diagnose_domain

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

Annotations indicate readOnlyHint, destructiveHint false, idempotentHint, openWorldHint. Description adds specifics: fetches domain, inspects DNS records, reports status, and gives fix steps, all consistent with read-only, non-destructive behavior, adding value beyond annotations.

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?

Three sentences: a concise summary, one detailing actions, and one providing usage context. No redundancy, every sentence adds value, and key info is front-loaded.

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?

Given the single required parameter and no output schema, the description adequately explains what the tool does and what the agent can expect (reports status and fix steps). Annotations cover safety, making this complete for its complexity.

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?

Only one parameter 'id' is fully described in the schema (Domain ID from list_domains). The tool description does not add extra meaning beyond that, but schema coverage is 100%, so baseline 3 is appropriate.

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?

Description clearly states the tool performs deep DNS/verification diagnosis for a sending domain. It specifies inspecting DNS records (SPF, DKIM, DMARC, MX, Return-Path) and reporting status with fix steps, distinguishing it from siblings like get_domain or verify_domain.

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 when sending fails with 'domain not verified' or before going live, giving clear context. However, it does not name alternative tools for other scenarios, leaving some ambiguity.

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