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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real context beyond them: the default resolution to today in Mountain Time, the date-only-applies-to-M'Cheyne constraint, and the up-to-150-verses cap on returned text. No contradictions; it simply does not describe error cases.

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 front-loaded sentences with no filler; the primary behavior comes first and the parameter qualifiers follow. Dense but every clause carries meaning.

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 carries the return-value burden and does so reasonably: it names the returned passages, the optional verse text, the translations, and the verse cap. Missing only return-shape details like ordering or empty-day handling.

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%, so baseline is 3, but the description adds value beyond the schema by disclosing the fallback default (today, Mountain Time) when neither day nor date is given, and tying include_text to the ~150-verse limit and translation choice.

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 precise verb and resource: 'Returns the passages for one day of a Cross + Covenant reading plan.' The scope (one day's passages, with optional verse text) is clear enough to distinguish from a single-passage or devotional tool, though no sibling is named explicitly to route the agent.

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?

The description implicitly guides parameter choice ('by day number or ... by calendar date' and the today-in-Mountain-Time fallback), but never states when to pick this over get_passage or get_devotional, nor any prerequisites. Usage is implied rather than spelled out.

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