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

Annotations already declare readOnly/idempotent/non-destructive/non-open-world, so the safety profile is covered. The description goes beyond them by disclosing the per-row return shape (id, name, workDays encoding 0=Sun..6=Sat, hoursPerDay, isDefault, exceptionCount), which matters because no output schema exists. Pagination/iteration behavior is left unstated.

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?

Three short sentences, zero filler, and the core purpose plus the sibling routing are 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?

With no output schema, the return-field enumeration is exactly what the description should supply, and the sibling pointer covers the main adjacent use case. The remaining gap is pagination guidance for the undocumented cursor.

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 only 50%: limit is documented (default 50, max 50) but cursor has no description. The description says nothing about limit, cursor, or how to page through results, so it does not compensate for the gap.

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?

Specific verb+resource+scope ('List working calendars in this org') and it explicitly names the sibling get_working_calendar as the tool for a different need. An agent can distinguish the two without opening schemas.

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?

'PREFER get_working_calendar for the full exception list' gives an explicit alternative plus the condition that selects it. It stops short of stating the reverse case (use this list for org-wide overviews) or any prerequisites, so it is clear context rather than complete routing.

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