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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds behavioral context the annotations cannot: the payload contents, that achievements come "newest first", and that the roster is the current one. It stops short of covering failure behavior or rate limits, which keeps it at a 4.

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 purpose, then field inventory, then the sibling routing. The field enumeration is long and partly duplicates an output schema that already exists, but it is a single dense clause rather than wasted prose, so it mostly earns its place.

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 only two params, full schema coverage, annotations, and an output schema, the description covers everything an agent needs: what it returns, how to call it, and which sibling to pick instead. Nothing material is left to inference.

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 both parameters are documented in the schema, including the game enum list and the slug example "vitality". The description only restates the same guidance ("provide slug ... optionally game to assert it"), adding no new syntax or edge-case meaning, so the baseline 3 applies.

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 a BO3.gg team profile by slug") and enumerates the payload fields, so the agent knows exactly what comes back. It also names the resource boundary against bo3_team_stats and bo3_match_history, removing ambiguity 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?

Explicit routing: "Use it to identify a team and its players; use bo3_team_stats for performance and bo3_match_history for results." That gives both when-to-use and the alternative tools with the condition that selects them, plus the calling instruction for slug and optional game.

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