sessions

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

No annotations are provided, so the description carries the full burden. 'List' clearly signals a read-only operation, and the scope is explicitly defined. However, it does not disclose potential limitations such as filtering scope, real-time freshness, or behavior when no sessions are active.

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?

A single sentence with no filler. The verb is front-loaded, and the descriptive qualifiers add meaning without bloat.

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?

This is a simple parameterless listing tool with an output schema available, so the description does not need to document return values. It provides enough context to invoke the tool, though slightly more usage context would improve 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 has zero parameters and schema coverage is 100%, so there is nothing for the description to explain. The baseline of 4 applies because parameter semantics are irrelevant here.

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 a specific resource ('active playback sessions'), then adds useful detail about what is included: who is watching, what they are watching, and on which device. This clearly distinguishes it from sibling tools like search or info.

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 wording implies use when an agent needs current playback session information, but it does not explicitly say when to prefer this over sibling tools or when not to use it. No alternatives or exclusions are mentioned, leaving some selection to inference.

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