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

Goes well beyond the annotations by disclosing the mechanics: rrule is validated before persistence, per-occurrence rows are expanded by the materialiser, every occurrence actually SENDS via email/Slack/SMS, and a delivered message cannot be recalled. It also clarifies that cancelling only stops occurrences that have not fired, which directly qualifies the destructiveHint.

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?

Four sentences, front-loaded with what it does, then the persistence pipeline, then the irreversible-delivery warning, then the usage gate. No sentence is filler and the most consequential fact (messages cannot be recalled) is placed prominently.

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?

Output schema exists and annotations declare destructive/openWorld/non-idempotent, so the description's job is the judgment layer — and it delivers exactly that: irreversibility, delivery side effects, and the escalation condition for recipients. An agent has everything needed to decide and call correctly.

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 100% and the per-parameter docs are already rich (including the recipients escalation warning and tenant_slug refusal behavior). The description reinforces the recipients constraint but adds no syntax or format meaning the schema does not already carry, so this sits at the baseline.

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?

Opens with a specific verb+resource ("Create a recurring reminder schedule") and scopes it to recurring reminders only, which implicitly separates it from the single-fire kb_reminders_create sibling. It never names that sibling outright, so the differentiation requires a small inference.

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 an explicit gating condition ("Create one only when the user asked for a repeating reminder, addressed to the people the user named"), which covers both when to use it and who it should target. It stops short of naming when-not/an alternative tool explicitly.

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