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

Annotations already declare the write/safe/closed-world profile, so 'This is a write' earns nothing, but the description adds genuinely non-obvious context: the record is stored as an agency_events entry with fixed type/status, and notes may contain health information (a sensitivity flag an agent should surface). It misses the natural follow-on of idempotentHint=false — that repeated calls create duplicate visits.

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?

Four short sentences, front-loaded with the core action and the accepted datetime formats. 'This is a write' is filler against annotations that already say so, but overall there is little waste.

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?

With no output schema and a non-idempotent create, the definition should cover what a successful call returns or how to detect a duplicate, and it does not. The optional agencyId is left completely undocumented in both schema and description, so an agent cannot tell when to supply it.

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 80%, so parameters are largely self-documented. The description's scheduledFor guidance ('ISO-8601 datetime or Unix milliseconds') and the scheduledAt storage note restate what the schema already says, adding no new semantics; agencyId remains unexplained in both places.

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 gives a specific verb and resource ('Creates a scheduled visit for an agency client') and pins the internal representation ('agency_events type scheduled, status scheduled'), which lets an agent distinguish it from add_visit_note and list_visits without opening a 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?

It implies the usage context (creating a new visit for an existing agency client) and points at list_visits as a verification path, but never states when to prefer this over siblings like add_visit_note, nor any prerequisite such as needing a clientId from list_clients first.

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