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

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), lowering the bar. The description adds genuinely useful behavioral context beyond that: empty results are a valid outcome, not an error, and 'presence' has a domain-specific meaning that excludes being in bed. These are the kind of non-obvious behaviors agents need to know.

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, zero filler, and the most important facts are front-loaded: the endpoint, the filter, and the two non-obvious behavioral caveats. Every sentence earns its place.

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 a rich output schema, 100% schema parameter coverage, and safety annotations, the package is nearly complete without any return-value explanation. The only gap is the absence of an explicit pointer to the 'peers' sibling for unfiltered lists, which would make agent routing fully unambiguous.

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?

Schema description coverage is 100%, so the schema fully documents all four parameters and the baseline of 3 applies. The description does not add parameter-level detail, though it does reveal the implicit 'present=1' query filter that shapes the request, which is a minor bonus.

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 gives a specific verb and resource ('GET /api/peers?present=1') and defines the scope precisely: 'Only present peers.' This implicitly distinguishes it from the sibling 'peers' tool (all peers vs. present-only peers), and the added domain rule 'A bed is not presence' sharpens the meaning further.

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 implies when to use it — when you need only present peers — and provides useful semantic guidance ('Empty is allowed', 'A bed is not presence'). However, it never explicitly names the alternative 'peers' tool or states a when-not condition, so routing between siblings is left to inference.

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