check_dane

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

Discloses the exact process (resolving MX hosts, looking up TLSA records at _25._tcp.<mx-host>, verifying certificate binding). Annotations already indicate readOnlyHint and idempotentHint, and the description adds detailed behavioral context without contradiction.

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?

Four concise sentences, each serving a distinct purpose: main action, process detail, usage guidance, sibling reference. No unnecessary 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?

Given the tool's complexity, the presence of a output schema (not shown but indicated), and clear annotations, the description covers purpose, process, usage context, and sibling distinction completely.

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 coverage is 100%; description does not add additional explanation beyond what the schema provides for each parameter. Baseline score of 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?

Description clearly states it checks DANE/TLSA for SMTP at port 25, describes the process of resolving MX hosts and looking up TLSA records, and distinguishes from the HTTPS variant by explicitly naming check_dane_https for HTTPS.

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?

Explicitly says when to use: 'Use when asked if SMTP connections are protected by DANE/TLSA pinning.' Also provides alternative for HTTPS: 'For HTTPS DANE at port 443, use check_dane_https instead.'

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