session_list

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

With no annotations, the description carries the full burden and clearly states the tool is read-only ('List all active terminal sessions') and specifies the output fields (status, idle time). This is sufficient for a simple listing operation, though it omits potential details like permissions or whether the list is real-time.

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 of 10 words with no filler. Every word adds value: the verb, the resource, and the output specifics are all present. This is an example of ideal conciseness.

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 the tool has no parameters, no output schema, and no annotations, the description adequately covers its purpose and return content. There are no missing pieces for the agent to understand its basic function.

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 and 100% coverage, so the baseline is 4. The description adds no parameter information because none is needed; it simply describes what the tool returns without requiring any input.

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') and resource ('active terminal sessions') along with the output details ('status and idle time'). This clearly distinguishes it from sibling tools like session_create, session_send, or session_read, which perform actions on individual sessions rather than merely listing them.

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?

While the description implies that this tool is used to obtain a list of active sessions (e.g., before acting on a session), it does not explicitly state when to use it versus alternatives, nor does it provide cues such as 'use this to get session IDs for other tools'. The guidance is purely implicit from the tool name and sibling context.

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