mcp-electron-driver

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 effectively describes the core behavior ('REPLACING existing content') and implementation detail ('Uses Playwright's `fill`'), which gives important context about how the operation works. However, it doesn't mention error conditions, performance characteristics, or what happens with invalid selectors, leaving some behavioral aspects uncovered.

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 perfectly concise and well-structured: three sentences that each earn their place. The first states the core purpose, the second explains parameter alternatives, and the third provides crucial usage guidance. No wasted words, and the most important information (the replacement behavior) is front-loaded.

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 4-parameter mutation tool with no annotations and no output schema, the description does well but has minor gaps. It covers the core behavior, parameter relationships, and sibling differentiation effectively. However, it doesn't mention what the tool returns (success/failure indicators) or error handling, which would be helpful given the lack of output schema. The completeness is good but not perfect for this context.

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?

With 50% schema description coverage (only `ref` and `timeoutMs` have descriptions), the description adds significant value by explaining the relationship between `selector` and `ref` as alternatives ('Pass `selector` or `ref`'). This clarifies parameter semantics beyond what the schema provides. However, it doesn't explain the `text` parameter's purpose or format, which is a missed opportunity given it's the only required parameter.

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 tool's purpose with specific verbs ('Fill a text input, REPLACING existing content') and distinguishes it from sibling tools by explicitly naming an alternative ('use `keyboard_type` instead'). It identifies the exact resource (text input) and the replacement behavior, making it immediately distinguishable from similar tools like `clear_input` or `keyboard_type`.

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 provides explicit guidance on when to use this tool versus alternatives: it specifies 'For keyboard-level typing (CodeMirror, contenteditables), use `keyboard_type` instead.' This clearly defines the exclusion case and names the alternative tool, helping the agent choose correctly between sibling tools in the Playwright automation context.

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