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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, but the description adds valuable context beyond that: it specifies the consultation length (45-minute), the payment model (agent-paid), and enumerates the exact operations it will not perform (quote, booking, order, payment). This gives the agent a precise behavioral contract without contradicting 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 exceptionally concise: two sentences that front-load the core purpose and immediately follow with a side-effect guarantee. Every word earns its place, with no redundant filler or repetition of schema information.

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 simplicity (a read-only availability check), the description is fully complete. It states what it reads, the specific consultation type, and what it does not do. An output schema exists, so return values need not be described. The context signals and sibling tools indicate a decision tree where this tool is clearly the safe, non-committal availability check.

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 input schema provides 100% coverage with descriptions for all three parameters (from, to, timezone). The tool description itself does not add parameter-specific information, but since the schema fully documents them, the baseline of 3 is appropriate. No extra meaning is needed.

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: 'Read live Cal.com availability for the 45-minute agent-paid Legal Fournier consultation.' This specifies the verb ('Read'), the resource ('live Cal.com availability'), and the scope, making it unmistakable. It also distinguishes itself from siblings by explicitly stating it never creates a quote, booking, order, or payment.

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 provides clear context for when to use the tool: checking availability without performing any side effects. It explicitly states 'This tool never creates a quote, booking, order, or payment,' which is a strong when-not usage signal. However, it does not name alternative tools for booking or creation, so it lacks the full 'alternatives' dimension.

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