domain_fetch_ssl_certificate_chain

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

The description adds behavioral context beyond annotations: it declares 'Read-only. No side effects. Idempotent.' (matching annotations), mentions a 4-hour cache, and specifies the data source (crt.sh Certificate Transparency). It also describes the return fields (issuer, subject, validity period, SANs). 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 well-structured with front-loaded purpose, parameter details, usage guidance, and fallback. Every sentence adds value, but it is slightly verbose due to the feedback instruction. Still efficient for the information conveyed.

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 simplicity (one parameter, output schema present), the description covers all necessary aspects: purpose, parameters, return fields, usage context, alternative, data source, caching, and a feedback mechanism for gaps. No missing information.

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%, providing a baseline of 3. The description adds meaningful clarification: 'Domain name without protocol e.g. github.com. Required. Does not support IP addresses or wildcard domains.' This adds constraints not fully captured by the schema description, earning a 4.

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 the action ('Fetch SSL certificate history') and the resource ('from Certificate Transparency logs'). It distinguishes itself from sibling tools by explicitly naming domain_fetch_domain_rdap as an alternative for registration data. It also specifies limitations (no IPs/wildcards), which further clarifies its scope.

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?

Provides explicit guidance on when to use ('detect unexpected certificate issuance or audit certificate history') and when to use an alternative ('Use domain_fetch_domain_rdap instead when you need registration data'). Also includes fallback instructions for if the tool does not suffice, guiding the agent to report feedback.

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