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. It adds useful behavioral context: messages are stored in a session coordinator, retrievable by the recipient, and only visible to the specified recipient. However, it does not cover aspects like error handling, permissions beyond DM usage, or whether the operation is idempotent or has side effects.

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 appropriately sized with three sentences that are front-loaded (purpose first) and avoid redundancy. Each sentence adds value: the first states the purpose, the second explains storage and retrieval, and the third clarifies visibility. No wasted words, but minor room for tighter phrasing.

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 no annotations and no output schema, the description provides basic context but lacks details on return values, error cases, or system behavior. It covers storage and visibility adequately for a simple messaging tool, but does not address potential complexities like message limits or confirmation of delivery.

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 schema already documents all parameters (player_id, content, sender_id) with descriptions. The description does not add any additional meaning or syntax details beyond what the schema provides, such as format constraints or examples, meeting the baseline for high coverage.

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: 'DM can send private messages to individual players via this tool.' It specifies the verb ('send'), resource ('private messages'), and actor ('DM'), but does not explicitly differentiate it from potential sibling messaging tools (none are listed among siblings).

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 implies usage context by mentioning 'DM' and 'players,' suggesting it's for private communication in a game session. However, it lacks explicit guidance on when to use this tool versus alternatives (e.g., public messaging or other communication methods) or any prerequisites or exclusions.

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