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

Annotations already declare destructiveHint/openWorldHint/readOnlyHint=false, but the description adds real context beyond them: start latency of 1-2s, a ~1 minute first-start penalty only on custom non-Ubuntu-24.04 x86_64 images because Chromium comes from the host, and the fact that get mints a fresh cdpUrl. It does not say whether stop is idempotent or what happens to an already-stopped browser.

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?

Purpose is front-loaded in the first clause and every subsequent sentence carries load-bearing detail (return values, timing, image caveat, internal address). The middle sentence is long and semicolon-chained, which slightly hurts scannability but not content quality.

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?

With no output schema, the description steps up and documents the key return (cdpUrl) for both start and get, plus the practical latency and image caveats an agent needs before calling. Only peripheral details (id meaning, stop idempotency, behavior on second start) are absent.

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 coverage is 60% (headless, width, height documented; id and action bare), and the description adds meaning: headless=false 'shows it on the sandbox's desktop with a live view', plus the semantics of each action enum value. It still never explains what the required id refers to, leaving the agent to infer it is a sandbox id.

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 resource (a Chromium browser running inside a sandbox, reachable over CDP) and its three lifecycle actions. It is clearly distinguishable from the desktop_* siblings and exec, since it names the CDP/Puppeteer/Playwright use case rather than generic desktop control.

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?

Explains what each action does in context: start returns a cdpUrl to hand to Playwright/Puppeteer/browser-use/Stagehand, get refreshes state and the cdpUrl, stop ends it, and headless=false selects the live-view desktop mode. It never names an alternative sibling or an explicit when-not condition, so it stops short of a 5.

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