list_variables

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

Annotations only declare readOnlyHint=true; the description adds genuinely useful behavior beyond that: secret variables are returned by name only and their values are never exposed. It does not describe permissions/auth needs or the return shape, but the key security caveat an agent needs is present.

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?

Two sentences, front-loaded with the core action, followed immediately by the one caveat that matters (secret values hidden). Every clause earns its place with no redundancy.

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 an output schema present, return values need not be explained, and a zero-parameter read-only listing tool needs little else. The description covers the non-obvious secret-handling behavior, leaving nothing an agent must know before calling it.

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?

The tool takes zero parameters, so the baseline is 4. The description adds the {{name}} interpolation convention, which is context rather than parameter documentation, and nothing is missing because there are no inputs to document.

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?

States a specific verb ('List') and resource ('{{variables}} defined in Plunger'), and the note about secret variables sharpens the scope. No sibling tool (list_saved_requests, list_workflows, get_history) operates on variables, so the resource alone disambiguates it.

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 explains how variables are consumed in requests ('use them in a request as {{name}}'), but that is about the variables, not about when to invoke this tool. There is no guidance on when to list vs. set_variable/delete_variable, and no prerequisites or exclusions.

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