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

Annotations only declare the safety profile (readOnlyHint=false, openWorldHint=true, destructiveHint=false); the description adds genuinely non-obvious behavior beyond them — that daily mode authenticates and *resumes* the account's current UTC-day attempt rather than creating a new one. It still omits what a repeat free-mode start does and what the call returns.

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?

Two sentences, no filler, and the guest/authenticated split is front-loaded before the daily-mode constraint. Every clause carries information the agent needs.

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 should say what a successful start yields (session handle? initial game state?), and it should clarify the role of the 'name' field for guest play. It covers the auth/mode story well but leaves the invocation and return contract partially implicit.

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 carry the burden. It explains the semantics of 'mode' and 'accountToken' (required for daily), but never mentions the 'name' parameter or enumerates/describes the 'game' values, leaving half the parameters undocumented anywhere.

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 names a specific verb+resource ('Start ... play') and immediately disambiguates the two operating modes (guest free play vs. authenticated free/daily play). It clearly distinguishes itself from the read-only siblings (arcade_read_game, arcade_games) but never names a sibling explicitly to route the agent.

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 states the condition that selects daily mode ('requires an account token') and the resume behavior, which tells the agent when daily is appropriate. It stops short of naming alternatives such as arcade_create_account for obtaining the token, so the routing is clear but not exhaustive.

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