Playwright MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions that the session 'record[s] Playwright actions', which implies ongoing recording, but doesn't specify what happens after starting (e.g., whether it persists across interactions, requires explicit ending, or has side effects like file creation). For a tool that initiates a stateful process, this is a significant gap in transparency.

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 a single, efficient sentence that front-loads the core purpose ('Start a new code generation session') and adds specific context ('to record Playwright actions'). There is no wasted verbiage, and every word contributes to understanding the tool's function.

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 complexity of initiating a stateful session with no annotations and no output schema, the description is incomplete. It doesn't explain what the tool returns (e.g., a session ID or confirmation), how the session integrates with other tools, or potential errors. For a tool that likely changes system state, more context is needed to guide effective use.

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 schema fully documents the 'options' parameter and its nested properties. The description adds no additional parameter semantics beyond what's in the schema, such as default behaviors or constraints. With high schema coverage, a baseline score of 3 is appropriate as the description doesn't compensate but doesn't need to.

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 clearly states the verb 'Start' and the resource 'new code generation session', with the purpose 'to record Playwright actions'. It distinguishes from siblings like 'end_codegen_session' by indicating initiation rather than termination, but doesn't explicitly contrast with 'get_codegen_session' or 'clear_codegen_session'.

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?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., whether a session must be started before using other codegen tools), nor does it explain the relationship with sibling tools like 'end_codegen_session' or 'get_codegen_session'.

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