email_check_spf

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It adds substantial detail: parses mechanisms/qualifiers, follows include chains, counts DNS lookups against RFC 7208 max 10, and flags specific misconfigurations. This goes beyond simply fetching a record, though it doesn't discuss error handling or exact return format.

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 each detail (mechanisms, include chains, DNS lookup counting, misconfiguration flags) is relevant and non-redundant. No filler words or repetition of the tool name.

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 lack of an output schema and the tool's moderate complexity, the description explains the main capabilities well (parser, lookup counting, misconfiguration detection). It omits explicit return structure or edge-case behavior (e.g., no SPF record), but the description is sufficient for an agent to understand what the tool does and invoke it correctly.

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 coverage is 100%: the only parameter 'domain' is described as 'The domain to check SPF records for (e.g. example.com)'. The description adds no new semantic information about the parameter beyond what the schema already provides, so the baseline score of 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?

The description clearly states the tool checks SPF records for a domain, with a specific verb ('Check') and resource ('SPF record'). It distinguishes from sibling email tools like email_check_dkim and email_check_dmarc by explicitly naming SPF and listing detailed analysis behaviors (parses mechanisms, follows include chains, counts DNS lookups).

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 context is clear: use this tool to check SPF configurations for a domain. However, it does not explicitly mention alternatives or exclusions, such as when to use email_spf_enumerate or other email check tools instead. Despite that, the operational details imply a focused use case, making it easy for an agent to select.

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