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

The description goes well beyond the annotations: 10-minute rechecks for up to 48 hours, exactly one email to the account address, four termination conditions, idempotent re-invocation, and 'nothing is applied to anyone's DNS'. That is strong disclosure and consistent with readOnlyHint=false and destructiveHint=false, but the write-ish server-side state creation implied by readOnlyHint=false is only explained indirectly rather than stated.

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?

Front-loaded with the when-to-use condition and free of filler, but it is one long paragraph packing lifecycle, idempotency, account requirements and return behavior together. Splitting the notification triggers from the argument guidance would make it easier to scan.

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?

Even though an output schema exists, the description covers the non-obvious operational facts an agent needs: no email address may be requested, a linked account is required, the watch is per signed-in user, and watch.note must be relayed. Nothing material 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%, so the baseline is 3, but the description adds genuine routing value: 'same arguments as check_record' and the conditional instruction to pass expected_value when publishing a specific value, which the schema only implies. It does not add format details for host/domain beyond what the schema already documents.

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 and resource: it 'starts a free watch on ONE record for the signed-in user' and rechecks with 'the same verdict as check_record', which directly separates it from the sibling check_record and from check_propagation. An agent knows exactly what this creates without opening the 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?

Gives an explicit trigger ('when the user asks to be told when a DNS change they are making has finished'), names the sibling whose semantics it mirrors, and spells out when nothing is started: already-live records, non-answering nameservers, lookup faults. It also pre-empts the duplicate case by saying a repeat request returns the running watch.

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