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 states the tool lists domains, implying a read-only operation, but doesn't disclose behavioral traits like whether it's paginated, rate-limited, or what format the output takes. The 'Best for' section adds some context about use cases but lacks operational details.

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 with clear sections (API tag, Best for, Prerequisites, Next steps, Related) and uses bullet points for readability. It's appropriately sized for the tool's complexity, though the 'Best for' section could be more concise. Every sentence adds value without 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 moderate complexity (3 required parameters, no output schema, no annotations), the description provides good contextual coverage with usage guidelines, prerequisites, and related tools. It lacks details on output format or behavioral constraints, but for a list operation with full schema coverage, it's reasonably complete.

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 fully documents the three required parameters (projectId, environmentId, serviceId). The description doesn't add any parameter-specific information beyond what's in the schema, such as explaining relationships between parameters or providing examples. Baseline 3 is appropriate when 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 lists domains for a service, specifying both service and custom domains. It uses the verb 'list' with the resource 'domains', making the purpose unambiguous. However, it doesn't explicitly differentiate from sibling tools like domain_check or tcp_proxy_list beyond the 'Best for' section.

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 endpoints, managing configurations, auditing), prerequisites (service_list), next steps (domain_create, domain_update), and related tools (service_info, tcp_proxy_list). This gives clear context on 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.