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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it caps results at 100 and explicitly states this is the only verification mechanism, which is useful for an agent reasoning about side effects and reliability. It doesn't describe pagination or ordering, but for a read-only list tool with annotations, this is solid.

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 sentences, no filler, and the most important operational guidance ('use after every create or cancel') is front-loaded. Every sentence 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?

For a zero-parameter read-only tool with annotations covering safety, the description is nearly complete. It explains the result cap and the verification role. It doesn't mention return format, but there is no output schema and the tool is simple enough that an agent can infer a list of bookings. Minor gap: no mention of ordering or time horizon, but not critical.

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 tool has zero parameters, so there is no parameter semantics burden. The description's mention of 'upcoming confirmed bookings' clarifies the implicit filter, which is the only meaningful semantic context an agent needs. Baseline 4 for zero params is appropriate.

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 states a specific verb ('List'), a resource ('upcoming confirmed bookings'), and a scope ('up to 100'). It also distinguishes itself from siblings by noting it is the only way to verify a booking exists, which clearly separates it from list_available_slots and list_event_types.

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 explicit when-to-use guidance: use after every create or cancel, and use it first whenever a write returned an uncertain outcome. This is strong usage direction that tells an agent exactly when to invoke this tool versus alternatives.

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