session_list

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

Annotations only carry readOnlyHint=true, so the description adds real value: it discloses that sessions from earlier servers/agents are addressed by name like your own, and that a closed session's logs persist on disk for a few days with an expiry shown in the listing. It does not mention pagination or result limits, keeping it below 5.

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?

Front-loaded with the value of the listing, then usage, then persistence behavior — every clause carries information. The multi-line run-on enumeration of presence fields is dense but does not waste sentences; slightly awkward phrasing keeps it from a 5.

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 parameterless, read-only listing tool with an output schema, the description covers purpose, when to invoke, cross-session addressing, and log retention. The agent has everything needed to decide to call it and how to interpret what it gets back.

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 takes zero parameters, so there is nothing to disambiguate and no compensating burden on the description. Baseline of 4 applies.

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?

States a specific verb+resource (list terminal sessions) and then enumerates the exact facets returned: state, running process, size, originator, attached humans, attach command, presence. It also distinguishes itself from sibling session_logs by noting logs persist after close. An agent can pick this over session_logs or session_create without opening a schema.

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?

Gives clear context ('worth a call at the start of a conversation' because an earlier session may still be running) and routes to the related tool session_logs. It stops short of an explicit when-not-to-use clause or a named competing call, so it lands just below a full 5.

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