dns_propagation

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

No annotations are provided, so the description fully covers behavioral traits. It discloses that the tool is read-only, requires no API key, is rate-limited, queries across 8+ resolvers, and returns per-resolver values and a consistency verdict. These details exceed what an agent would infer from the schema alone and provide a clear operational picture.

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 long, front-loading the core functionality in the first sentence and adding usage guidance and sibling differentiation in the second. Every sentence serves a purpose with no wasted words.

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?

Despite having no output schema, the description implies the return structure (per-resolver values and a consistency verdict). It also covers rate limiting, authentication, and appropriate use cases. Given the moderate complexity (2 parameters, 1 required), the description provides enough contextual detail for an agent to understand, invoke, and interpret results 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?

The input schema has 100% description coverage for both parameters (domain and type), so the baseline is 3. The tool description adds value by noting that the default type 'A' is 'the most common propagation check,' providing context beyond the schema description. This extra semantic guidance justifies a score above baseline.

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 it queries one DNS record across 8+ global resolvers and reports stale vs updated values. It uses a specific verb ('Query') and resource ('DNS record'), and distinguishes itself from the sibling tool dns_lookup by noting its focus on propagation confirmation rather than authoritative answers with SPF/DMARC validation.

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 explicitly states when to use this tool: 'Use this after changing a record to confirm worldwide propagation.' It also contrasts with the sibling dns_lookup, saying 'Use dns_lookup instead for a single authoritative answer with SPF/DMARC validation,' and mentions the tool is read-only, requires no API key, and is rate-limited.

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