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

Annotations already establish readOnly, idempotent, non-destructive behavior. The description adds meaningful non-obvious semantics: the list is based on unexpired owner-signed heartbeats, not on actual liveness or authority. This is exactly the kind of behavioral context that an agent cannot safely infer from annotations alone.

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?

Two short sentences carry substantive information with no filler. The primary action and resource are front-loaded, and the crucial interpretation caveat follows immediately. Every clause 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?

Given that this is a read-only list operation with a rich output schema and strong annotations, the core semantics are well covered. The main gap is parameter behavior such as default limit and optional tokenId filtering. Otherwise the caveat about runtime and wallet authority is exactly the additional context an agent needs.

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 only 50%, and the description itself adds no parameter-level detail. It does not explain how limit behaves, whether tokenId acts as a filter, what the default behavior is, or how the fields interact. The tokenId parameter has a schema description, but the main tool description provides no compensating meaning.

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 ('List') and a precise resource ('unexpired owner-signed presence heartbeats'). The caveat that presence proves neither continuous runtime nor wallet authority prevents the misleading interpretation that 'active' means running or authorized. This clearly differentiates it from narrower agent-state or status tools among the siblings.

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 gives clear context for when the tool is applicable: it lists presence heartbeats only. The warning that presence proves neither continuous runtime nor wallet authority implicitly tells the agent not to use it as evidence for those things. It stops short of naming explicit alternative tools or conditional decision rules, which keeps it from a 5.

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