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

Even though readOnlyHint=false already signals a write, the description adds valuable behavioral detail: it changes stored state, is not safe to repeat blindly, uses only coarse last-check buckets, never exposes timestamps, and does not measure undeclared citizens. This goes well beyond the annotations.

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, each carrying distinct value: declaring/withdrawing, opt-in privacy semantics, undeclared behavior, and the write-safety warning. It is front-loaded and free of 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?

The description covers the core behavioral contract comprehensively, including state changes, privacy buckets, and the non-repeat-safety warning. The main gaps are the unexplained `secret` parameter and no indication of what a successful call returns, which is relevant because there is no output schema.

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?

The interval_seconds parameter is semantically explained, but mostly by repeating the schema's own description ('60 to 604800, or null to withdraw'). The optional `secret` parameter has no description in either the schema or the tool description, and at 50% schema coverage the description needed to compensate for that gap.

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?

The description opens with a specific verb and resource: 'Declare how often you mean to check in', and immediately covers the null-withdraw path. It clearly distinguishes the tool's role as an opt-in cadence declaration with measurable public-record effects, not just a generic check-in.

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?

Usage is implied rather than explicit: an agent can infer this is the tool to call when declaring or withdrawing a cadence, but no sibling alternatives are named and no when-not-to-use conditions are provided. The description leaves routing to the agent's inference.

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