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

Goes well beyond the annotations, which only say readOnlyHint=false and idempotentHint=true. It discloses the privacy model (typed values are secret in screen_look and shown as dots), the side-effect scope ('nothing is recorded meanwhile'), the exact return contract (done:true/false) and the cancel/timeout semantics. This is rich behavioral context an agent could not get elsewhere.

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?

Front-loaded with the core action and only includes sentences that add behavior (security, return values, failure handling). The trailing parameter line is a slightly bolted-on appendix but is compact and useful.

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 supplies the return contract and side-effect profile for a sensitive handover operation. The only real gap is the undocumented required 'reason' and the 'ref'/'seconds' parameters, which leaves the description not quite complete for a 6-parameter 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 0% across 6 parameters, so the description must carry the load. It explains only three (response_detail with its enum values, fields as dotted paths, cursor as next page) and leaves the required 'reason' plus 'ref' and 'seconds' entirely undocumented, so the agent cannot fully infer correct argument usage.

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?

States a specific verb (hand over) and resource (the open page) with concrete examples of the triggering situations (sign in, enter a code, accept a prompt). However, it does not differentiate itself from the very similar sibling 'screen_login', which an agent could easily confuse with this tool.

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?

Gives clear context ('something only they should do') and a negative case ('in one of their own apps they simply type it themselves'), plus failure-handling guidance ('ask them before trying again' on done:false). It stops short of naming alternative tools by name, so it falls slightly short of a 5.

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