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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds genuinely new behavior: a 5-credit cost, the latest-season default when season is omitted, that totals are summed across all stat categories, and that per-week lines are included. It stops short of noting pagination or response size, which matters given the volume implied.

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 scope qualifier and the cost statement is cleanly separated as its own sentence. The middle clause is a long enumeration, but each item is a distinct data category the caller needs, so it earns its length.

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 need not spell out return types, and it still usefully previews the payload's breadth plus cost and defaults. The one gap is that it never flags how large a full weekly-lines response will be or any pagination/truncation behavior.

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 100%, so the schema already documents player_id's GSIS format, the season default, and the REG/POST enum. The description's season-default statement merely repeats the schema text, adding no syntax or edge-case meaning beyond it; 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 and enumerates exactly what comes back: bio, draft, physicals, id crosswalk, summed season totals across stat categories, weekly lines, and games played. The 'Use for one player' opener immediately separates it from team-level siblings like get_team_stats and from the narrower get_advanced_stats.

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?

The 'Use for one player' framing implies the scope and the season default is stated, but no alternative tool is named and no when-not-to-use condition is given (e.g. use get_advanced_stats for deeper metrics, search_players for id lookup). Usage is inferable rather than explicit.

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