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

With no annotations, the description carries the full burden. It usefully discloses that this performs a live TLS handshake from the socket and states the x402 price ($0.02/call, USDC on eip155:8453), which is real operational context. It says nothing about failure modes (unreachable host, handshake timeout, expired cert handling), rate limits, or what payment/auth setup is required before the call can succeed.

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-field inventory, then usage, then price — a sensible order with little waste. The middle sentence 'when an agent needs to cert details, chain, expiry' is grammatically broken, a minor blemish on an otherwise tight three-sentence structure.

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?

No output schema exists, and the description compensates well by listing the fields returned. No annotations exist, and the live-handshake plus pricing disclosure covers the essentials. Remaining gaps are error behavior and port defaults, which are real but modest for a two-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?

Schema description coverage is nominally 100%, but the schema descriptions are bare stubs ('Port', 'Domain'), so the description carries the meaning. It adds no parameter detail — notably no mention of a default port (443), even though 'port' is required, which is the one thing an agent would most likely need clarified.

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 (inspect) and resource (live TLS certificate) and enumerates the returned fields — subject, issuer, SAN, validity, expiry, protocol, cipher, chain length. That scope implies broader coverage than the near-twin security_ssl_expiry, but the sibling is never named, so an agent must infer the boundary.

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 clear context: 'the definitive check an agent should run before trusting an API endpoint' and 'when an agent needs cert details, chain, expiry — straight from the socket'. No exclusions or named alternatives (e.g. security_ssl_expiry for expiry-only checks), so it stops short of full when/when-not guidance.

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