list_sessions

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

Annotations already set readOnlyHint=true, and the description reinforces this by listing read-only output fields (PID, Blocked, Runtime). It adds debugging context (e.g., 'Blocked: true' means waiting for input) without contradicting any annotations. The description is fully transparent about the tool's behavior.

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 bullet points for clarity. It is mostly concise, though the last sentence about reference phrasing could be considered extraneous. The main action is front-loaded, and the additional details are relevant and grouped logically.

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 lacking an output schema, the description fully explains what the tool returns (PID, Blocked, Runtime) and provides usage context for debugging. It covers all necessary aspects for a simple list tool, making it complete for effective invocation.

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 no parameters, and schema description coverage is 100%. The description correctly does not add parameter information because none exist. Baseline 4 is appropriate as the description adds no surplus value for parameters.

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 the tool's purpose: 'List all active terminal sessions.' It specifies the resource (terminal sessions) and the action (list). The details about session status and debugging REPLs further refine its purpose. It distinguishes itself from sibling tools like list_processes by focusing on terminal sessions and their specific status fields.

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 explicit guidance on when to use the tool, such as verifying sessions are running before sending input and identifying stuck processes. However, it does not explicitly exclude scenarios or compare with sibling tools, which would enhance clarity. The tips are practical and context-aware.

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