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

Annotations already declare idempotentHint=true and destructiveHint=false, and the description reinforces that with concrete behavior: an already-paused heartbeat succeeds without toggling. It also discloses a scope constraint not encoded anywhere else — the disabled flag is untouched — which matters for a mutation tool. Return payload is not described, but with no output schema that is a minor omission.

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 tight sentences: operation and scope first, then the idempotency caveat, then the boundary with the disabled flag and the alternative tool. No filler or restatement of the title.

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?

For a single-parameter mutation with no output schema, the description covers scope, idempotent behavior, side-effect boundaries, and the sibling that reverses it. The only missing piece is confirmation of what a successful call returns, which is minor given the low complexity.

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 property description already explains that the value is the external GUID returned as Id by HeartbeatList. The description adds only the qualifier that the target must be non-deleted, so it neither compensates for nor meaningfully extends the schema — 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?

The description states a specific verb and resource (set the paused flag on a heartbeat) plus scope (within the authenticated organization, non-deleted heartbeats only). Naming HeartbeatResume as the inverse makes it distinguishable from the sibling tools without opening any 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?

It clearly routes the inverse operation (clearing the paused flag) to HeartbeatResume and warns that this tool does not touch the disabled flag, which prevents a plausible misuse. It stops short of an explicit 'use this when you want to suppress alerting' statement, but the context for selecting it is unambiguous.

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