screenshot

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does not mention output format, image encoding (base64 vs file path), what happens if no tab is active, permission requirements, or other behavioral traits. The description only restates core function without additional transparency beyond parameter names.

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 concise sentence with no wasted words. It's appropriately short for a two-parameter tool. However, given the thin information content, one might argue it does too little, but for the information it conveys, it is efficiently structured and front-loaded with the primary action.

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?

This is a capture/mutation tool with no annotations and no output schema. The description doesn't explain what the output looks like (image format, where it's stored), which is a significant gap for a tool whose entire purpose is producing output. Given the low complexity (2 optional params), it's understandable but still under-specified for an agent needing to use the returned data.

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 100%, so the schema already documents both parameters (tab_id and full_page). The description references tab_id but adds no detail beyond the schema's own descriptions. Baseline 3 applies since schema does the heavy lifting and the description doesn't add extra param meaning.

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 'Capture a screenshot of the active tab (or tab_id)' uses a clear verb (Capture) and resource (screenshot of active tab). It distinguishes from siblings like snapshot (likely DOM/AX tree snapshot) and clarifies the tab scoping. Could more explicitly differentiate from 'snapshot' but the active-tab phrasing is reasonably distinct.

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 it captures the active tab but does not state when to use it versus 'snapshot' or the browser_exec/eval_js alternatives for capturing content. No explicit when-to-use or when-not-to-use guidance, no mention of prerequisites like needing a page loaded. Minimal context for choosing between screenshot and snapshot.

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