capture_webpage_tool

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

No annotations are provided, so the description carries the full burden. It mentions that the browser launches on first use and stays running, which is helpful. However, it doesn't disclose potential behavioral traits like memory usage, rate limits, or failure modes (e.g., if the page times out).

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 well-structured: a concise introductory paragraph, followed by bullet points for each parameter. It is front-loaded with the main purpose. However, the parameter descriptions could be slightly more concise, and the overall length is justified by the lack of schema descriptions.

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 no output schema, the description correctly states it returns an Image. It covers all 6 parameters, usage context (localhost, web apps), and behavioral note (browser staying running). The tool's purpose and parameters are fully explained, making it complete for agent invocation.

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 must compensate. It provides a detailed explanation for each parameter, including defaults and example values (e.g., 'url: The URL to capture (e.g., "http://localhost:3000")') and clarifies the purpose of each. This adds significant value beyond the schema.

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 the tool captures a screenshot of a web page using a headless browser. It specifies the resource (web page) and action (capture screenshot), and distinguishes from siblings like capture_screen (likely whole screen) and capture_window_tool. The mention of local dev servers adds specificity.

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 explicitly says 'Useful for capturing local dev servers (localhost), web apps, or any URL,' providing clear usage context. It doesn't explicitly state when not to use or alternatives, but the context implies use for web pages, and siblings are listed separately.

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