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

With no annotations supplied, the description carries the full behavior burden and does disclose meaningful traits: output includes sources, the tool abstains from eligibility judgments, and 'a rule not listed may still exist' warns about incomplete results. It does not cover behavior for an unrecognized activity name or whether the lookup is read-only against a cached vs live source, leaving some gaps.

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 tight sentences with zero filler; the capability comes first and the two limitations follow immediately. Every clause earns its place.

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 one-parameter read tool with no annotations and no output schema, the description covers the core capability, the evidentiary nature of results ('with sources'), and the key caveats. It stops short of describing the return structure in any detail or what happens on an unknown activity, which would matter without an output schema.

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% and the single 'activity' parameter already ships examples, so the schema does the heavy lifting. The phrase 'one activity or track' adds a mild clarification that trail/track names are valid inputs, but nothing about format, aliases, or ambiguity handling.

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 opens with a specific verb and resource: 'List the published age, height, weight, health and safety rules' for 'one activity or track.' It also carves out a scope boundary ('never decides whether a person can take part') that separates it from advisory siblings like get_answer or travel_faq.

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 scope exclusion ('Lists rules only: it never decides whether a person can take part') tells the agent when this tool is the wrong choice, which is useful negative guidance. However, it never names the alternative tool to use for an eligibility decision, so the routing is implied rather than explicit.

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