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

The annotations already flag destructiveHint=true and readOnlyHint=false, and the description adds valuable context beyond that: it 'Creates a session, runs the task, and auto-terminates' and warns that it 'may navigate, fill forms, and submit data on third-party websites as the task requires.' This paints a clear picture of side effects without contradicting the annotations.

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 front-loaded with the core action and environment, followed by usage guidance and an explicit sibling exclusion. Each sentence earns its place, though the embedded docs link and parenthetical are slightly extraneous. It is compact enough for an agent to parse quickly.

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?

For a tool with 15 parameters and nested objects, the description covers the essential selection criteria and behavioral expectations well. Since an output schema exists, return-value details are not required. A minor gap is that it doesn't mention the asynchronous nature (e.g., checking get_task_status or webhook notifications), but the schema and sibling tools partly compensate.

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 input schema already documents every parameter in detail. The description adds no parameter-specific semantics beyond clarifying the tool's general behavior, which is sufficient given the schema's thoroughness. Baseline 3 is appropriate.

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 states a specific verb and resource: 'Execute a browser automation task in a real Chrome browser running in a WebRun cloud environment.' It clearly distinguishes itself from trigger_workflow by framing itself as 'Best for simple one-off tasks that no saved workflow covers,' so an agent can immediately tell which tool fits.

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 gives explicit when-to-use guidance ('Best for simple one-off tasks that no saved workflow covers') and explicit when-not-to-use instructions ('Do NOT use this to run or test a saved workflow — use trigger_workflow instead'). It even maps user phrases like 'run it' and 'test it' to the correct sibling tool, leaving no ambiguity.

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