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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the description's added value is the real-browser rendering behavior, the video-frame special case, and an explicit monthly allowance/rate-limit note for free keys. That is meaningful context beyond the structured fields, though it omits failure behavior (timeouts, blocked pages, auth errors).

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?

Three short sentences, zero filler, with the core behavior front-loaded and the quota pointer placed last where it belongs. Every sentence carries distinct information.

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?

With no output schema, the description correctly takes on the burden of describing return values (screenshot, rendered text, video frames), which is the key thing an agent needs. It could go slightly further on error/empty-result behavior for a read-only browsing tool.

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 explains `target`, `view`, and `full_page` fully. The description adds no syntax or format detail beyond what the schema provides, so baseline 3 applies.

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?

Specific verb+resource: 'Load a URL in a real browser' and it names the two artifacts returned (screenshot + rendered text), plus the video variant. It doesn't explicitly distinguish itself from siblings like `read` (text extraction) or `perceive`, so the differentiation is implied rather than stated.

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?

It gives one actionable routing hint (call `senses` to check remaining allowance) and notes the video-URL case, but offers no guidance on when to choose this over `read`/`perceive`/`hear` or what happens for non-HTML targets.

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