session

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

With no annotations provided, the description carries the full burden, and it does well by disclosing persistent state, the side effect of 'close' destroying the session, the return shape, and error format. It doesn't cover all behavioral nuances such as headless mode or page-load wait behavior, but the core operational traits are transparent.

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 efficiently structured with a purpose line, a usage-reason line, and a clean action list. Every sentence and list item earns its place, and the action enumeration is necessary because the schema provides no enum values.

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 high complexity — 10 parameters and 11 actions — the description covers nearly everything an agent needs: session semantics, action expectations, return format, and error behavior. The only notable omission is the headless parameter and more detail on waiting/timeout behavior outside the 'wait' action, but the overall picture is solid.

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; it does by documenting the session parameter and mapping each action string to its relevant arguments, including 'open (url)', 'fill (selector, text)', 'eval (js)', and 'wait (selector? / timeout_ms)'. The main gap is the headless parameter, which is never described, though its schema default partially mitigates that.

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 opens with a specific verb and resource: 'Drive a persistent browser session' with cookies and JS state kept across calls. It also distinguishes itself from one-shot scraping tools by explaining the session-memory difference, so an agent can tell it apart from the sibling scrape tools.

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?

It explicitly states when to use the tool: 'Use for login walls and multi-step flows the ladder can't handle.' It also clarifies the alternative — one-shot scrape has no session memory — and explains that each action runs against the same live page, giving clear selection guidance.

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