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

Annotations already declare readOnlyHint=true, so the safety profile is covered, but the description adds nothing behavioral beyond restating the HTTP route: no indication of what happens on a missing/invalid id, no auth or rate-limit context, no hint at the returned shape. For a read tool with generous annotation coverage the bar is low, yet the description contributes essentially no added context.

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?

Two short sentences, the purpose front-loaded before the route, with no filler. Every clause earns its place.

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?

A simple read tool whose annotations cover safety and whose schema fully documents both parameters, so little is required. However, with no output schema there is no description of what an appointment record contains or how errors surface, leaving a modest gap for an agent consuming the result.

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%, with both 'id' (path param) and 'subdomain' (defaults to NEXHEALTH_SUBDOMAIN) documented in the schema, so baseline 3 applies. The description adds no format or constraint detail beyond the schema.

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 (fetch) and resource (a single appointment by id), and the word 'single' distinguishes it from the sibling nexhealth_list_appointments. It stops short of naming that sibling explicitly, but an agent can tell what it does without opening the schema.

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?

Usage is implied by 'by id' — you call it when you already have an appointment id — but there is no explicit when-to-use guidance and no mention of alternatives like list_appointments or search paths. Minimum viable routing information.

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