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

The annotations are all false/neutral, so they do not disclose much about side effects. The description adds useful behavioral context by stating that results appear in Foundry chat, which tells the agent the tool produces visible game-state output rather than just returning a value. This is meaningful context beyond the annotations.

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 short sentences, each earning its place: the first states the core action, the second gives the triggering use case, and the third gives a necessary prerequisite. No filler or redundant repetition of schema details.

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 simple two-parameter roll tool with no output schema, the description covers the action, when to use it, a key prerequisite, and where results go. It is sufficiently complete for an agent to invoke it correctly; a minor gap is that it does not describe what happens on invalid actor IDs or whether the save is automated against a DC, but that is not essential for selection and invocation.

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%, and the ability parameter already includes a full enum with expanded descriptions. The description adds workflow guidance ('Use actor-list first to find actorId') but does not enrich parameter semantics beyond what the schema already provides, so the baseline of 3 is appropriate.

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-resource pair, 'Roll D&D 5e saving throw,' and clarifies the domain enough to distinguish it from siblings like pf2e-roll-save, dnd5e-roll-ability, and dnd5e-roll-skill. The phrase 'resisting spells, traps, or effects' also helps identify saving throws versus ability checks or attacks.

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 description explicitly states when to use the tool: 'Use when resisting spells, traps, or effects.' It also gives a practical prerequisite, 'Use actor-list first to find actorId.' However, it does not explicitly say when not to use it or name an alternative roll tool, so it stops just short of a 5.

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