Add combatants

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

Annotations already indicate idempotentHint=true, but the description adds concrete behavioral details: an unknown id stops the entire operation and tokens already in the encounter are not added twice. This goes beyond the structured annotations and helps an agent predict failure and duplicate handling.

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 dense sentences deliver the core action, token source, failure behavior, and duplicate prevention without wasted words. The most important information is front-loaded in the first sentence.

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?

The description covers the key operational constraints: token source, unknown-id atomicity, and duplicate handling. With a 100%-covered schema and idempotentHint annotation, the remaining details are adequately supported, though it stops short of describing the exact success output or post-add state.

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 description coverage is 100%, so the parameters are already well documented. The description reinforces the role of sceneIdentifier and the source of tokens, but it does not add meaning beyond what the schema provides. Baseline 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 uses a specific verb ('Add') and resource ('tokens to a combat encounter as combatants'), making the tool's function immediately clear. It also implicitly differentiates from siblings like remove-combatants and update-combatant by focusing exclusively on addition.

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 explains the token source (encounter scene, sceneIdentifier, or active scene), which provides useful context for when the tool can be used. However, it does not explicitly state when to prefer this tool over alternatives or mention exclusions, so usage guidance is implied rather than direct.

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