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

Annotations already declare readOnly/idempotent/non-destructive behavior, so the safety burden is low. The description adds 'Free (0 credits)' and discloses data provenance ('read from the book's own front matter'), providing useful behavioral context beyond the annotations.

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 with zero filler: the content summary is front-loaded, slug provenance follows, and the 'Free (0 credits)' caveat is isolated at the end. Every sentence earns its place.

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 one parameter and no output schema, the description must carry the return-value burden, and it does: it enumerates authors, description, topics, download links, licence and attribution. Nothing an agent needs to invoke or interpret the result is missing.

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 100% with a detailed slug description that even accepts a cali.org/books/... URL. The tool description reinforces this by naming the source tools and giving a second example, adding value beyond the schema alone.

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 precisely what it does: returns one CALI eLangdell title in full with authors, description, topics, PDF/EPUB/Word links, licence and attribution. The 'one ... title in full' phrasing clearly distinguishes it from sibling tools elangdell_titles and elangdell_search.

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?

Explicitly routes usage: 'Takes the slug from elangdell_titles or elangdell_search', which tells an agent when to call this tool (after a slug is already known) and what inputs are valid. It does not spell out exclusions, but the sibling workflow is clear.

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