Railway 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. It describes the tool's purpose and context but lacks details on behavioral traits like pagination, rate limits, authentication requirements, or error handling. The description doesn't contradict any annotations (since none exist), but it doesn't fully compensate for the missing annotation coverage.

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 well-structured and front-loaded with the core purpose, followed by organized sections (Best for, Prerequisites, Next steps, Related). Every sentence earns its place by providing actionable information without redundancy or fluff.

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 lack of annotations and output schema, the description does a good job covering usage context, prerequisites, and related tools. However, it doesn't describe the return format or behavioral aspects like pagination, which would be helpful for a list operation. The completeness is strong but not perfect for a tool with no structured output documentation.

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 three parameters thoroughly. The description doesn't add any parameter-specific information beyond what's in the schema, maintaining the baseline score of 3. It doesn't explain parameter interactions or provide additional context about the parameters.

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 specific action ('List all environment variables for a service') with the resource ('service'), distinguishing it from sibling tools like variable_bulk_set or variable_delete. It explicitly mentions the scope ('for a service') and provides a clear verb+resource combination.

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 guidance with 'Best for' use cases (viewing configuration, auditing, checking connection strings), prerequisites ('service_list'), next steps ('variable_set, variable_delete'), and related tools ('service_info, variable_bulk_set'). This clearly indicates when to use this tool versus alternatives.

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