EVE Online Companion MCP Server

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 mentions that the tool sets an active character for use by other tools, which implies a state change, but it doesn't cover critical aspects like whether this requires authentication, if it's reversible, potential side effects, or error conditions. For a tool that likely involves authentication or session management, this is a significant gap.

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 extremely concise and front-loaded: it states the core purpose in the first sentence and adds crucial context in the second. Every sentence earns its place by providing essential information without any waste or redundancy.

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 complexity (state management for authentication), lack of annotations, and no output schema, the description is minimally adequate. It explains the purpose and usage but misses behavioral details like authentication requirements or error handling. The context signals show a simple parameter structure, which the description aligns with, but it doesn't fully compensate for the lack of annotations.

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 input schema has 100% description coverage, with the parameter 'character' documented as 'Character name or character ID to make active.' The description adds no additional parameter semantics beyond what the schema provides, such as format examples or constraints. With high schema coverage, the baseline score of 3 is appropriate, as the schema does the heavy lifting.

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: 'Set the active character.' It specifies the verb ('Set') and resource ('active character'), making it easy to understand what the tool does. However, it doesn't explicitly differentiate from sibling tools like 'eve_auth_list_characters' or 'eve_auth_remove_character' beyond the implied context of switching versus listing or removing.

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 explicit usage guidance: 'Tools without an explicit character_name parameter will use this one.' This clearly indicates when to use this tool (to set a default character for other tools) and implies when not to use it (if a tool already has a character_name parameter). It effectively distinguishes its role in the workflow without naming alternatives.

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