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

Beyond the annotations, it discloses important behavioral details: setup returns DNS instructions without editing DNS or enabling measurement, existing subdomains cannot be replaced, pending updates have a two-minute lease, and choices apply to future emails without granting recipient consent. It also warns that opens and clicks may include proxies or scanners, which is valuable operational context. No contradiction with the annotations is present.

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?

The description is dense but front-loaded and each sentence carries operational information, with no obvious filler. It is somewhat heavy in clauses, but that is justified by the multi-step workflow and the need to convey permissions, retry behavior, and DNS constraints.

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 complex multi-action configuration tool with no output schema, the description supplies the workflow, prerequisites, constraints, safety caveats, and a MCP guide resource. An agent has enough context to understand the setup-verify-save sequence and the conditions under which save is permitted.

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?

With schema coverage at 67%, the description adds meaningful semantics beyond the schema: all actions require domainId, expectedRevision, and a stable requestId; setup additionally needs trackingSubdomain as one DNS label; save requires explicit clickTracking/openTracking booleans. It covers the main payload expectations well, though it does not fully enumerate every possible verify/save field.

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 names the specific resource and the three operations (setup, verify, save), and explains what each does in the email tracking measurement flow. It distinguishes this tool from adjacent email configuration/inspection tools by framing it as owner-confirmed measurement setup rather than a passive inspection or unrelated domain setup.

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 lays out a clear ordered workflow: run setup, add returned DNS records externally, then verify before save is allowed. It also gives key conditions and constraints, such as only dns.status verified permitting save and existing tracking subdomains not being replaceable. It does not explicitly name alternative sibling tools or state when not to use this tool, so it falls short of full when/when-not guidance.

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