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

With no annotations, the description carries the full burden and does disclose meaningful traits: it is 'Free' (cost), it performs DNS resolution of includes, and it returns records to publish rather than mutating DNS itself, implying a read-only operation. It omits failure behavior (missing/invalid SPF) and any rate limits, keeping it short of a 5.

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 tight sentences with zero filler; the cost note and the core action are front-loaded, and the trigger condition closes the description. 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 single-parameter tool with no output schema, the description supplies purpose, trigger condition, and the nature of the return value ('TXT records to publish'). Nothing needed 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 schema documents the single 'domain' parameter, so the baseline is 3. The description's phrase 'a domain's SPF record' is consistent with the schema but adds no format or validation detail beyond it.

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 transformation (replace SPF includes with resolved IP ranges) plus the concrete output (TXT records to publish). This is clearly distinguishable from siblings like inspect_domain_dns or audit_sending_domains, which inspect rather than rewrite.

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 condition: 'Use it when an SPF record is at or over the 10-lookup limit.' It does not name alternatives (e.g., inspect_domain_dns to first count lookups) or state when not to use it, but the when-to-use context is unambiguous.

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