mcp-electron-driver

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the tool returns a bounding box 'of the first matching element,' which implies it selects only one element and may ignore others. However, it doesn't disclose error handling (e.g., what happens if no element matches), performance characteristics, or side effects. The description adds some context but leaves significant gaps for a tool with no annotation coverage.

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 highly concise and front-loaded: the first sentence states the core purpose, the second explains parameters, and the third provides usage context. Every sentence earns its place with no redundant information, making it efficient and easy to parse.

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 tool's moderate complexity (2 parameters, no output schema, no annotations), the description is minimally adequate. It covers the purpose and parameters but lacks details on return values (e.g., bounding box format), error cases, or integration with sibling tools beyond a vague reference to 'snapshot.' For a tool with no output schema, more information on the return type would be beneficial.

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 50% (only 'ref' has a description). The description compensates by explaining the parameter semantics: 'Pass `selector` or `ref`' clarifies that these are alternative inputs, and it adds context that 'ref' is 'from snapshot,' linking to a sibling tool. This provides meaningful guidance beyond the schema, though it doesn't detail the format or constraints of 'selector'.

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: 'Get the bounding box of the first matching element in CSS pixels.' It specifies the verb ('Get'), resource ('bounding box'), and scope ('first matching element'), though it doesn't explicitly differentiate from siblings like 'elements_list' or 'snapshot' which might also retrieve element information. The mention of 'CSS pixels' adds useful specificity.

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 some usage context: 'Useful before drag operations' implies a specific scenario, and it mentions passing 'selector' or 'ref' as parameters. However, it doesn't explicitly state when to use this tool versus alternatives like 'elements_list' (which might list multiple elements) or 'snapshot' (which might capture broader state), nor does it provide exclusions or prerequisites.

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