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

Annotations already declare readOnlyHint/openWorldHint, so the safety profile is covered. The description adds genuinely non-schema context: the `available` flag semantics, i.e. it is false until VLR publishes the tab for a fresh match — a real behavioral caveat an agent would otherwise misread as an error. No coverage of rate limits or failure modes beyond that.

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?

Purpose and payload lead, then the availability caveat, then id sourcing — a sensible priority order. The payload enumeration is dense but every item earns its place by telling the agent what data it will get that the scoreboard tool does not provide.

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?

With an output schema present, return-value shape need not be explained, and the description covers purpose, id provenance, and the availability edge case. The only residual gap is that per-map versus whole-match grouping is asserted but not qualified (e.g. how maps are keyed), which the output schema presumably handles.

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 coverage is 100%, and the schema description already says the id is a required numeric VLR match id from vlr_matches/vlr_results or an event page. The description's final sentence largely restates that, adding only the vlr_event_matches source name, so it does not meaningfully enrich parameter semantics beyond the schema. Baseline 3 applies.

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 ("Returns the Performance tab of one VLR.gg Valorant match") and then enumerates the exact payload: kill matrices, multi-kills, clutches, econ rating, plants/defuses. It explicitly separates itself from vlr_match ("use vlr_match for the scoreboard"), so an agent can distinguish it from the many sibling VLR tab tools without opening schemas.

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?

Gives an explicit alternative with a selection rule (vlr_match for the scoreboard) and tells the agent exactly where the required id comes from (vlr_matches, vlr_results, vlr_event_matches). It does not address the other tab siblings (vlr_match_economy, vlr_match_rounds), so the exclusion set is incomplete, but the core routing is clear.

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