DM20 Protocol

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

No annotations are provided, so the description carries full burden. It states the tool lists NPCs and returns basic information, but lacks details on permissions, rate limits, pagination, or error handling. For a read operation with zero annotation coverage, this leaves significant behavioral gaps.

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 front-loaded and efficient: two sentences with zero waste. The first sentence states the action and scope, and the second clarifies the return value. Every sentence earns its place.

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 tool's simplicity (0 parameters, no output schema, no annotations), the description is adequate but minimal. It covers the basic purpose and return type, but lacks context on campaign selection, data format, or limitations, which could be helpful for an agent.

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?

The tool has 0 parameters with 100% schema description coverage (empty schema). The description doesn't need to add parameter details, so it meets the baseline. It implicitly confirms no parameters are required by not mentioning any, which 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 clearly states the tool's purpose: 'List all NPCs in the current campaign' specifies the verb ('List') and resource ('NPCs'), and 'Returns a list of all non-player characters with their basic information' elaborates on the output. However, it doesn't explicitly differentiate from sibling tools like 'get_npc' or 'create_npc', which would require a 5.

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 provides minimal guidance: it implies usage for retrieving NPCs in the current campaign but doesn't specify when to use this tool versus alternatives like 'get_npc' (for a single NPC) or 'create_npc' (for adding new NPCs). No explicit when/when-not instructions or prerequisites are mentioned.

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