browser_run_code_unsafe

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

The description explicitly discloses the critical behavioral trait of executing arbitrary JavaScript in the server process, adding the 'RCE-equivalent' warning beyond the annotations' destructiveHint. This provides meaningful context about the tool's power and risk, going beyond the structured annotation flags.

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, front-loaded with the primary purpose and followed immediately by a crucial safety warning. Every word earns its place, with no redundancy or 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?

Given the simple structure (2 params, no output schema) and the presence of annotations and detailed schema, the description provides sufficient context for a risky tool. It covers purpose and danger, though it does not elaborate on return values or side effects, which are not critical given the schema's code example returns a value and the tool's open-ended nature.

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 for parameters is 100%, with thorough descriptions in the schema itself (including a code example and semantics for filename precedence). The tool description adds no additional parameter-level meaning, so it sticks to the baseline of 3 for high 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?

The description uses a specific verb ('run') and resource ('Playwright code snippet'), and clearly distinguishes the tool from siblings by stating it executes arbitrary JavaScript in the Playwright server process, making it RCE-equivalent. This differentiates it from browser_evaluate or other browser-interaction tools.

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 explicitly state when to use this tool versus alternatives like browser_evaluate, but the 'unsafe' and 'RCE-equivalent' warning implies it is intended for advanced or unrestricted scenarios. Usage guidance is implied rather than explicit, so it falls short of providing clear when/when-not direction.

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