List a book's chapters

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: the DRM and local-download constraints that determine success or failure. It stops short of describing failure behavior for nested/edge-case EPUBs, so not a 5.

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?

The core purpose, the return contents, and the key constraint all appear in the first two lines, followed by a compact Args block. No filler.

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?

No output schema exists, so the description is responsible for the return shape, and it does describe the TOC fields. Combined with the precondition note, an agent has enough to call it correctly, though nothing is said about empty results or chapters-without-TOC cases.

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 coverage is 0% on a single parameter, so the description must carry the burden — and it does, stating the ID is numeric and pointing to list_all_books as the source. It is slightly under-specified on whether the ID is a library ID versus an external identifier.

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 specific verb and resource ('List the table of contents for a book') and immediately enumerates the returned fields (titles, order, nesting depth), which cleanly separates it from the sibling get_chapter_content that fetches chapter bodies.

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?

Gives a clear precondition — only non-DRM EPUBs already downloaded to this Mac — which tells the agent when the tool will fail. It does not name an alternative tool or explicitly route the agent elsewhere, so it falls short of a 5.

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