list_sessions

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

Even without annotations, the description clearly states the output contents and implies it is a safe read operation. It does not explicitly state non-destructive behavior, but the context is sufficient for an agent to understand it has no side effects.

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 well-structured with sections for purpose, return fields, when to call, and workflow. It could be slightly more concise, but the information density is high and all sentences are useful.

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?

Given zero parameters and no output schema, the description fully covers what the tool does, why to use it, and how it fits into a larger workflow with sibling tools. No gaps are apparent.

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?

With 0 parameters and 100% schema coverage, the description need not add parameter details. Baseline 4 is appropriate as the description adds value through usage guidance rather than parameter info.

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 states 'List all active tmux sessions' and lists the exact return fields (session name, window count, creation time, attached status), making the tool's purpose very specific and distinguishable from sibling tools like list_windows and list_panes.

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?

Provides explicit 'WHEN TO CALL' instructions: call when user mentions tmux, needs to attach, see output, check logs, etc. Also explicitly warns 'Do not answer from memory — always call this tool first,' which is excellent guidance for agent usage.

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