env_set

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

No annotations are provided, so the description must fully disclose behavior. It states the operation ('Set') and scope, but does not mention side effects (e.g., overwriting existing variables), return value, error conditions, or whether the change affects child processes. This is insufficient for a mutating tool with no annotation support.

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, front-loaded sentence that conveys the essential purpose without any filler. Every word contributes to meaning, making it highly concise and appropriately sized for a simple tool.

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?

The tool is simple (2 parameters, no output schema), and the description combined with the schema covers the core action and scope. However, because it is a mutating operation with no annotations, missing details about return values and failure modes make it only minimally 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%, with both parameters ('variable' and 'value') described directly in the schema. The description itself does not add extra parameter semantics, so per the rubric it receives the baseline score of 3.

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 uses a specific verb ('Set') and resource ('environment variable') with scope ('for the current process'), clearly distinguishing it from sibling tools like env_get. The purpose is immediately understandable and unambiguous.

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 phrase 'for the current process' provides useful context about the scope (non-persistent, process-local), implying when this tool is appropriate. However, it does not explicitly mention alternatives (e.g., env_get) or exclusion cases, so the guidance is primarily implicit.

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