set_timer

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

Annotations declare non-read-only, non-destructive, closed-world, so the description's job is to add context — and it does, disclosing the asynchronous side effect (a desktop notification fires on completion). It stops short of saying whether the timer persists across sessions or how a created timer is later identified.

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 short sentences, zero waste, with the core action front-loaded and the side effect immediately after. Nothing could be removed without losing information.

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 low-complexity, 3-optional-parameter tool this is close, but with no output schema the description should say what a successful call yields (e.g., a timer id) since that is plausibly what cancel_timer needs, and should clarify the minutes/seconds interplay. Annotations cover the safety profile, so the remaining gap is about return/identity, not risk.

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 100% and the schema already explains the default label and the minutes-to-seconds conversion, so the baseline is 3. The description adds nothing beyond this and leaves an important semantic open: no parameter is required, so what happens if neither minutes nor seconds is supplied is undefined.

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?

Uses a specific verb and resource ("Set a countdown timer") and adds the observable outcome ("Sends a desktop notification when it fires"). It does not explicitly name the timer siblings (list_timers, cancel_timer, cancel_all_timers) to differentiate, but the name plus description leaves no ambiguity about what it does.

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 is implied by the sibling set: this creates a timer, whereas list_timers/cancel_timer manage existing ones. There is no explicit 'use this when…' guidance and no exclusions (e.g., that this does not replace an existing timer or that cancellation requires another tool).

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