Modify values for an existing ElevenLabs environment variable, or remove a non-production environment by setting its values to null.
Update Environment Variable
| Name | Required | Description | Default |
|---|---|---|---|
| values | Yes | Values to replace. Set to null to remove an environment (except 'production'). | |
| env_var_id | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false, so the safety profile is covered. The description adds no behavioral context beyond the title: no permissions, no effect on unspecified values, no reversibility, no rate-limit or auth notes.
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?
It is a single sentence, but the issue is under-specification rather than concision. Nothing is front-loaded because nothing useful is stated beyond the title.
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 a nested replacement object, no output schema, and only half of the schema parameters described, the definition omits nearly all operational context an agent would need to invoke it correctly.
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 50%: the values object has a schema description, but env_var_id has none. The description provides no parameter meaning at all, so it does not compensate for the undocumented required parameter.
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 is only 'Update Environment Variable', identical to the tool name/title. It restates rather than specifies purpose; there is no scope, no indication of what is updated, and no differentiation from siblings such as create_environment_variable or get_environment_variable.
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?
No when-to-use guidance, prerequisites, or alternatives are provided. The description does not tell the agent when to choose update_environment_variable over create_environment_variable or list_environment_variables.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.