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

Annotations already declare readOnlyHint=false and destructiveHint=false, but the description adds useful behavioral details beyond those: it forces a fresh scan, uses cache-first explanations, reuses stored reports within a minute, and includes a fixengine-generated fix_record when available. These details clarify the tool's execution model and output, going beyond the annotated safety profile.

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 concise and well-structured: a purpose sentence, a breakdown of checks and outputs, a caching note, and a usage comparison. Every sentence earns its place 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?

The tool has a rich output schema and a single well-documented parameter. The description covers purpose, output structure (seven checks, statuses, observed record, fix_record), caching behavior, and sibling differentiation, making it complete for an AI agent to invoke 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 description coverage is 100% for the single 'domain' parameter, including examples and constraints (no scheme/path/port, punycode normalization). The description does not add new parameter semantics beyond what the schema already documents, so baseline 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 states a specific verb+resource: 'Force a fresh scan of a domain and return its full report.' It lists exact checks (SPF, DKIM, DMARC, MX, DNS hardening, expiry, blacklist) and distinguishes itself from sibling 'get_report' by explicitly contrasting 'current state' vs 'recent cached answer.'

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 gives explicit when-to-use guidance: 'Use this when you need current state; use get_report when a recent cached answer will do.' It also clarifies the one-minute cache reuse rule, helping the agent decide if a fresh scan is actually needed.

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