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

Annotations already declare readOnly=false, idempotent=false, openWorld=true, and destructive=false. The description adds critical behavioral context beyond that: if not refreshed before expiry, every open order is closed automatically, and it gives the valid timeout range.

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?

Four short sentences, each carrying necessary information. The purpose and risk are front-loaded, followed by the timeout constraint and the refresh instruction.

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 the output schema and annotations, the description is complete enough: it explains the tool's behavior, the consequence of inaction, the parameter bounds, and the refresh alternative. Nothing essential for correct invocation 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?

Schema coverage is 100%, and the single timeout parameter is already fully described in the schema. The description repeats the 10-300 second range but adds no syntax or meaning beyond what the schema provides.

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 states a specific verb and resource ('Start a dead-man's switch') and explains the effect in the same sentence. It names the sibling tool refresh_heartbeat as the refresh path, so an agent can distinguish create from refresh without opening schemas.

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?

It clearly implies the use case: arm the switch and refresh it with refresh_heartbeat before expiry. However, it does not explicitly state when not to use it or mention cancel_heartbeat as the way to disarm it.

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