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 of behavioral disclosure. It effectively communicates that this is a mutation tool ('Update'), specifies prerequisites and related tools, and implies configuration changes. However, it doesn't explicitly mention potential side effects (e.g., service downtime, irreversible changes) or permission requirements, which would be helpful for a tool with 10 parameters and no output schema.

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 bullet points for best uses and exclusions, and clear sections for prerequisites, next steps, and related tools. Every sentence earns its place by adding value without redundancy, making it efficient and easy to parse.

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 (10 parameters, no output schema, no annotations), the description does a strong job by clarifying purpose, usage boundaries, prerequisites, and related tools. However, it lacks details on behavioral aspects like error handling, response format, or confirmation prompts, which would enhance completeness for a mutation tool with many optional parameters.

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%, meaning all parameters are documented in the input schema. The description doesn't add specific parameter details beyond what's in the schema, but it contextually explains that the tool updates 'service settings', 'resource limits', and 'deployment configuration', which aligns with parameters like numReplicas, buildCommand, and region. This provides high-level semantic context without redundant details.

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 with the specific verb 'Update' and resource 'service's configuration'. It distinguishes from siblings by explicitly listing what it's not for (updating environment variables, restarting services, triggering deployments), making the scope precise 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 on when to use this tool ('Best for: Changing service settings, Updating resource limits, Modifying deployment configuration') and when not to use it ('Not for: Updating environment variables, Restarting services, Triggering new deployments'), with clear alternative tools named (variable_set, service_restart, deployment_trigger). It also lists prerequisites (service_list, service_info) and next steps (deployment_trigger), offering comprehensive usage context.

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