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

Annotations already declare readOnly, idempotent, non-destructive, and open-world, so the safety profile is largely covered. The description does add real value beyond them: it clarifies that this reads venue-side lapse state and a 24h destroyed-order count on this chain, not just local session state. It doesn't discuss freshness, caching, or what an unarmed/missing session looks like.

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 front-loaded sentence that names the resource first, then enumerates returned fields in a scannable order, and closes with the read-only constraint. No filler or repetition of annotations.

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?

An output schema exists, so return structure needn't be explained, and the description still summarizes the key returned facts. With one optional parameter fully documented and rich annotations, an agent has everything needed to call this correctly.

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 coverage is 100% and the single chainId parameter is fully documented in the schema, including Base 8453. The description mentions 'on this chain' but adds no format, default, or omission semantics beyond the schema, so baseline 3 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 (Read) and resource (this wallet's dead-man heartbeat session), then enumerates exactly what is returned: armed status, ttlSeconds, activeUntil, last beat, last venue lapse-cancel, venue lapse grace, and 24h destroyed-order count. This lets an agent distinguish it from the sibling problee_orderbook_heartbeat without opening either 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?

The closing clause 'it never arms, renews, or disarms anything' implicitly routes mutation intent to the sibling heartbeat tool, which is clear context. It stops short of naming that alternative explicitly, so the routing requires a small inference.

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