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

With no annotations, the description carries the full burden, but the word "list" adequately implies a read-only enumerator, and "all available" discloses that results are unfiltered and complete. It does not state whether results are paginated, ordered, or whether the returned names come with identifiers needed for follow-up calls — gaps that matter for an unfiltered catalog listing.

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 well-formed sentence with the resource and the scope front-loaded and no wasted wording. Slightly more could be said about the entry-point role, but nothing is redundant.

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 one-optional-parameter read-only tool with no output schema, the description covers what is listed and that naming is localized. It omits how results are shaped — notably whether each book carries an identifier that the sibling tools (list-chapters, get-chapter) expect — which is the main thing an agent needs before chaining calls.

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% and the single locale parameter is already documented with examples ("en", "ar", "fr"). The description's phrase "with localized names" reinforces the parameter's effect on output but adds no syntax or defaults beyond the schema, so the baseline 3 applies.

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 and resource ("List all available books and collections") and enumerates the content categories (Quran, hadith collections, tafsirs), which distinguishes it from siblings like get-verse or search-content that act on content rather than catalog metadata. It stops short of naming a sibling, so a 4 rather than a 5.

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?

There is no explicit when-to-use or when-not-to-use guidance and no mention of alternatives such as search-content for users who already know what they want. The only usage signal is implicit in "all available," which suggests a discovery/entry-point role, but the agent must infer that.

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