Roll initiative for specific combatants. Use combat-get to find combatantIds. For rolling all at once, use combat-roll-all-initiative instead.
| Name | Required | Description | Default |
|---|---|---|---|
| formula | No | Custom formula like "1d20+5" (uses character's default if omitted) | |
| combatId | No | Combat ID (uses active combat if omitted) | |
| combatantIds | Yes | Combatant IDs to roll for (from combat-get) |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already convey that this is a non-read-only, non-idempotent operation, so the description does not need to restate the safety profile. However, it adds no behavioral context beyond the act of rolling—such as whether existing initiative values are overwritten or whether the roll affects combat state. The lack of contradiction keeps it at an adequate 3.
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?
Two purposeful sentences: the core purpose is front-loaded, the ID lookup hint is included, and the sibling alternative is stated without extra detail. No word 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?
Everything needed to select and invoke the tool correctly is present: the target combatant IDs, how to obtain them, a sibling disambiguation, and optional parameters are covered by the schema. The only minor gap is that no return/result behavior is described, but the tool is simple and the invocation path is complete.
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 schema already documents combatantIds from combat-get, optional formula syntax, and default active combat. The description's mention of combat-get adds no meaning beyond what the parameter schema already states, so baseline 3 applies.
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 states a specific verb and object—'Roll initiative for specific combatants'—and immediately distinguishes it from the sibling combat-roll-all-initiative. An agent can tell exactly what resource and scope this tool targets.
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 gives a concrete prerequisite ('Use combat-get to find combatantIds') and an explicit alternative for the when-not-to-use case ('For rolling all at once, use combat-roll-all-initiative instead'). This leaves no ambiguity about which situation selects this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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