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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds genuinely useful behavioral context: a criterion is mandatory and an empty call is a misuse pattern. It stops short of describing result shape, but an output schema exists so that is acceptable.

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 tight sentences: purpose and criteria first, the mandatory-criterion constraint second, and the routing preference third. No filler and the most decision-relevant information is front-loaded.

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 full schema coverage, rich annotations, and an output schema that carries return values, the description covers everything an agent needs to select and invoke this tool correctly. The key pitfalls (empty call, guessing selectors) are called out.

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 all 10 parameters. The description only echoes the criterion parameters (selector/text/role) without adding format or usage detail beyond what the schema states, which is the baseline 3 case.

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 (locate) plus resource (visible web elements) and the three criteria it accepts (CSS selector, text, ARIA role), and notes the output value (reusable selectors/bounds). It also distinguishes itself from siblings by naming browser_snapshot for enumeration and browser_action for subsequent actions.

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?

Explicit when-to-use ('when the user needs to locate visible web elements') plus a when-not ('use browser_snapshot, not an empty browser_find, to enumerate page structure') and an ordering preference ('Prefer this before browser_action rather than guessing selectors or coordinates'). Alternatives and the selecting condition are both spelled out.

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