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

Annotations only declare the safety profile (readOnly=false, idempotent=false, destructive=false, openWorld=false). The description adds genuinely useful behavior beyond them: quiet-time suppression ('Calls within its quiet time after a ring are ignored'), the paid-plan requirement, the private/friends-only visibility constraint, and the returned payload (alarm, address to call, link).

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 core purpose, then constraints and return values in a compact block of roughly 100 words for an 18-parameter tool. Sentences are long and list-heavy at points, but almost nothing is wasted.

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 complex mutation tool with 18 params and no output schema, the description covers purpose, prerequisites, key runtime behavior (quiet time), visibility limits and return values. It leaves the many cosmetic parameters (theme, vibe, snooze, wallpaper) to the schema, which is fair at 94% coverage, but a little more on the callable web address would help.

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?

With 94% schema description coverage, the schema already documents the 18 parameters in detail, so the baseline is 3. The description restates a few of them (quiet time, private/friends) but adds no syntax or format meaning beyond what the schema provides.

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 ('Sets an alarm that rings... whenever its private web address is called') with the triggering mechanism spelled out. It differentiates from siblings by naming the parallel alarm types ('a time, a post, a price, a trade or an event link each has its own alarm'), which maps to set_time_alarm, set_post_alarm, set_price_alarm, set_trader_alarm and set_event_alarm.

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 clear selection condition ('For something only another system can see happen') and prerequisites (paid plan; private or friends, never public). Alternatives are implied by pointing at the other alarm types, but it never says explicitly to use set_time_alarm etc. instead, so it stops short of full routing guidance.

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