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

Goes well beyond the annotations: discloses that a live user-visible session is created, that it is authenticated as the user, that every started minute costs credits, and that the session ends on close or 3 minutes after the last call. This billing and lifecycle context is exactly the kind of behavior an agent cannot infer from readOnlyHint/openWorldHint, and nothing contradicts those hints.

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?

Identity is front-loaded in the first sentence, followed by routing, return value, and cost terms in four dense sentences with no filler. Each sentence carries information an agent needs before calling.

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?

Covers auth context, return value, session lifetime, and billing despite having no output schema, so an agent can call it correctly. The one substantive hole is the open-vs-navigate boundary with cotlet_browser_navigate, which the description never resolves.

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 one parameter at 100% schema coverage, the schema already defines `url` fully including the app-browser nuance. The description's 'Opens `url` when given' only hints that the parameter is optional (required: 0), adding little beyond the structured data.

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?

States a specific verb and resource — wakes a real Partiful Cloud Browser signed in as the user — and says it opens `url` and returns the page URL and title. It distinguishes itself from the Partiful domain tools, but never contrasts with its closest sibling, cotlet_browser_navigate, which also goes to a URL.

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?

'Use it for what the Partiful tools do not cover' gives a clear routing rule against the non-browser siblings, and the cost/auto-close note implies when to be economical. It offers no explicit when-not or alternative among the browser siblings (navigate, click, read), leaving that choice to inference.

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