opendota_player_heroes

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

Annotations already indicate readOnlyHint, openWorldHint, and idempotentHint, and the description does not contradict these. It adds useful behavior context by specifying the return format, ordering by games played, and the need to join hero_id via opendota_heroes, which is beyond what annotations provide.

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?

The description is brief and well-structured, starting with a one-line purpose, followed by return format, an example, and auth note. Every sentence adds value, and the example is practical. It is front-loaded with the core purpose, making it easy for an agent to scan quickly.

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?

Despite lacking an output schema, the description provides the return fields and ordering, which is helpful. It also includes the join hint for hero_id. However, it does not explain the semantics of fields like with_games/against_games or how limit affects the aggregation, leaving some ambiguity for a complete understanding.

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?

Input schema coverage is 100%—both parameters (account_id and limit) have descriptions. The tool description does not add extra parameter meaning beyond the schema, but the schema itself is sufficient. The limit parameter's effect on the returned hero list is only partially implied ('Restrict to the most recent N matches'), and the description does not clarify this further.

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 clearly states the tool's purpose: 'Which heroes a player uses and how they perform on each.' This is specific to hero performance per player, distinguishing it from sibling tools like opendota_player_matches (individual matches) or opendota_player_winloss (overall win/loss). The example 'Hero pool' reinforces the intended use.

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 description gives clear context for when to use the tool by stating it returns hero performance data for a player and includes an example invocation. It does not explicitly exclude alternatives or mention when not to use it, but the purpose itself is sufficiently clear for most selection scenarios.

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