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

Goes well beyond the annotations (which only give readOnly=false, destructive=false, openWorld=true, idempotent=false). The description discloses the full side-effect chain (calendar event, confirmation email with invite, Mike alerted, lead recorded), the OAuth scope 'mikefluff:booking' plus the 401-with-sign-in failure mode, rate limits (3/hour per caller, 2 upcoming per email), and the cancel/reschedule link. This is unusually rich behavioral context for a mutation tool.

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-loaded with 'SIDE EFFECT:' so the most consequential fact lands first, and nearly every clause carries distinct operational information (effects, auth, limits, cancel path). It is one dense block rather than scannable chunks, but very little is padding.

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 7-parameter, non-idempotent, open-world write tool with no output schema, the description covers the prerequisites (explicit user intent, valid slot), authentication, side effects, limits, and how the user can undo the booking. Nothing an agent needs in order to call it correctly 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%, so the baseline is 3, but the description earns more: it explains that name/email default to the signed-in INITE ID account when omitted, constrains slot to exact get_booking_slots values, and gives real meaning to the topic enum (diagnostic, automation, compliance, architect-mode) that the schema only labels 'What the call is about'. Only locale and timeZone get no extra detail from the prose.

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 with concrete scope: 'books a real 30-minute video call in Mike Fluff's calendar'. It also distinguishes itself from the get_booking_slots sibling by declaring that slot values must come from that tool, so an agent can route correctly without opening the schema.

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?

Explicit gate: 'Only call this when the user has explicitly asked to book and chosen the time.' It names the upstream dependency for valid slot values and enumerates the four topical variants, covering when-to-use and what to confirm before calling.

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