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

Beyond the readOnly/idempotent annotations, the description discloses a meaningful behavioral trait: the return is a verified status with a date when Foundations has published one, otherwise it falls back to the website's scheduling statement. That fallback-branch disclosure is exactly the kind of context annotations can't carry. It stops short of describing error conditions or how stale a 'verified' status can be.

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?

Three tight sentences, front-loaded with the scope and then the return semantics. The phone/booking clause is useful routing but slightly buried at the end; nothing is wasted overall.

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, the description carries the return-value burden and does so: it explains both possible response shapes (verified status + date, or website scheduling statement) and the per-counselor limitation. An agent has everything needed to call it and interpret 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 coverage is already 100% with an enum, so the bar is a baseline 3. The description earns a bump by stating the parameter is optional and that omitting it yields practice-level (all-office) availability, which clarifies the default behavior rather than repeating the enum.

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 first sentence names a concrete resource (practice-level availability) and scope (new clients, optionally one office or online), so an agent immediately knows what is returned. It doesn't explicitly contrast with siblings like find_counselors or get_counselor, but the resource is distinct enough that confusion is unlikely.

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 gives clear routing: this returns practice-level (not per-counselor) availability, and when no published data exists, openings must be confirmed by phone or the booking link. The main gap is that it doesn't name the sibling tool (get_counselor) as the alternative for counselor-specific questions, so an agent must infer that.

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