Add or update environment variable

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

The description adds the API endpoint and clarifies the env group context, but annotations already provide readOnlyHint=false, destructiveHint=false, and idempotentHint=true. No additional behavioral traits (e.g., permissions, side effects) are disclosed beyond what annotations and schema offer.

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 two concise sentences that front-load the purpose and include the specific API call. Every sentence adds value with no wasted 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?

For a mutation tool with no output schema, the description covers the action, target, and API call. The oneOf body schema is well-documented, but the description could mention response behavior or whether it replaces the variable entirely. Still, it is nearly complete given annotations.

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 coverage is 100% with descriptions for all three parameters (body, envVarKey, envGroupId). The description text does not add semantic detail beyond the schema; it merely paraphrases the variable and group context. Baseline 3 applies.

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 title and description clearly state 'Add or update environment variable' and specify that it operates on a particular environment group. The API endpoint is provided, distinguishing it from siblings like render_delete_env_group_env_var or render_retrieve_env_group_env_var.

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 states when to use this tool (add or update an env var in an env group) but does not explicitly contrast it with similar tools like render_update_env_var or render_delete_env_group_env_var. It lacks when-not or alternative guidance.

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