Railway MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively communicates this is a mutation tool ('Update'), specifies constraints (not for changing domain names or TCP proxy configuration), and mentions prerequisites. However, it doesn't address potential side effects, error conditions, or what happens to unspecified settings during updates.

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 label, best for, not for, prerequisites, next steps, related). Every sentence earns its place by providing specific 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 mutation tool with no annotations and no output schema, the description does well by specifying purpose, usage boundaries, prerequisites, and related tools. However, it lacks information about return values, error handling, or what constitutes a successful update. Given the complexity of domain configuration updates, some behavioral details are missing.

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 both parameters (id and targetPort). The description adds context about what these parameters enable ('Changing target ports', 'Updating domain settings'), but doesn't provide additional syntax, format details, or constraints beyond what the schema specifies. This meets the baseline 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 with specific verbs ('Update a domain's configuration') and distinguishes it from siblings by listing what it's best for (changing target ports, updating settings, reconfiguring endpoints). It explicitly differentiates from domain_create, domain_delete, and tcp_proxy_create 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 alternatives (delete and recreate for domain name changes). It also includes prerequisites (domain_list) and related tools (service_update), giving clear context for 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.