Run Playwright Test

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

Beyond the annotations, the description adds valuable behavioral context: it is a code-execution and artifact-writing boundary, requires MCP human-approval elicitation bound to the exact test digest, and may make outbound network requests. This meaningfully explains the side-effect and approval profile beyond the raw 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?

Three short sentences, front-loaded with the core action and followed by the two most important behavioral constraints. No filler or repetition; every sentence earns its place.

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 destructive, open-world code-execution tool with 8 parameters and no output schema, the description omits critical operational details: what is returned (test output, logs, screenshots?), where artifacts are written, how failures surface, and how timeout or environment parameters behave. The approval and network notes are good, but the overall definition is not complete enough for reliable invocation.

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 0% across 8 parameters, so the description must compensate, but it only vaguely maps to 'code' and 'test file'. It offers no guidance for headed, baseUrl, browser, timeoutMs, allowedEnv, or wallClockTimeoutMs, leaving an agent without enough information to configure the call correctly.

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 opens with a specific action—'Execute supplied local Playwright code or a local test file'—and clearly identifies the resource (local Playwright code/tests). This distinguishes it from siblings like generate_playwright_repro (creation), inspect_page (inspection), and scan_url (scanning), making the tool's role immediately obvious.

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 conveys clear context: this is the tool for executing local Playwright code or a test file. However, it never explicitly says when to prefer this over inspect_page, scan_url, or generate_playwright_repro, nor does it state any exclusions or prerequisites beyond 'supplied local' code.

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