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

Annotations only indicate create semantics (not read-only, not idempotent, not destructive), so the description carries the burden of behavioral detail. It adds valuable context: game-system-specific type validation and the fact that the system object is deep-merged over system defaults. No annotation contradiction exists.

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?

Four short sentences, each earning its place: scope, type constraints, alternative tool, and merge behavior. The purpose is front-loaded and there is no filler or restatement of schema fields.

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 5-parameter tool with a nested system object and no output schema, the description covers the required inputs, valid type values, and the main alternative path. It is slightly incomplete in that it does not mention return values or what the agent receives after creation, which would be useful when no output schema is provided.

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 adds meaning beyond the schema by listing pf2e type values that the schema's type property omits, and by clarifying how the nested system parameter behaves ('deep-merged over the system defaults').

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 ('Create a new actor') and adds the qualifier 'from scratch', which clearly differentiates it from sibling actor-create-from-compendium. Listing custom NPCs, characters, and creatures as the intended use further disambiguates the tool's scope.

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?

Explicitly directs compendium imports to actor-create-from-compendium, giving the agent a concrete decision rule. It also tells the agent that type must be valid for the world's game system and enumerates the valid values for dnd5e and pf2e, so the agent knows the constraint before invoking.

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