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 clearly indicates this is a destructive operation ('Delete'), mentions security implications ('Security cleanup'), and hints at prerequisites and next steps. However, it doesn't specify authentication requirements, rate limits, or error behavior, leaving some behavioral aspects uncovered.

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?

Well-structured with clear sections (API description, Best for, Not for, Prerequisites, Next steps, Related). Every sentence earns its place by providing distinct value. The information is front-loaded with the core purpose first, followed by usage guidance.

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 destructive tool with no annotations and no output schema, the description provides good context about usage scenarios, prerequisites, and related tools. However, it doesn't describe what happens after deletion (e.g., whether changes are immediate, if confirmation is required, or what the response looks like), leaving some gaps in completeness.

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 parameters are well-documented in the schema. The description doesn't add additional parameter semantics beyond what's in the schema (e.g., it doesn't explain format of IDs or variable naming conventions). Baseline 3 is appropriate when 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 specific action ('Delete a variable'), target resource ('for a service in a specific environment'), and distinguishes from siblings like variable_set (create/update) and variable_list (read). It goes beyond just restating the name by specifying the scope of deletion.

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?

Explicitly provides 'Best for' scenarios (removing unused configuration, security cleanup, configuration management) and 'Not for' exclusions (temporary variable disabling, bulk variable removal). Also lists prerequisites (service_list) and related tools (variable_list, variable_set), giving clear guidance on 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.