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

The annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true. The description adds valuable behavioral context about the two modes (recurring vs one-off) and clarifies that the tool adds an availability window, which is consistent with the 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 concise, using two sentences to convey the purpose and the two usage modes. It is front-loaded with the core action and avoids redundant or verbose language.

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 tool's complexity (7 parameters, two modes) and the presence of an output schema, the description provides sufficient context for invoking the tool correctly. It covers the key distinction between recurring and one-off availability, though it does not mention the 'type' parameter (available/blocked) which is documented in the schema.

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?

While the input schema has 100% parameter coverage, the description adds semantic value by explaining the combined usage of dayOfWeek + isRecurring for weekly schedules versus date for one-off changes. It also reinforces the meaning of memberId as companyMembers.id.

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 tool's function with a specific verb ('Add') and resource ('an availability window for a staff member'), explicitly referencing companyMembers.id. This distinguishes it from the sibling tool set_resource_availability, which handles resource availability.

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 gives clear usage context by explaining when to use day-of-week + recurring versus a specific date, which guides the agent in choosing the right parameters. It does not explicitly mention alternatives or exclusions, but the staff member reference implies the division from resource availability.

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