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

Annotations already declare readOnlyHint=true and idempotentHint=true UTF-8. The description adds a valuable behavioral detail: api_key is optional on the public endpoint but required on /mcp/mcp. This is beyond the structured data. It doesn't mention pagination or limits, but it's not essential here.

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?

Two short sentences, front-loaded with the action and scope, then a useful endpoint-specific auth caveat. No fluff or restatement of the name.

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?

Covers purpose, scope, and the only auth nuance that could trip up an agent, plus an output schema is provided. Missing deeper details about domain_id format, but the parameter is self-explanatory and required.

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 0%, so the description must add meaning. It explains the api_key auth nuance and implies domain_id selects the domain, but does not define domain_id's format or required semantics explicitly. Partial 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 clear verb ('List'), a resource ('competitions'), and the scope ('in a domain'), and explicitly includes the categories open voting and brackets. It doesn't explicitly distinguish itself from sibling list tools, but the resource is specific enough to avoid ambiguity.

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 implies usage context — listing competitions within a domain — but does not state when to choose this over sibling tools like aimrank_list_domain_entities or aimrank_get_ranking. This is adequate but not explicit guidance.

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