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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, non-open-world), but the description adds genuinely useful context that the annotations cannot: that links resolve in each opener's own timezone and that no server-side timer is created. That resolves the main confusion the 'create_' name would otherwise cause.

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, correctly front-loaded with the core behavior, followed by the timezone nuance and the negative constraint. Every sentence earns its place with no filler.

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?

An output schema exists, so return-format explanation is unnecessary, and the low-complexity, two-parameter surface is nearly fully described. The only gap is the undocumented 'label' parameter, which is minor given the tool's simplicity.

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 0%, so the description must carry the load. It compensates for 'time' with format examples ('9pm or 17:30'), which is real value, but the optional 'label' parameter is never explained in either the schema or the description, leaving half the parameters undocumented.

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 resource (a validated link to the next local clock time) with concrete examples of the accepted value, and implicitly carves out the sibling create_timer with 'does not schedule a server timer.' It never names the alternative explicitly and the verb 'return a validated link' leaves slight ambiguity about whether anything is persisted, so it falls short of the top tier.

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 clear context for when the tool applies (per-opener timezone, clock-time links rather than server timers) and effectively excludes the create_timer use case. No siblings are named and no prerequisites or exclusions beyond the timer contrast are stated.

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