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

Beyond the readOnly/idempotent annotations, it discloses real behavioral facts: results derive from best 8 of 20 with caps and exceptional-score handling, at most five cards are applied in order, and missing course rating/slope/par yields a no_course_rating response. That failure mode in particular is high-value information an agent cannot get from the schema.

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 core purpose plus the illustrative example come first, followed by the data requirements and the simulation caveat. It is dense but wastes little; the trailing 'Read-only' clause largely duplicates the readOnlyHint annotation and could be dropped.

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 single-parameter tool with no output schema, the description covers what it computes, what inputs are needed, the error case, and the limit of five cards. Only the shape of the returned values (e.g. per-card projected index vs. final index) is left unstated, which is a minor gap.

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%, so the baseline is 3; the description earns above that by clarifying that cards are applied in playing order, that each card accepts gross or stableford, and that rating/slope/par are effectively mandatory even though the schema only marks scores as 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: simulate the WHS handicap index after up to five hypothetical cards, computed from the player's real federation history. The word 'hypothetical' implicitly separates it from recorded-index tools like get_handicap, but no sibling is named explicitly, so an agent must infer the boundary itself.

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 'if I shoot 80 at my club from the yellows, where do I go?' example gives a concrete when-to-use scenario, and 'A simulation, never their official index' signals it is not a substitute for the real handicap lookup. There are no explicit exclusions or named alternatives, so the routing guidance is solid but not complete.

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