check_tlsa_dane

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

Annotations already provide readOnly/idempotent safety, but the description adds critical behavior: it does NOT fetch or cryptographically match the live certificate, and it resolves MX hosts when no port is given. This goes beyond annotations and prevents misuse. No contradiction found.

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 a single, dense sentence that packs both behavior and usage guidance without redundancy. It front-loads the core purpose ('Read-only TLSA/DANE DNS record check') and follows with needed details. Though slightly long, it avoids redundancy and adds value with each clause.

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 absence of an output schema, the description explicitly lists the returned data (parsed usage, selector, matching type, certificate data, syntax errors, best-practice advisories). It also covers limitations and pairing context, making the tool's scope complete for an agent without extra missing pieces.

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% with descriptions for all three parameters. The description enriches semantics by explaining how 'port' interacts with tuple construction (no port -> MX host resolution; explicit port -> _<port>._<protocol>.<domain>), which is not in the schema's property descriptions.

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's a read-only TLSA/DANE DNS record check, and elaborates on behavior with/without port. It distinguishes from siblings like check_smtp_tls and lookup_dns by specifying the TLSA/DANE scope and the exact tuple construction.

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 states when to use it ('before publishing DANE records or troubleshooting DANE handover'), what it does NOT do (doesn't fetch or match live service certificate), and directs users to pair it with check_smtp_tls for SMTP certificate evidence, providing an alternative tool.

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