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 it's for GitHub-hosted projects, and mentions build processes. However, it doesn't disclose potential side effects, authentication requirements, or rate limits that would be valuable for a mutation 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 well-structured with clear sections (Best for, Not for, Prerequisites, Alternatives, Next steps, Related). Every sentence earns its place by providing actionable guidance without redundancy. The information is front-loaded with the core purpose immediately stated.

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 does an excellent job covering usage context, alternatives, and workflow integration. However, it lacks information about what the tool returns (output format) and doesn't fully address behavioral aspects like error conditions or side effects that would be important for a mutation operation.

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. The description doesn't add any parameter-specific information beyond what's in the schema. It mentions GitHub repositories generally but doesn't provide additional syntax or format details for the repo parameter.

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 creates a new service from a GitHub repository, specifying both the action (create) and resource (service from repo). It explicitly distinguishes from sibling tools like service_create_from_image and database_deploy, making the purpose specific and differentiated.

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 alternatives (service_create_from_image, database_deploy). It also lists prerequisites (project_list) and next steps (variable_set, service_update), giving comprehensive context for when to use this tool versus others.

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