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

Adds rich context beyond annotations: the slot becomes free, Cal.com syncs and emails the customer, demo key is a dry run, and enumerated error codes (404/409/400). Notably reconciles the 'destructiveHint: true' with 'idempotentHint: true' by explaining re-cancel returns 409.

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?

Front-loads the action and id source, then layers call preconditions, side effects, errors, and return shape in tight, well-ordered sentences. No filler.

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?

Covers trigger conditions, side effects, external integration, dry-run behavior, error semantics, and return shape for a single-param mutation with no output schema. Nothing essential is missing.

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 100% and the 'id' description already documents it as the UUID from book_appointment, so the schema does the heavy lifting; the description merely reiterates provenance.

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?

States a specific verb and resource ('Cancel ... bookings') and anchors it to the 'id' from book_appointment, clearly distinguishing it from booking/list siblings.

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?

Gives explicit preconditions ('only call after the customer has clearly asked to cancel that specific booking') and routes rescheduling to cancel + list_open_times. No explicit when-not-to-call beyond that, but strong for a single-purpose tool.

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