Set Railway Variables

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 states the tool sets environment variables, implying a write/mutation operation, but doesn't mention critical behaviors like whether this requires specific permissions, if changes are reversible, potential side effects (e.g., triggering deploys), or rate limits. This is inadequate for a mutation tool with zero annotation coverage.

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 directly states the tool's purpose without unnecessary words. It's appropriately sized and front-loaded, making it easy to parse quickly while conveying the essential action and target.

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 operation with 5 parameters) and lack of both annotations and output schema, the description is insufficient. It doesn't explain what happens after setting variables (e.g., success/failure responses, whether deploys are triggered by default), leaving significant gaps for an AI agent to understand the tool's full behavior and outcomes.

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 doesn't add any parameter-specific information beyond what's in the schema, such as examples or constraints not captured in structured fields. This meets the baseline for high schema coverage but doesn't provide extra value.

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 ('Set') and resource ('environment variables for the active environment'), making the purpose immediately understandable. However, it doesn't explicitly distinguish this tool from sibling tools like 'list-variables' or 'create-environment', which could help with similar operations in the Railway context.

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 no guidance on when to use this tool versus alternatives like 'list-variables' for checking existing variables or 'create-environment' for environment setup. It mentions 'active environment' but doesn't clarify prerequisites or contextual constraints, leaving usage scenarios ambiguous.

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