capture but does not explicitly state when to use this tool versus alternatives like zen_screenshot (viewport-only) or zen_element_screenshot. There is no direct comparison or exclusion criteria, so the guidance is only implied through the phrase 'full document height'.

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