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 explains the tool's workflow nature, migration use cases, and constraints (not for single updates or temporary changes). However, it lacks details on permissions, rate limits, or error handling, which 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 bullet points, icons, and clear sections, making it easy to scan. Every sentence earns its place by providing distinct value (purpose, guidelines, prerequisites, alternatives, next steps), with no redundant 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?

For a mutation tool with no annotations and no output schema, the description does an excellent job covering purpose, usage context, and workflow integration. It compensates well for the lack of structured fields, though it could benefit from mentioning response format or error cases to be fully complete.

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 5 parameters thoroughly. The description adds no additional parameter semantics beyond what's in the schema (e.g., it doesn't clarify how 'serviceId' affects copying or the implications of 'overwrite'). 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 specific verbs ('copy variables') and resources ('from one environment to another'), distinguishing it from siblings like variable_set (single updates) and variable_bulk_set (bulk setting). The [WORKFLOW] tag further clarifies its scope as a multi-step operation.

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 (variable_set) and prerequisites (service_list). It also lists related tools (variable_list, service_update) and next steps (deployment_trigger, service_restart), offering 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.