TLS certificate

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

Annotations already provide readOnlyHint=true and destructiveHint=false, covering safety. The description adds valuable behavioral context by disclosing that failed chain verification returns valid=false with the reason, which goes beyond the structured annotations. It also lists the negotiated protocol, a behavioral output. No contradiction with annotations.

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 two sentences with zero wasted words. The primary purpose and specific outputs are front-loaded, and the failure behavior is appended as a separate sentence. It is efficient and well-structured.

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?

The tool has an output schema, so return values are documented there and the description need not repeat them. The description covers the essential behavioral aspects (what it inspects, failure handling) and the annotations cover safety. Complexity is low (two parameters), and nothing an agent needs to call it correctly is missing.

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 100% (both host and port have descriptions), so baseline is 3. The tool description does not add further parameter semantics beyond what the schema already provides. It mentions 'host' implicitly but does not elaborate on format or constraints beyond the schema's examples.

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 uses a specific verb ('Inspect') with a clear resource ('TLS certificate a host serves') and enumerates the exact fields returned (issuer, subject, SANs, validity window, days until expiry, negotiated protocol). It also states failure behavior. This clearly distinguishes it from sibling tools (dns_lookup, http_probe, ip_rdap) which cover DNS, HTTP, and IP info respectively.

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?

The description implies when to use the tool (when TLS certificate details are needed) and its sibling set makes alternatives obvious. However, it does not explicitly state when not to use it or name alternatives as the calibration example does. The domain is clear enough that an agent can infer correct usage without exclusions.

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