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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so the safety profile is covered. The description adds genuinely new context: a cross-tool dependency on search_players and a 5-credit cost, which is exactly the kind of pre-call constraint annotations cannot express.

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?

Five short sentences, front-loaded with the use condition, then the two return branches, then the dependency and cost. No filler and no repetition of the title; each sentence carries distinct information.

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?

For a read-only single-entity lookup with a full output schema, 100% parameter coverage, and explicit annotations, the description is nearly complete: trigger, prerequisite, cost, and return shape are all present. The only unaddressed item is the multi-league scope supported by the league enum.

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% (2 params, one enum), so the baseline is 3. The description earns above baseline by tying player_id to its source tool ("from search_players"), giving the agent an acquisition path the schema does not state, though it says nothing about the league parameter.

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?

The description opens with a specific verb and resource ("full details for one player") and enumerates exactly what comes back for skaters vs. goalies, which is more informative than the title. It stops short of explicitly differentiating itself from close siblings like get_skater_season_stats or get_goalie_stats, so the agent must infer that this is the combined per-player view.

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?

"Use when you need full details for one player" gives a clear trigger, and "Requires player ID from search_players" states the prerequisite and the tool that supplies it. It offers no when-not guidance, e.g. when to prefer get_goalie_stats or get_player_game_log instead, so the sibling boundary is left implicit.

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