check_subdomailing

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

Annotations already declare readOnlyHint true, destructiveHint false, and idempotentHint true, covering the safety profile. The description adds that it analyzes the SPF include chain, which is useful behavioral context beyond annotations. No additional side effects or operational traits are disclosed, but with strong annotations, this is adequate.

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 two sentences, front-loaded with the core purpose, and contains no filler. Every word adds value, efficiently conveying what, when, and the parent context.

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?

With an output schema present and 100% parameter coverage, the description needs only to clarify the tool's niche and usage context, which it does. It might have mentioned cache behavior or return format, but those are covered by the schema and annotations. Overall, it's sufficiently complete for this simple read-only tool.

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 all parameters (domain, format, force_refresh) are already well-documented with descriptions in the schema. The tool description adds no additional parameter meaning, matching the baseline of 3 for high schema coverage.

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 uses a specific verb 'Detect' and clearly states the resource: 'SubdoMailing risk' through analysis of the SPF include chain. It differentiates from siblings by focusing on dangling/hijackable subdomains in SPF includes, distinct from tools like check_subdomain_takeover or resolve_spf_chain.

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?

The description provides explicit when-to-use scenarios: 'Use when you want to know if an SPF include chain can be hijacked through a dangling domain, or to detect subdomain mailing risk hidden in SPF includes.' It also notes it's part of the scan_domain audit, giving context, though it doesn't explicitly mention alternatives or when not to use it.

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