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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's added value is its disclosure of return content: each plan's id, length and purpose. That is useful behavioral context beyond the structured fields, though it says nothing about ordering, pagination, or the calendar-only nature of the M'Cheyne plan for consumers.

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?

A single front-loaded sentence stating the verb, the resource, and the concrete contents of the result. Every clause earns its place and nothing is repeated from the title or annotations.

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?

With no output schema, the description usefully compensates by naming the fields returned (id, length, purpose) and the plan inventory, which is enough to call a zero-parameter read tool correctly. Only the absence of ordering/response-shape detail keeps it from being fully complete.

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 tool takes zero parameters, so there is nothing to document and the baseline of 4 applies. The description correctly implies an unfiltered full-list operation with no inputs.

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 states a specific verb ('Lists') and resource ('the Cross + Covenant Bible reading plans'), and even enumerates the plan inventory (M'Cheyne one-year plus five topical plans). It is clearly distinct from sibling get_reading_plan_day, though it never names that sibling or any alternative to route between them.

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 only implied: an agent can infer this is the discovery step before calling get_reading_plan_day, but the description gives no explicit when-to-use statement, prerequisites, or named alternative. Nothing is misleading, but nothing is spelled out either.

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