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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=false, so the safety profile is covered; the description adds real value beyond that by disclosing tab behavior (reuses the site's open tab, preserves the user's own tabs) and the fact that it returns the page's visible elements and text with stable numbers. It does not say what happens if no browser session exists or how long startup takes, which are the remaining unknowns for an open-world tool.

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 core sentences are front-loaded and dense with useful facts, but the trailing enumeration of OpenTable actions ('Search restaurants with open tables, Check availability, Book a reservation...') is a catalog of sibling capabilities appended to a generic browser-open tool, and it pads the definition without helping an agent select or invoke this tool.

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 carries the return-value burden and does so ('the elements and text in view, with the same numbers'), and annotations cover the safety profile. It is nearly complete for a two-parameter session-start tool; the only omissions are failure modes (no session, unreachable URL) and how the follow-up step connects to specific sibling tools.

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%, so both params are documented, and the description does not restate them. It adds only one piece of semantics beyond the schema: that `url` targets the site's existing tab rather than always a new one. The `app` parameter — the genuinely ambiguous one — is left entirely to the schema, so the baseline of 3 is right.

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 ('Starts the user's Cloud Browser and opens `url`') with concrete scope: a real Chrome instance where the user is already signed in. It further clarifies this is the entry point ('Call it first'), so an agent can distinguish it from the many cotlet_browser_* action siblings without opening a schema.

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?

'Call it first' gives explicit ordering guidance that no other sibling tool provides, and the tab-routing rule ('site's open tab, else a new tab') tells the agent what to expect. It never names the follow-on tool (e.g. cotlet_browser_navigate or cotlet_browser_read) or states when not to use this versus them, leaving the sequencing hand-off implicit.

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