Update environment variables

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

Annotations already include destructiveHint and idempotentHint, but the description adds critical behavioral context: anything absent from `body` is deleted, and applying changes restarts the service. This goes beyond the structured annotation information, making the side effects concrete.

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?

Each sentence earns its place: the first states the core function, the second explains the replace-all semantics and API endpoint, the third provides usage instructions, and the fourth notes the service restart side effect. The structure is logical and front-loaded with the essential purpose.

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 complex destructive update tool with no output schema, this description covers everything an agent needs: what it does, how it differs from alternatives, the full replacement behavior, and the restart consequence. It is fully self-contained and addresses potential usability pitfalls.

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%, but the description enriches the `body` parameter meaning by explaining that the entire environment variable set is replaced and anything absent is deleted. This is valuable semantic information not present in the JSON schema, clearly enhancing the agent's understanding of what `body` represents.

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 it updates and replaces all environment variables for a service via `PUT /services/{serviceId}/env-vars`. It distinguishes itself from siblings like render_update_env_var by explicitly noting it replaces the entire set, making the tool's scope 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?

Provides explicit guidance: to change one variable, use render_get_env_vars_for_service to read the current set and send it back, or use render_update_env_var for a single key. This directly tells the agent when to choose alternatives, fulfilling the dimension fully.

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