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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description is not responsible for safety disclosure. It adds meaningful behavioral context by enumerating the six comparison dimensions (body part measured, freeze frame, position alone as offence, level situations, resets, exempt restarts) and clarifying 2021 hockey offside nuances. It does not describe output format, but the comparison content is well specified.

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?

The description is front-loaded and structured with headings, but it is longer than needed for a no-argument tool. Points such as 'commonest way to get either wrong', 'routinely conflated', and 'borrowing the answer from the wrong sport is wrong on most of them' repeat similar ideas. The ownership URL and detailed delegate rationale add context but could be trimmed.

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 tool with no parameters, read-only annotations, and no output schema, the description covers purpose, usage, dimensions, and argument expectations. The only notable omission is the exact output format, but 'Returns the comparison' plus the listed dimensions is likely sufficient for an agent to invoke and interpret the result.

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?

The tool takes zero parameters, and the description explicitly states 'Takes no arguments.' This removes any risk of an agent inventing inputs. With no parameters to document, the description fully covers the parameter surface beyond the empty schema.

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 action and resource: 'Returns the structural differences between soccer offside and hockey offside, one dimension at a time.' It also states when to use it, asking 'how the two compare', which clearly distinguishes it from the sibling tool 'offside' that likely handles a single sport. No ambiguity about what the tool does.

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 gives explicit use cases: use it when someone asks how the two sports compare, and before reasoning about one sport using intuition from the other. It does not explicitly name alternatives or say when not to use it, but the context is clear enough for an agent to route correctly.

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