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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context by defining pause ('never alerts') and resume ('a fresh deadline'), which the annotation set does not express.

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 with the update action first, the affected fields listed parenthetically, and the pause/resume modes carrying their own definitions. No filler sentences.

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 9-parameter tool with full schema coverage and annotations covering safety, the description conveys the operation and the pause/resume meaning. Only minor gaps remain, such as whether omitted fields are left untouched (partial vs full update), and there is no output schema requiring return-value explanation.

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 each parameter is already documented in the schema. The description's parenthetical field list (name, period, grace, inbox, email_owner) maps to those parameters and ties status to pause/resume, but adds no syntax or format detail 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 set (change, pause, resume) applied to a named resource (heartbeat check) and enumerates the mutable fields. An agent can tell this is the modification tool rather than heartbeat_add/remove/status/test, though it never names those siblings explicitly.

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?

Usage is implied by the pause/resume semantics rather than stated as guidance. There is no explicit 'use this instead of heartbeat_add/remove' routing, no prerequisites, and no note on when an update is appropriate versus creating a new check.

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