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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the source is public domain, output is "citations only, never another translation", include_text pulls in WEB or KJV passage text, and weekday dates roll forward to the next Sunday.

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?

Three dense sentences, front-loaded with the verb and resource, then the input modes and the optional text behavior. Nothing is wasted, though the single long first sentence packs several constraints together and could be split for readability.

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 states what is returned (readings plus alternatives, optionally passage text) and documents defaults for date, year and include_text. It is close to complete for an agent; the main omission is guidance on which sibling to choose when the user asks more broadly about a season or feast.

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 the baseline is 3. The description does add real meaning for translation (only WEB or KJV, both public domain, citations never from another translation) and clarifies include_text, but date/occasion/year semantics largely restate what the schema already documents.

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?

Specific verb and resource ("Returns the appointed Bible readings") plus explicit scope: Sunday/major feast from the three-year Sunday lectionary of the 1979 Book of Common Prayer. It also names the exact contents returned (first reading, psalm, second reading, gospel, with alternatives), so an agent can distinguish it from siblings like season_for_date or upcoming_feast_days.

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?

It clearly tells the agent how to select a day: give a date, or an occasion like "advent-1" with a year of A/B/C, and notes that a weekday without its own lessons rolls to the next Sunday. However, it never states when to prefer this tool over siblings such as upcoming_feast_days or season_for_date, leaving routing to inference.

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