trmnl_list_room_booking_calendar_screens

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely non-obvious behavior: an empty list means the calendar is on no device, a null screen means not-yet-rendered rather than not-showing, and image_url is a presigned link expiring in ~5 minutes that must be fetched promptly. That expiry constraint is actionable operational context nothing else conveys.

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 the return semantics, then the null/empty distinctions, then the URL caveat — good ordering with little waste. The trailing endpoint line is redundant for tool selection but cheap and useful for API mapping.

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?

No output schema exists, and the description compensates well by describing the shape of each entry (device plus image) and the two ambiguous null/empty cases. What is missing is routing guidance relative to the calendar-binding and collection-screen siblings, which is minor for a read-only listing tool.

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 50% overall, but the leaf fields (calendar id, installation id, profile default) are all documented in the schema, and the description adds no parameter-level detail whatsoever — no explanation of how installation_id scopes the lookup or what profile selects. Baseline 3 for a schema that does the heavy lifting.

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 ('Read the screens a calendar is showing on') and immediately clarifies the granularity: one entry per device, with the image that device is rendering. That makes it distinguishable from trmnl_list_room_booking_collection_screens and the calendar CRUD siblings without needing their 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?

The usage context is implied (inspect which devices display a given calendar) and the empty-list / null-screen cases are explained, but there is no explicit when-to-use statement and no named alternative such as trmnl_list_room_booking_collection_screens or trmnl_bind_room_booking_calendar_device. An agent can infer the case but must do the routing itself.

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