Browser Instrumentation 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. It discloses key behavioral traits: sessions start in 'observation-only mode' (safe read state), actions require 'explicit escalation' (implying a separate permission step), and it describes the return format ('Confirmation message with session name and status'). It doesn't mention rate limits, persistence, or error conditions, but covers the essential safety and workflow context.

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 front-loaded with the core purpose, followed by well-structured sections for Args and Returns. Every sentence earns its place: the first states the action and initial mode, the second explains escalation, and the parameter/return details are necessary given the 0% schema coverage. No wasted words.

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 4 parameters with 0% schema coverage, no annotations, and an output schema (implied by 'Returns'), the description does well: it explains all parameters semantically and states the return format. However, for a tool that creates a session (a potentially stateful/mutating operation), it could mention more about error cases (e.g., duplicate names) or session lifecycle, though the output schema may cover some of this.

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%, so the description must compensate fully. It adds meaning beyond the schema by explaining each parameter: 'name' as a 'Unique name for the session' with examples, 'headless' as 'run browser without visible window', and viewport dimensions with defaults and units ('pixels'). This provides complete semantic context that the schema lacks.

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 'Create' and resource 'new browser session for observation', distinguishing it from sibling tools like browser_session_connect (connect existing), browser_session_destroy (terminate), and browser_session_list (list). It specifies the session's initial state as 'observation-only mode', which is a key differentiator from action-oriented siblings.

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 clear context: 'Sessions start in observation-only mode. Actions require explicit escalation.' This implicitly guides when to use this tool (to start a session) versus when to use escalation tools later. However, it doesn't explicitly name alternatives like browser_session_connect for reusing existing sessions or state when not to use it.

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