Browser MCP Server

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

With no annotations provided, the description carries full burden but offers minimal behavioral insight. It states the action but doesn't disclose what 'focus' entails (e.g., UI effects, interaction readiness, error handling), nor does it mention side effects, permissions, or performance implications. The reference to 'browser_docs' suggests missing details.

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 extremely concise with a single sentence, front-loading the core action. However, it relies on an external reference ('browser_docs'), which reduces self-sufficiency. No wasted words, but it may be overly terse for clarity.

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 no annotations, no output schema, and a vague description, this is incomplete for a tool that performs an interactive browser action. The description fails to explain what 'focus' does, its outcomes, or error conditions, leaving significant gaps for an AI agent to understand and invoke it correctly.

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%, with the 'selector' parameter fully documented in the schema. The description adds no additional meaning about the parameter beyond what the schema provides, such as selector syntax examples or constraints. Baseline 3 is appropriate since the schema does the heavy lifting.

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 states the action ('Focus an element') but is vague about what 'focus' means in this browser automation context. It references 'browser_docs' for details, which suggests the description alone is insufficient. It doesn't clearly differentiate from sibling tools like 'browser_click' or 'browser_hover' that also interact with elements.

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. The mention of 'browser_docs' implies external documentation is needed, but the description itself lacks any context about appropriate use cases, prerequisites, or comparisons to sibling tools like 'browser_hover' or 'browser_select'.

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