rpg-mcp

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this is a list operation with optional filtering, but doesn't mention whether this returns all characters in the system or is limited by permissions, whether results are paginated, what format the output takes, or any rate limits. For a list tool with zero annotation coverage, this is inadequate.

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, efficient sentence that states the core functionality upfront. There's no wasted language or unnecessary elaboration - every word contributes directly to understanding the tool's purpose.

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?

For a list tool with 2 parameters (one undocumented), no annotations, and no output schema, the description is insufficient. It doesn't explain what the output looks like, whether there are limitations on what's returned, or how the 'sessionId' parameter affects results. The description provides basic functionality but lacks necessary context for effective use.

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 description mentions optional filtering by type, which corresponds to the 'characterType' parameter with its enum values. However, it doesn't mention the 'sessionId' parameter at all. With 0% schema description coverage (neither parameter has descriptions in the schema), the description adds some value but doesn't fully compensate for the undocumented 'sessionId' parameter.

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 verb ('List') and resource ('characters'), making the purpose immediately understandable. However, it doesn't differentiate this from similar sibling tools like 'get_character' (singular retrieval) or 'get_unassigned_characters' (filtered by assignment status), so it doesn't reach the highest score.

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 no guidance on when to use this tool versus alternatives. It mentions optional filtering by type, but doesn't explain when filtering is appropriate or how this tool compares to other list/retrieval tools in the sibling set (e.g., 'list_corpses_in_encounter', 'list_parties').

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