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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real value beyond that: it flags that these are SteamSpy estimates rather than official Steam figures, and that access is credential-free public third-party JSON. No rate limits or freshness caveats, but the data-reliability disclosure is the important behavioral note.

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-loads the core purpose and follows with the reliability caveat, access note, parameter, and alternative. All four sentences carry weight, though the parameter restatement is redundant against the schema.

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 an output schema present, the description needn't explain return values, and it covers purpose, data-source caveats, auth profile, and routing to the alternative. Nothing an agent needs to call it correctly is missing.

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%, so the schema already documents appid. The description restates 'Numeric Steam app id,' which duplicates the schema description rather than adding format examples (e.g., where to find the id or that it maps to a store URL). Baseline 3 when the schema does the heavy lifting.

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 (returns) and a clearly enumerated set of resources (ownership, concurrent-user, playtime, and review estimates) for a Steam app from SteamSpy, a distinct data source. This distinguishes it from official Steam siblings like steam_app or steam_players without opening the 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?

Explicitly names the alternative ('Use steam_players to get the current concurrent-player count') with the condition that selects it, so the agent knows when to prefer this tool versus a sibling. Also implicitly scopes usage to SteamSpy third-party estimates.

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