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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description adds real value beyond that by noting no input is needed, that starts_at is omitted for already-live matches, and that pinned matches may omit event.name while keeping event.id. That edge-case disclosure is exactly the kind of behavior an agent cannot get from annotations, though it stops short of describing pagination or result limits.

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 purpose and scope, then the alternative routing, then the return shape and the one caveat. Dense but every sentence carries information; the field enumeration is long but reads as a single structured clause rather than padding.

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 zero-parameter read tool with annotations and an output schema, this covers purpose, alternatives, and the notable edge case. Nothing an agent needs in order to call it correctly is missing.

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?

Zero parameters, so the baseline is 4; the description correctly confirms 'no input needed', which matches the empty schema. Nothing further is required.

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 ('Get live and upcoming Counter-Strike 2 matches') and immediately scopes it against siblings by naming hltv-results for finished matches and hltv-events for calendars. An agent can distinguish this from hltv_match and hltv_results without opening any schema.

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?

Explicitly says 'Use this for the current schedule' and names the two alternatives with the condition that selects each (finished matches, tournament calendars). No inference required.

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