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

Annotations already cover the safety profile (idempotent, non-destructive, not read-only). The description adds real behavioral value beyond that: the owner-only permission requirement and the semantic that interval_days 0 disables check-ins entirely.

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 compact sentences that front-load the primary action and follow with the permission constraint and the 0-means-off rule. No filler language.

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 3-parameter, non-destructive mutation with full annotation coverage and no output schema, the description supplies the operation modes, the authorization prerequisite, and the disable semantic. Only the absence of sibling routing (vs get_checkin_status) leaves a small gap.

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 already documents each parameter, so baseline is 3. The description goes further by clarifying that the two parameters can be combined ('or both') and restating the enabling/disabling semantics of confirm and interval_days 0 in operational terms.

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 mutation with two clear modes: confirming a flow is still valid (confirm) and configuring check-in cadence (interval_days). This distinguishes it functionally from get_checkin_status, but it never names the read sibling so an agent must infer the read/write split from the name alone.

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?

Clearly explains the three usage cases: confirm only, interval only, or both, giving the agent a concrete selection rule. It also notes the owner-only constraint, but offers no explicit when-not guidance or alternative tool routing.

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