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

Goes well beyond the annotations: explains that re-adding an existing domain returns the row instead of erroring (concrete idempotency semantics), that nothing is written to real DNS by this tool, that a human publishes every record, and that record strings must be echoed verbatim. It also instructs relaying guidance.note for edge cases such as Automatic DMARC.

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 purpose and return shape, then constraints in priority order. It is dense but nearly every clause carries an operational rule; the long single paragraph is the only mild readability cost.

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 supplies the workflow context an agent actually needs: account prerequisite, fallback tool, verbatim-record rule, approval gate, and note-relay instruction. Nothing required to call it correctly 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 description coverage is 100% and the single `domain` parameter is thoroughly documented there, including the registrable-domain and not-found rules. The description adds no new detail about the parameter itself, so the 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 and resource ('Add a domain to the signed-in user's DNS Doctor monitoring') and immediately describes the return payload (ownership-check TXT record, hosting provider, guide link, apply URL). This clearly separates it from read-only siblings like list_my_domains, get_domain_records and check_domain_verification.

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?

Names the alternative tool explicitly and the exact condition that switches to it: 'Needs a linked DNS Doctor account: until the human has one, or if the host's connect prompt fails, use start_monitoring_signup and print its link instead.' It also states the prerequisite (human approval) before any of the agent's own DNS tools are used.

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