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 mentions that domain names cannot be changed (requiring delete and recreate) and excludes TCP proxy configuration, adding useful constraints. However, it lacks details on permissions, rate limits, error handling, or what 'updating domain settings' entails beyond target ports, leaving gaps 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 and front-loaded with the core purpose, followed by bullet-pointed guidelines and related steps. Every sentence earns its place, with no wasted words, making it efficient and easy to scan for key information.

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 (mutation with 2 parameters), no annotations, and no output schema, the description is mostly complete. It covers purpose, usage guidelines, and exclusions well, but lacks details on behavioral aspects like side effects or return values, which would be needed for full completeness in this context.

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) fully. The description adds no additional parameter semantics beyond what the schema provides, such as format examples or constraints. 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's purpose with a specific verb ('Update') and resource ('domain's configuration'), distinguishing it from siblings like domain_create, domain_delete, and domain_list. It explicitly mentions what can be updated (target ports, settings, endpoints), providing a focused scope.

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 (changing target ports, updating settings) and exclusions (changing domain names, TCP proxy configuration). It also lists prerequisites (domain_list) and related tools (service_update), offering clear when-to-use and when-not-to-use context.

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