List Railway Variables

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

With no annotations provided, the description carries full burden but only states it 'shows' variables, implying a read operation without details on permissions, rate limits, or output format. It doesn't disclose whether this is a safe read, if it requires authentication, or how results are structured, leaving significant behavioral gaps.

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 a single, efficient sentence that front-loads the core purpose without unnecessary words. It's appropriately sized for a listing tool, with zero wasted text, making it easy to parse quickly.

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 no annotations and no output schema, the description is incomplete for a tool with 5 parameters. It lacks details on behavioral traits, output format, or error handling, which are crucial for an agent to use it correctly. The minimal description doesn't compensate for the missing structured data.

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?

The schema has 100% description coverage, so parameters are well-documented in the schema itself. The description adds no additional parameter semantics beyond implying 'active environment' context, which aligns with the optional 'environment' parameter but doesn't provide extra meaning. Baseline 3 is appropriate as 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 action ('Show') and resource ('variables for the active environment'), making the purpose understandable. However, it doesn't explicitly differentiate from sibling tools like 'set-variables' or 'list-services', which would require mentioning it's a read-only listing operation versus mutation or other resource types.

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 minimal guidance by implying usage in the 'active environment', but lacks explicit when-to-use instructions, prerequisites, or alternatives. It doesn't clarify when to use this versus other listing tools like 'list-services' or 'list-deployments', or how it relates to 'set-variables' for mutation.

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