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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds that only *published* guides are retrievable and that the slug is validated, which is meaningful context beyond the annotations, but it says nothing about error behavior for unpublished or unknown slugs.

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?

One short sentence, front-loaded with the verb and the key scoping word 'published'. There is no filler and nothing to trim.

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?

For a simple single-param read tool whose annotations cover safety, this is close to adequate, but with no output schema and no parameter documentation, the description leaves the return shape and the distinction from search_prayer_guides unstated. It is the minimum viable rather than 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 single slug parameter has 0% schema description coverage, so the description carries the burden, and it only loosely characterizes the value as a 'validated Prayer in Hand slug'. The format constraints (pattern, maxLength) live in the schema, and the description adds no format or sourcing guidance beyond the word 'validated'.

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 (Fetch) and resource (one published guide) and scopes it to a single item, which implicitly contrasts with the sibling search_prayer_guides. It never names the siblings, so the differentiation is inferred rather than explicit.

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: call this when you already have a slug for a published guide. There is no statement of when not to use it, no prerequisites, and no pointer to search_prayer_guides as the way to obtain a slug, so the guidance is minimal.

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