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

Annotations already declare readOnly/openWorld, and the description goes well beyond them: it discloses data provenance (cached SSL Labs report, not a live scan), the failure mode for unscanned hosts, and the billing model (fixed USDC price via x402, no charge on failure). These are exactly the operational details an agent needs before invoking.

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?

Front-loads the returned data, then the read-only precondition, then pricing. The first sentence is dense with stacked parentheticals but each clause conveys a distinct field, so little is wasted.

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?

An output schema covers return structure, and the description fills in source, failure behavior, and cost — everything needed to decide and invoke correctly for a single-parameter read tool.

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?

Only one parameter (host), and schema coverage is 100% with a host-name example already in the schema, so the schema carries the parameter burden. The description adds no format or validation detail beyond what the schema states, making baseline 3 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?

States precisely what is returned: TLS versions a host accepts (with deprecation flags), cipher-suite strength, per-protocol suite counts, weak-suite detection, and forward-secrecy status. This is specific enough to separate it from neighbors like security_ssl_cert_chain (certificate chain) and security_tls_alpn_detector (protocol negotiation) without opening a schema.

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?

Gives a clear precondition — it reads only existing cached Qualys SSL Labs reports, and a never-scanned host yields a retry error — which tells the agent when the call will fail. It does not, however, explicitly name alternative sibling tools for related TLS checks or state exclusion conditions.

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