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

With no annotations provided, the description carries the full behavioral burden and does disclose the key traits: it is a read-only DNS operation, it returns a categorical verdict plus an A–F grade and concrete reasons, and it explains the semantics of each verdict value. It omits rate limits, caching, or failure behavior, but covers the safety and output profile well.

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 verdict definitions are front-loaded and each sentence contributes — verdict semantics, the DMARC controlling factor, and the read-only note. It is dense but not padded, though the parenthetical explanation of p=none could be trimmed.

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 read-only tool with no output schema and no annotations, the description covers the return shape (verdict, grade, reasons) and the operation's nature, which is enough for correct invocation. Minor gaps like error behavior are acceptable at this 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?

Schema description coverage is 100% for the single 'domain' parameter, so the schema already documents the input. The description adds no syntax or format detail beyond what the schema provides, making the baseline 3 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 states a specific verb (judge) and resource (how easily a domain's mail can be forged), and defines the tool as a correlation of SPF and DMARC into a single verdict. This implicitly distinguishes it from single-record siblings like dmarc_check and spf_check, which an agent can tell apart without opening schemas.

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?

It explains the meaning of each verdict and notes that 'the controlling factor is DMARC', which implies usage, but it never explicitly says when to prefer this synthesized verdict over calling dmarc_check or spf_check directly. Usage is inferable rather than stated.

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