browser_evaluate

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the page context and the JSON-serializable result, but it does not warn that arbitrary JS may mutate page state, trigger navigation or network requests, or fail on non-serializable values.

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?

A single front-loaded sentence with zero filler: it states the action, the target context, and the return behavior. Every word contributes.

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 annotations and no output schema, the description should explain side effects, error behavior, and return-value limitations. It only covers the happy path, leaving an agent without enough information to use the tool safely and correctly.

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?

The schema only defines 'expression' as a string, so the description adds meaning by identifying it as a JS expression. However, it does not clarify expected syntax, async handling, or how return values are serialized, so it only partially compensates for the 0% schema coverage.

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, 'Run', and a specific resource, 'a JS expression in the page context', while also describing the return behavior. This clearly distinguishes it from sibling tools like browser_click and browser_snapshot.

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 does not say when to prefer this over browser_console, browser_snapshot, or other siblings, and it gives no exclusions. The intended use is only implied by the phrase 'JS expression', not stated.

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