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

Annotations only say readOnlyHint and openWorldHint; the description goes well beyond them by disclosing the cached-only data source, the failure mode (retry error, not a fresh scan), the exact price and payment rails (x402 on Base/Solana/Arc), and that failed calls are not charged. That is precisely the kind of cost/auth/failure context annotations cannot express.

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 what is audited and where the data comes from, then tacks on the caching constraint and pricing as separate thoughts. The field list is long but each item is load-bearing for tool selection; the sentence is dense but readable.

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 exists, so return values need not be described in prose, and the description still previews the key report fields. With one trivial parameter, full schema coverage, and explicit disclosure of caching, failure, and pricing behavior, an agent has everything needed to decide and call 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?

Schema coverage is 100% for the single required 'host' parameter, so the schema already defines it; the description adds the fixed port (443) and confirms the audit is host-scoped, which the schema does not say. Minor addition only, hence 4 rather than 5.

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 a specific verb and resource — 'HTTPS certificate chain and cipher audit for a host (port 443)' — and pins the data source ('Qualys SSL Labs' cached report'). It also enumerates the fields returned (grade, chain length, trust store, TLS versions, weak ciphers, Heartbleed/POODLE/BEAST, HSTS), which lets an agent distinguish it from siblings like security_tls_cipher_enum or security_cert_revocation_crl without opening schemas.

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 concrete when-not-to-use condition: only cached reports are read, so an unscanned host returns a retry error rather than triggering a scan — a real behavioral boundary the agent can act on. It also states the paid-call prerequisite (x402, USDC, $0.002). It does not name an alternative sibling (e.g. a live TLS enumeration tool) for hosts that were never scanned, so it stops short of full routing guidance.

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