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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and non-open-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: a hard cap of 10 results per call and the fact that each result carries a registration link plus a fallback calendar URL for the complete list.

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 sentences, zero filler. The scoping axes (sources, country, date range) come first and the return behavior second, which is a sensible front-loaded structure.

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 no output schema, the description carries the burden of describing returns and does so: result cap, per-result registration link, and a full-list fallback URL. Combined with annotations covering safety and the 100%-covered schema, an agent has everything needed to call and interpret this tool.

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 100%, so all five parameters (including defaults, patterns, enum for lang, and the max-10 limit) are already documented. The description only reinforces the country/date-range and result-cap semantics rather than adding syntax or format detail, so 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 ('Upcoming BJJ and grappling competitions'), names the data sources (IBJJF, AJP, Smoothcomp), and scopes it by country and date range. This clearly distinguishes it from siblings like find_gyms and list_places without needing to open 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?

Gives clear context on what it returns and the key selection axes (country, date range, federations), plus a note to use the BJJ Square calendar page for the full list. It stops short of explicit when-to-use/when-not guidance or naming a sibling alternative, so it is clear but not fully directive.

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