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

Adds useful side-effect context ('Results appear in Foundry chat') and a constraint ('Never both advantage and disadvantage'), which goes beyond the annotations. Annotations already declare non-read-only, non-idempotent behavior; the description does not explain output format or failure modes.

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, front-loaded with the action and ending with a hard constraint. Every sentence carries operational information.

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?

Covers actorId sourcing, skill-code usage, output destination, and the advantage/disadvantage rule. No output schema exists, and return-value detail is not described, but the chat-result note largely covers it.

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 50%, so the description helps: it clarifies that skill codes (not names) are used via examples, and it states the advantage/disadvantage mutual exclusion, which the schema does not enforce. actorId points back to actor-list. Some fields like advantage semantics remain undocumented.

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 ('Roll D&D 5e skill check') and gives examples (Stealth, Perception). Not fully distinguished from dnd5e-roll-ability or roll-dice siblings, but the skill-check framing is clear.

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 says 'Use for ability checks with proficiency' and directs the agent to actor-list first to get actorId. Does not compare against dnd5e-roll-ability or roll-dice, so the sibling routing is incomplete.

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