peers

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

With no annotations, the description carries the full burden. It discloses that the listing is a live snapshot ('live', 'names change and sessions come and go') and enumerates the state values (idle | busy | unreachable), so an agent understands results may be stale after the call. It implies read-only behavior but doesn't explicitly state lack of side effects or error conditions, which keeps it a step below perfect.

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?

Three short sentences, each with a distinct job: purpose, return values, and usage timing. It front-loads the core action, uses a colon to attach the rationale, and contains no filler or redundancy.

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 list operation with no output schema and no annotations, the description is remarkably complete: it specifies what is returned, the meaning of state, and why to call it before send_peer. Nothing essential for calling it correctly is missing.

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 an empty schema, so there is nothing to document. The baseline of 4 for 0 params applies. The description instead provides semantic value about return fields, which is helpful but not parameter-related.

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' with a specific resource ('live Claude Code sessions on this machine that you can message'), then enumerates the return payload fields and state values. This clearly differentiates the tool from siblings send_peer (sending to a peer) and message_log (reading message history).

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 last sentence explicitly instructs 'Call this before send_peer' and explains why: 'names change and sessions come and go.' This is direct, actionable guidance tied to the key sibling tool, with no ambiguity about when it should be invoked.

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