Hover

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

Annotations already declare readOnlyHint=false and openWorldHint=true, so the agent knows this interaction can have side effects. The description adds that hovering can reveal UI elements, which is useful behavioral context. However, it doesn't disclose potential failure modes (e.g., element must be visible) or that it may trigger events like mouseover handlers. Given annotations cover the general behavior, this is adequate but not rich.

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 two sentences: the first states the action and a motivating example, the second explains how to address the element. It's front-loaded with the core purpose, no redundant wording, and every sentence earns its place. Excellent conciseness.

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?

The description covers the essential 'what' and 'how to address' for a hover tool. It mentions the snapshot context for refs, which is important. It doesn't explain return values (no output schema exists) or discuss error handling, but those are not typically required. For a tool with six parameters and one required, this is reasonably complete for successful 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 coverage is 100%, so all parameters are documented individually. The description adds integrative value by summarizing the alternative targeting methods (ref, css, role+name) and noting that refs come from the latest snapshot. This helps the agent understand the relationships between parameters and their precedence, which goes beyond the schema's per-parameter descriptions.

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 performs a hover action on an element, with a concrete example use case (revealing a menu or tooltip). It specifies the resource (element) and the action (hover), which distinguishes it from sibling tools like browser_click or browser_type. However, it doesn't explicitly contrast with those siblings, so it's slightly above average but not perfect.

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 provides a clear context for when to use the tool ('e.g. to reveal a menu or tooltip') and explains the different addressing methods (ref, css, role+name). This gives an agent enough context to decide when hover is appropriate, though it doesn't explicitly state exclusions or alternatives. The mention of 'from the latest browser_snapshot' for refs adds valuable usage guidance.

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