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

Annotations already declare idempotentHint=true and destructiveHint=false, and the description adds substantive context beyond them: it costs no monitors, repeats with the same plan id return the first result, and it returns the watch with its starting values. It also clarifies that removal/change is not handled here, which is useful boundary information.

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, front-loaded with the trigger condition, then return behavior, cost, idempotency, and exclusions. Every sentence earns its place.

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 two-parameter tool with full schema coverage and safety annotations, the description covers the key behavioral facts an agent needs: prerequisite confirmation, return content, no monitor cost, idempotent repetition, and the exclusion for removal/change.

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 both plan_id and confirm are already documented in the schema. The description adds the useful idempotency detail that the same plan id returns the first result, but it does not add further meaning for the confirm parameter beyond the schema's instructions.

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+resource (add DNS watch) and immediately ties it to the prerequisite plan_dns_watch plan. It also distinguishes itself from the removal/change path, so an agent can tell it apart from sibling tools 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?

Explicitly says to use this only after the user has confirmed a plan_dns_watch plan, and explicitly excludes removing or changing a watch by naming the alternative (the site's DNS page). This covers when to use it, when not to, and where else to go.

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