balena_list_variables

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

Annotations already indicate readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safe read behavior is covered. The description adds a little context by naming the resource scopes (fleet, device, service, service installation), but discloses no additional behavioral traits beyond that. 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?

The description is a single sentence with no filler and is front-loaded with the action and resource. However, it is slightly too sparse to serve as the sole source of guidance, so it does not earn a 5. It is still appropriately brief for a simple list operation.

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?

With no output schema and 0% schema description coverage, the description is incomplete for an agent to call the tool correctly. It does not explain how kind and owner_id interrelate, what the response contains, or what the allowed enum values mean concretely. Given the tool's complexity and lack of other documentation, more context is needed.

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 0%, so the description must compensate for parameter meanings, but it does not explain owner_id, top, or skip. The phrase 'environment or config variables for a fleet, device, service, or service installation' loosely maps to the kind enum, but the description does not clarify how owner_id relates to each kind or how pagination works. This is insufficient for a tool with four parameters.

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 a read operation: 'List environment or config variables' for four scopes. It distinguishes this from variable mutation siblings like balena_create_variable, balena_update_variable, and balena_delete_variable. It does not explicitly contrast with other list tools, but the resource focus is specific enough.

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 on when to use this tool versus alternatives such as balena_get_fleet or balena_list_tags. There is no mention of prerequisites, selection criteria, or exclusions. The verb 'List' implies a read operation, but no explicit when/not guidance is provided.

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