tls_cert_check

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

Without annotations, the description carries the full burden. It explicitly states 'Read-only', lists the output JSON structure with all fields, and mentions a specific error ('openssl_not_available'). This is sufficient for a simple tool, though it could detail side effects (none) or behavior on unreachable instances.

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 plus a structured note on output and errors. It is front-loaded with the core action and immediately clarifies the tool is read-only. Every sentence serves a purpose: what it does, its output, and an error case.

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 one parameter, no output schema, and simple behavior, the description covers the essential: scope (certbot+nginx/apache configs), output format, and error. It lacks details on instance lookup failures or rate limits, but these are minor for a read-only diagnostic 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?

The only parameter 'instance_id' has a schema description ('Instance ID or name.'). The tool description adds that the check is 'on one instance', but does not explain how to obtain the ID or name. Since schema coverage is 100%, baseline 3 is 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?

The description clearly states the verb 'Discover' and resource 'TLS certificates on one instance', specifying the scope (certbot live dirs + nginx/apache configs). It distinguishes from siblings like check_status or get_server_info by focusing on certificate discovery and expiry reporting.

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 does not explicitly mention when to use or alternatives, but it clearly indicates the tool is for checking TLS certificates on a single instance among a set of general and monitoring tools. The read-only nature and output format provide implicit guidance. A more explicit exclusion of other tools would improve clarity.

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