list_capabilities

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

With no annotations, the description carries the behavioral burden; it discloses that results depend on the current plan and that whoami is a prerequisite. It does not state that the operation is read-only or describe output shape, but the listing nature implies no destructive effect.

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?

One compact sentence with the core purpose front-loaded and the prerequisite in a dash clause. No filler or 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?

For a 0-parameter listing tool with no output schema, the description gives the essential use context and a prerequisite. It doesn't describe the return format, but the tool name and 'tools available' make the result type inferable.

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?

There are zero parameters and the schema is trivial, so the baseline is 4. The description adds no parameter-specific detail because none is needed.

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 names the resource ('tools available for your current plan') and the plan-dependent scope, clearly implying a listing action. It also points to whoami as a related tool for plan identity, helping differentiate the two. It lacks an explicit verb, but 'available' plus the tool name is sufficient.

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?

It tells the agent when to use this tool (to see plan-scoped tools) and gives a concrete prerequisite: call whoami first if the plan is unknown. It does not enumerate exclusions or alternatives beyond whoami, but for a 0-parameter list tool that is adequate.

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