set_env

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

Annotations provide destructiveHint=true and idempotentHint=true. The description adds auto-secret-marking behavior for keys containing specific substrings. No contradiction with annotations.

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?

Two sentences, front-loaded with purpose, then behavior. No unnecessary words.

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 simple schema and annotations, the description is sufficient. Missing details about possible side effects (overwriting existing variables) or access patterns (bulk set). Output schema is absent but not critical.

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% but parameters are simple: project_id and vars (key-value pairs). The description adds minimal additional semantics beyond the schema; it explains how vars are accessed (process.env.KEY) and secret auto-marking, but this is more behavioral than parameter-specific.

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?

Description clearly states the action ('Set environment variables for a project') and the resource ('environment variables for a project'). It distinguishes from siblings like list_env (listing) and delete_env (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?

The description explains that variables are accessible via process.env.KEY and that certain keys are auto-marked as secrets. However, it does not explicitly state when to use this vs. other tools like delete_env or set_visibility.

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