list_peers

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

Annotations already declare readOnly, openWorld, and non-destructive, so the safety profile is covered. The description adds domain context beyond that: 'usage per window (one account's headroom is not another's)', agent_tokens with 'no limit known', and this_computer_sessions meaning 'your other local sessions'. It does not cover refresh/freshness or ordering, keeping it at a solid 3.

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?

A single dense sentence that front-loads the resource and then lists fields with parenthetical clarifications. It is efficient, though the run-on field enumeration with embedded asides makes it slightly harder to scan than a structured list.

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?

With no output schema and no parameters, the description must explain what comes back, and it does enumerate the key returned fields (device_id, owner, online, agents, sessions, usage, agent_tokens, this_computer_sessions). This is sufficient for a zero-arg listing tool, though freshness/ordering of the data is unstated.

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 the baseline is 4. Evaluation instead falls on the field semantics the description supplies for the return shape, which are handled under behavioral and completeness dimensions.

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 identifies the resource precisely ('Teammates' computers') and enumerates the returned fields, so an agent can tell this lists peer devices rather than tasks or messages. It also cross-references send_message's target_device, implicitly distinguishing it from siblings. It lacks an explicit verb like 'list', but the intent is unambiguous.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no named alternative. The only implicit hint is that device_id is 'send_message's target_device', which suggests a workflow but is framed as field clarification rather than usage direction.

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