analyse_spf

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

With no annotations provided, the description carries the behavioral disclosure burden. It discloses the analysis scope (full include tree, DNS lookup count, authorized senders) and specific misconfigurations it flags (multiple SPF records, +all). This is substantive enough for an analysis tool, though it does not mention network behavior or rate limits.

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 exactly two sentences. The first sentence front-loads the primary action and enumerates specific checks. The second sentence provides direct use cases. Every clause adds value, with no redundant filler.

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 analysis tool with no output schema, the description explains the main behaviors and common triggers for use. It does not describe the exact output format, but the listed deliverables (lookup count, authorized services, flags) give a sufficient mental model for an agent to decide invocation.

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?

The input schema already has 100% coverage on the single 'domain' parameter, including the example and instruction to exclude scheme/path. The description restates that it analyzes a domain's SPF record but does not add extra parameter-level detail beyond what the schema provides, so the baseline 3 applies.

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 opens with a specific verb+resource: 'Analyse a domain's SPF record' and then lists concrete capabilities (resolve include tree, count DNS lookups, identify authorized senders, flag misconfigurations). This clearly distinguishes it from sibling tools like scan_domain and check_tls by focusing exclusively on SPF analysis.

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 gives explicit use cases: 'Use this for SPF PermError, "too many DNS lookups", or to find out which providers can send mail as a domain.' This provides clear context for when to choose this tool, though it does not mention when not to use it or name any alternative tools.

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