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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantial behavior beyond them: owned games are omitted, only public profiles imho.run already has will work, failure returns a single 'unavailable' error with an actionable link, and adult-content filtering is best-effort. These are exactly the operational traits an agent needs.

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?

Three dense sentences, front-loaded with the core purpose before routing and constraints. Every clause carries operational information, though the middle sentence packs profile format, availability, and error behavior tightly enough to be slightly heavy.

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?

An output schema exists, so return values need not be described, and the description covers the key limits and failure mode. Minor gaps remain: the 'why' lines referenced indirectly by lang are never explained here, and filter semantics are delegated to recommend.

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 75% schema coverage the schema carries most of the load, but the description adds real meaning: profile must be a SteamID64 or /profiles/<SteamID64> link, not a custom /id/ name. The filters object is handled by cross-reference ('same meaning as in recommend') rather than restated, which is efficient but leaves lang and n purely to the schema.

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+resource: Steam game recommendations ranked against the player's own public library, with owned games excluded. It explicitly contrasts itself with games_like and recommend, so an agent can distinguish it from 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?

Gives an explicit trigger (user supplies a Steam profile and wants general picks for their taste) and an explicit exclusion that routes to alternatives ('for games like X' use games_like or recommend). It also states the profile-availability precondition and what happens when it is unmet.

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