mailX tools

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

Annotations already provide readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true, covering safety and idempotency. The description adds valuable context by specifying that it returns 'all TXT records' and listing common content types (SPF policies, verification tokens, DKIM keys), which helps the agent understand what to expect beyond the basic read operation.

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 concise sentences that are front-loaded with the core purpose. Every word earns its place by clarifying the scope (all TXT records) and providing examples of content, with no redundant or unnecessary information.

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 simple lookup tool with rich annotations (read-only, non-destructive, idempotent, open-world) and full schema coverage, the description is reasonably complete. It adds context about TXT record content, though it doesn't specify output format or error handling, which is acceptable given the straightforward nature of the tool and lack of output schema.

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% with a single well-documented parameter (domain_name). The description doesn't add any parameter-specific information beyond what the schema already provides (e.g., no additional constraints or examples). This meets the baseline of 3 when schema coverage is high.

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 specific action ('Look up all TXT records for a domain') and distinguishes it from siblings by focusing exclusively on TXT records, unlike other tools that check SPF, DMARC, DKIM, or perform general DNS lookups. The examples of TXT record content (SPF policies, verification tokens, DKIM keys) further clarify the purpose.

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 implies usage for retrieving TXT records, but doesn't explicitly state when to use this tool versus alternatives like dns_lookup (which might return all record types) or specific check tools (spf_check, dkim_check). No exclusions or prerequisites are mentioned, leaving some ambiguity about tool selection.

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