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

With no annotations, the description carries the full burden and does so well: it discloses the point budget, the weekly rate limit and its error signal, the dummy-player restriction, the merge semantics for omitted traits, and that the full updated character is returned.

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 text is dense and front-loaded, with the budget rule stated before the optional goal and the return value. A few phrases are telegraphic ('next_change_at returned on too-soon'), but nothing is wasted.

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 mutation tool with no output schema, the description covers the mutation semantics, constraints, failure mode, and return value, leaving nothing an agent needs in order to call it correctly.

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 75%, and the description adds real meaning beyond it: the total-across-seven-traits budget rule, the enumeration of valid trait names, and the 'omitted traits keep their current value' semantics for both traits and goal.

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 ('Set your player's character traits') and enumerates the seven traits, so an agent can immediately distinguish this from siblings like train or register_player.

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?

It states concrete usage constraints: a 350-point budget, once-per-week frequency with next_change_at on too-soon, and that dummy players may not use the route. It does not name an alternative tool, but the constraints make the when-to-use condition clear.

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