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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral fact — the tool depends on an external third-party service ('via STRATZ') and, per the schema's _apiKey description, a user-supplied BYO token. However, no failure modes, rate limits, or data-freshness behavior are disclosed.

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?

A single front-loaded sentence in which every clause earns its place: action, resource, key parameter, decision-relevant return fields, and data source. There is zero filler, and the most important scoping information appears first.

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 simple 2-parameter read-only fetch with rich annotations, the description covers the essentials: purpose, lookup key, return data fields, and external dependency. With no output schema, the field list effectively serves as the return contract. Minor gaps remain around response shape and failure behavior for an invalid token or unknown player.

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 50%: _apiKey is fully documented in the schema (BYO token, free at stratz.com), but steam_account_id has only a type and no description. The tool description's 'by Steam account id' partially compensates by identifying it as the lookup key, and the schema example shows a concrete value, but this is modest added meaning rather than full compensation.

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 states a specific verb ('Fetch'), a specific resource ('a Dota 2 player's profile'), the lookup key ('by Steam account id'), and the exact data returned (Steam name, profile URL, avatar, total match count, win count) via a named source ('via STRATZ'). The listed return fields clearly distinguish this from sibling tools like player_matches and player_heroes, which cover different data scopes.

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 return-field list implies this is the tool for profile-level overview data (identity plus aggregate counts), so an agent can infer when to use it. However, the description never explicitly names alternatives or states when-not-to-use it, leaving the differentiation from closely related siblings (player_matches, player_heroes) implicit.

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