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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the description's job is added context — and it delivers the important consequence: snippets carry that game's publishable key inline, and 'shipping the wrong one silently pools your players into another game.' That failure mode is not derivable from annotations or schema. It does not hint at output size or token cost of a full markdown reference, which would matter for a large read.

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?

Front-loaded with the verb and return type, then the coverage list, then the usage trigger, then the parameter warning. No filler sentences, and the highest-stakes detail (wrong key pools players) is placed last for emphasis. The coverage enumeration is dense but each item maps to a distinct SDK surface an agent might need.

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 one optional parameter and no output schema, the description appropriately characterizes the return as a full markdown reference and explains every surface it covers, so an agent knows what it will get. What's missing is guidance on output volume and whether the reference is meant to be read wholesale or section-by-section.

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 100% and the schema already explains the pk_/name resolution chain, so the baseline applies. The description still adds genuine meaning by explaining the stakes of the parameter — the wrong game key silently cross-pools players — which the schema does not convey.

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 — 'Returns the full SDK reference (markdown)' — and scopes it to ONE game's key/endpoints, then enumerates the covered surfaces (rooms, identity, datastore, leaderboards, UGC, matches). It implicitly separates itself from narrow siblings, but never names get_client_snippet or get_connection_info, which an agent could easily confuse with this broader reference.

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?

Gives a clear trigger condition: 'Read this before writing client code that uses logins, saved progress, leaderboards, shared player-made content, or any game a player closes and comes back to.' It also states when to supply the optional `game` argument (multi-game studios). It stops short of exclusions — e.g., when to prefer get_client_snippet or get_connection_info instead — so half the routing decision is left implicit.

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