list_sessions

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

With no annotations present, the description carries the full burden of behavioral disclosure. It clearly states the action is a read-only listing and highlights the running-state information, which is useful. However, it omits details such as whether terminated sessions are included, what fields are returned for each session, or any potential side effects. This is acceptable for a simple list but not fully transparent.

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, front-loaded sentence with no wasted words. It states the action, target, and key output detail ('whether they are running') efficiently. Every word adds value.

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?

The tool has no parameters, no output schema, and no annotations, so the description is the only source of context. It explains the basic purpose but leaves ambiguity about the exact return structure (e.g., session IDs, names) and whether it includes all sessions or only active ones. For a simple list tool this is a moderate gap; additional detail about the returned fields would make it complete.

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 input schema has zero parameters, so the baseline for parameter semantics is 4. The description doesn't need to explain parameters. It correctly focuses on the tool's output rather than inputs, and there is no parameter documentation gap.

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 uses a specific verb 'List' with a clear resource 'existing terminal sessions' and adds the meaningful detail 'whether they are running.' This distinguishes it from sibling tools like run_command and command_status, which handle execution and status of individual commands rather than session enumeration.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention when to prefer list_sessions over command_status or other siblings, and gives no context about prerequisites or typical use cases. The implied usage is to list sessions, but no explicit comparisons or exclusions are provided.

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