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 the tool 'returns DC and whether a check is required', which describes output behavior. However, it doesn't disclose important behavioral aspects like whether this is a read-only calculation (likely, but not stated), what happens with invalid inputs, whether it has side effects, or any performance considerations. For a calculation tool with zero annotation coverage, this leaves significant 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 perfectly concise at two sentences that each earn their place. The first sentence states the core purpose, and the second sentence explains the return values. There's zero wasted language, and the information is front-loaded with the primary function stated immediately.

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 calculation tool with 3 parameters, no annotations, and no output schema, the description provides basic but incomplete context. It explains what the tool calculates and what it returns, but doesn't cover error conditions, side effects, or detailed behavioral expectations. The absence of output schema means the description should ideally explain return format more thoroughly, which it only does at a high level.

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 67% (2 of 3 parameters have descriptions). The description doesn't add any parameter-specific information beyond what the schema provides. It mentions 'character class/level' which relates to characterId, but doesn't explain parameter relationships or provide additional context. With moderate schema coverage, the baseline 3 is appropriate as the description neither compensates for gaps nor adds value beyond the schema.

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: 'Calculate the DC required to use a spell scroll' with the specific verb 'calculate' and resource 'DC'. It distinguishes from sibling tools like 'check_scroll_usability' or 'use_spell_scroll' by focusing on calculation rather than verification or activation. However, it doesn't explicitly contrast with these siblings in the description text.

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 'based on character class/level', suggesting it's for determining scroll usability requirements. However, it doesn't explicitly state when to use this tool versus alternatives like 'check_scroll_usability' (which might verify usability) or 'use_spell_scroll' (which might actually use the scroll). No explicit when-not-to-use guidance or prerequisite information is provided.

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