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

Annotations only declare readOnlyHint=false and destructiveHint=false, so the description carries the real burden — and it delivers the FORBIDDEN failure mode for gated settings plus the exact default values applied when arguments are omitted. It omits whether creation triggers an immediate sync run and whether the operation is idempotent, which would round it out.

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?

Purpose is front-loaded, followed by argument format, return value, defaults, then plan gates — each sentence is actionable and none is redundant. The dense plan-gate block is information an agent must have to avoid a FORBIDDEN error, so it earns its length.

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 10-parameter, deeply nested mutation tool with no output schema and no schema descriptions, the definition covers creation semantics, the calendar reference format, defaults, and plan gating well. It leaves gaps around deep settings structures and whether the new sync begins running immediately, but the essentials for a correct call are present.

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 0% and there are 10 parameters with deep nested objects, so the description must compensate. It does document the calendars {accountId, providerCalendarId} shape, several defaults, and names five nested settings keys, but the large fieldExpressions, exclusionRules, directionalSettings perPair and most copy* booleans remain unexplained in both schema and description.

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 (Create) and resource (sync process) plus the structural constraint of 'spanning two or more calendars'. An agent can distinguish it from get_sync, update_sync, trigger_sync, and delete_sync without opening any 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?

Gives a concrete prerequisite pointer ('use list_available_calendars to discover them') and extensive plan-tier gating rules that condition when certain settings can be used. It does not, however, state when to prefer create_sync over update_sync or explain behavior for repeated creation attempts, so it stops short of full when/when-not coverage.

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