Railway MCP Server

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

With no annotations provided, the description carries full burden. It effectively communicates this is a creation/mutation tool (implied by 'Create'), specifies use cases and exclusions, and references prerequisites and related tools. It doesn't mention permission requirements, rate limits, or error conditions, but provides substantial behavioral context for a creation tool.

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 efficiently structured with clear sections (API label, purpose, best for, not for, prerequisites, alternatives, next steps, related). Every sentence earns its place with no redundant information, and it's appropriately sized for the tool's complexity.

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 creation tool with no annotations and no output schema, the description provides excellent context about when to use it, prerequisites, alternatives, and related tools. It doesn't describe the return value or creation confirmation details, but given the comprehensive usage guidance and clear purpose, it's nearly complete for agent selection.

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 for high schema coverage.

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 as 'Create a new TCP proxy for a service' with specific verb ('Create') and resource ('TCP proxy'), distinguishing it from sibling tools like domain_create for HTTP/HTTPS endpoints. It explicitly differentiates from alternatives and related tools.

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' and 'Not for' sections, naming specific use cases (database access, external connections) and exclusions (HTTP/HTTPS endpoints, internal communication). It explicitly references prerequisites (service_list), alternatives (domain_create), and next steps (tcp_proxy_list).

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