list_variables

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

Annotations already declare readOnlyHint=true. The description adds value by disclosing that secret variable values are returned as null, which is a critical behavioral trait not captured by annotations. This goes beyond mere read-only safety.

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 concise: three sentences, front-loaded with the core purpose, followed by output details and usage guidance. No superfluous information.

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 simple list tool with one parameter and no output schema, the description covers all necessary aspects: what it lists, the masking of secrets, and how to use the results. It is fully complete.

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 a clear description for group_id. The tool description does not add additional meaning beyond what the schema provides for parameters, so it meets the baseline for high coverage.

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 the tool lists variables in a Codemagic variable group and specifies the output (IDs, names, values, with secrets as null). It distinguishes itself from sibling tools like add_variable, delete_variable, and update_variable by mentioning usage of variable IDs with them.

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 provides clear context: it indicates where the group_id comes from (list_variable_groups) and suggests that the output IDs are used with update_variable and delete_variable. While it doesn't explicitly state when not to use it, the guidance is sufficient.

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