list_sessions

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

With no annotations provided, the description carries the burden of explaining behavior. It does disclose that the tool returns session spend totals and liveness status, which implies a read-only listing. However, it does not explicitly state that there are no side effects, nor does it mention authentication, ordering, pagination, or session scope.

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, compact sentence that front-loads the core output and key attributes. Every word earns its place and there is no redundant or unclear filler. It is an excellent model of conciseness.

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 zero-parameter tool, the description covers the basics: what is returned and two key attributes. But it leaves important context ambiguous, such as whose sessions are listed, what 'spent' means exactly, and how this relates to sibling tools. Without an output schema or annotations, these gaps make the description merely adequate.

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 an empty schema, so there is no parameter semantics for the description to add. The schema already fully covers the parameter surface with 100% coverage. A baseline of 4 is appropriate because nothing is missing.

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 indicates that the tool returns every session along with spend amount and live status. Though it lacks an explicit verb, the tool name plus 'Every session' makes the enumeration operation unmistakable. It is clearly distinct from siblings like create_session, revoke_session, and get_balance.

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 gives no guidance on when to use this tool versus sibling alternatives such as history or get_balance. It also does not clarify scope, such as whether sessions belong to the current user or all users, or what time range is covered. The agent is left to infer appropriate usage.

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