DM20 Protocol

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It fails to describe any behavioral traits: it doesn't specify if this is a read-only or destructive operation, what happens to existing combat state, error conditions, or output format. The description is too vague to inform the agent about how the tool behaves beyond the basic action.

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?

The description is a single, concise sentence with zero wasted words. It's front-loaded with the core action ('Start a combat encounter'), making it easy to parse quickly. No unnecessary details or redundancy are present.

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?

Given the complexity of starting combat (likely involving state changes and interactions with other tools), the description is incomplete. With no annotations and no output schema, it lacks crucial details: it doesn't explain what the tool returns, error handling, or how it integrates with sibling tools like 'next_turn' or 'end_combat'. This leaves significant gaps for an agent to understand the tool's role in the broader system.

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%, with the parameter 'participants' documented as 'Combat participants with initiative order'. The description adds no additional meaning beyond this, as it doesn't elaborate on participant structure, initiative rules, or constraints. With high schema coverage, the baseline score of 3 is appropriate, as the schema handles the parameter documentation adequately.

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 'Start a combat encounter' clearly states the verb ('Start') and resource ('combat encounter'), making the purpose understandable. However, it lacks specificity about what 'starting' entails (e.g., initializing a tracker, setting initiative) and doesn't differentiate from sibling tools like 'end_combat' or 'combat_action', which are related but distinct.

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?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing participants defined), exclusions (e.g., not for ongoing combat), or related tools like 'end_combat' or 'next_turn'. The description alone offers no usage context beyond the basic action.

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