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

Annotations declare the mutation/safety profile, so the description's job is to add context — and it does: results land in Foundry chat, advantage and disadvantage are mutually exclusive, and the exclusivity rule requires module 8.13+. It omits whether a roll dialog or permissions are involved, keeping it short of a 5.

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?

Three tight sentences, zero filler; the core action and world scope lead, and the routing and constraint notes follow.

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 stateless roll with no output schema, the description covers where results go (Foundry chat) and the key parameter constraint. Minor omissions remain around prerequisites and the effect of advantage/disadvantage, but nothing blocking.

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 33%: actorId is documented, but advantage/disadvantage are bare booleans. The description partially compensates by stating the two are mutually exclusive, yet never explains what advantage/disadvantage mean mechanically for the roll, leaving a real gap.

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+resource ('Roll a Perception check for an actor') and immediately scopes it to D&D 5e worlds, distinguishing it from its sibling dnd5e-roll-skill by naming the equivalent invocation. An agent can select it confidently without opening the schema.

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 routes Pathfinder 2e worlds to pf2e-roll-perception, which is a real routing decision. It does not, however, clarify when to prefer this over the generalist dnd5e-roll-skill (it only says they are the same), nor when advantage/disadvantage should be requested.

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