Delete an environment or config variable by ID to remove it from a Balena fleet, device, or service. Requires confirmation to prevent accidental removal.
Delete one environment or config variable by ID.
| Name | Required | Description | Default |
|---|---|---|---|
| kind | Yes | ||
| confirm | Yes | Must be true after reviewing the target and consequences | |
| variable_id | Yes |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the safety profile is known. The description adds the scoping detail that exactly one variable is deleted by ID, but it does not disclose whether deletion is permanent, what consequences follow, or any required permissions beyond the confirm field already present in the schema.
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 with no filler or redundant wording. Every word adds meaning: 'Delete' conveys the action, 'one' limits scope, 'environment or config variable' names the resource, and 'by ID' specifies the selector.
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 straightforward destructive operation, the description plus annotations and schema provide the essential facts: what is deleted, which parameter identifies it, the allowed kinds via enum, and the confirmation requirement. No output schema is present, so explaining return values is unnecessary; the main missing piece is usage guidance, which is already scored separately.
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?
With only 33% schema description coverage, the description partially compensates by clarifying that 'environment or config' maps to the kind enum and 'by ID' identifies the variable_id parameter. However, it does not enumerate the allowed kind values or add detail about the confirm requirement, so the parameter guidance remains incomplete.
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 states a specific verb ('Delete'), a concrete resource ('environment or config variable'), and the selection mechanism ('by ID'). This clearly distinguishes it from siblings like balena_update_variable and balena_create_variable, which perform different operations on the same resource.
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 guidance is given about when to use this tool versus alternatives, when not to use it, or how to obtain the variable_id before calling. The description only states the action, leaving the agent to infer prerequisites and alternative routing on its own.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.