Unified cross-account event list

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so safety and idempotency are covered. The description adds the union scope and start-time ordering, but says nothing about result volume, pagination, or what 'readable' excludes – gaps that matter for a cross-account aggregation.

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, front-loaded with the scope, followed by the routing guidance. Every clause carries information and nothing is padded.

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 read-only list tool with no output schema, the description covers scope, ordering, and when to reach for it, which is enough for correct invocation. Minor unaddressed points like pagination or the size of a cross-account result set keep it from being fully complete.

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 description coverage is 100%, so time_min, time_max, and timezone are all documented in the schema. The description only echoes the existence of a time range and adds no format, default, or timezone behavior beyond what the schema supplies, so the baseline of 3 applies.

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 gives a specific verb and resource (list every event) with an explicit scope that separates it from the single-account siblings: 'across every readable account and calendar in a time range'. The added detail that results are 'sorted by start time' further pins down what the tool returns.

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?

It states a clear trigger ('when the user asks about their whole schedule') and a second intended use ('before reasoning about cross-account conflicts'), which points toward find_cross_account_conflicts. It stops short of naming alternatives or stating when NOT to use it (e.g., for a single account, prefer list_events).

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