View active tmux sessions to identify running Claude Code instances. Use this to check session status before sending commands or starting new ones.
List active sessions.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "list"
}
}| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v1.0.18Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the burden of behavioral disclosure. 'List active sessions' conveys a read-only enumeration behavior and the filtering to active sessions, but it does not mention output format, whether inactive sessions are omitted, or any side effects. For a simple list tool this is adequate but not rich.
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 sentence with no wasted words. Every word earns its place and the core behavior is front-loaded.
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 with no output schema, the description is largely sufficient: an agent knows the action and the target resource. Some ambiguity remains about what 'sessions' refers to and what the return payload looks like, but the sibling names provide enough contextual grounding.
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 the schema coverage is 100%, so no parameter documentation is needed. The description adds nothing about parameters, but nothing is required; this matches the baseline for a no-parameter tool.
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 states a specific action (list) and resource (active sessions), making its core purpose clear. It does not explicitly differentiate itself from sibling tools, but the verb 'list' is distinct from spawn/read/send/kill.
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 implies the tool should be used when you need to view currently active sessions, but it provides no explicit conditions, exclusions, or comparison with alternatives. There is no guidance about when list would be inappropriate or when a sibling tool should be used instead.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.