list_sessions

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

With no annotations provided, the description bears full responsibility for disclosing behavioral implications. 'List active sessions' only states the action and object, offering no detail on return format, pagination, filtering, side effects, or permission requirements. It adds no behavioral context beyond what the tool name implies.

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, short sentence with no wasted words, making it concise. It does, however, border on under-specification by providing only 'active' as a qualifier, but for a simple list tool it is efficient and not overly verbose.

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?

Despite the tool's simplicity, the description lacks important context given the sibling tool 'tmux_list_sessions'. It does not clarify whether 'sessions' refers to tmux sessions or others, nor does it explain what 'active' means or what the output includes. With no output schema, the description alone is insufficient to fully understand the tool's scope.

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 trivially 100%. Per the scoring guidelines, 0 params warrants a baseline of 4. The description correctly adds nothing about parameters because there is nothing to explain; it does not mislead or omit necessary parameter information.

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 'List active sessions' clearly states the verb 'list' and the resource 'active sessions', making the core purpose understandable. However, it does not distinguish this tool from the sibling 'tmux_list_sessions', which could also list sessions, creating ambiguity. Thus it lacks sibling differentiation.

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 like 'tmux_list_sessions' or 'open_session'. There is no mention of context, prerequisites, or exclusions. It merely states the function without any usage direction.

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