verify_locators

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

Annotations already declare this is a safe, read-only, idempotent, non-open-world operation, so the bar is lower. The description adds real value beyond them by disclosing the return shape (matches, uniqueness, first matched element per expression, plus a summary) and the CI drift-check scenario.

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 sentences, front-loaded with the core action, then usage and a secondary CI scenario. Dense but every clause carries information; no filler.

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 compensates by describing what the tool returns. Combined with fully documented parameters and safety annotations, an agent has enough to call it correctly, though the relationship to session_verify_locators remains unspecified.

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 all five parameters including url, locators, viewport, wait_for, and wait_selector are already documented with defaults, enums, and constraints. The description adds no parameter-level detail beyond what the schema provides, so the 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?

States a specific verb and resource: counting Playwright expressions against a live page, and notes it uses the same engine that verified the extraction. The purpose is unambiguous, but it does not explicitly distinguish itself from the sibling session_verify_locators, leaving the agent to infer the difference.

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 when-to-use context: 'Use after writing a test' with instructions to paste the spec's getBy*/locator expressions, and a second use case as a CI drift check. No exclusions or explicit sibling comparison are provided, but the triggering conditions are concrete.

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