Session List Tool

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

The readOnlyHint annotation already establishes this is a safe read, so the description's contribution is limited to clarifying that results are current sessions local to this host. It adds modest context but nothing about freshness, ordering, or handling of remote/SSH sessions.

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?

Front-loaded and short, with the purpose in the first clause. The trailing "Returns: List of sessions with count" duplicates information already covered by the output schema and could be dropped.

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 no parameters, a readOnly annotation, and an output schema present, the description covers everything an agent needs to decide and invoke correctly. Only minor gaps (scope of sessions counted) remain.

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; there is no parameter semantics for the description to explain.

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 and resource ("List logged-in sessions") and adds scope ("who's on this box right now"), which is clearly distinct from the systemd unit/timer/journal siblings. It does not explicitly name alternatives, but the domain difference is obvious.

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?

Usage is only implied by the phrase "who's on this box right now" — an agent can infer this is for checking current interactive logins rather than history. There are no explicit when-to-use/when-not conditions or named alternatives.

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