Recover book metadata

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

Annotations declare readOnlyHint and openWorldHint; the description reinforces and adds substance by explaining the external providers (Open Library, Google Books) and the lookup fallback chain (identifiers/ISBN first, then title/author). 'Preview only ... never writes' is valuable confirmation of the safety profile. It omits network failure/rate-limit behavior and what an empty match set looks like, keeping it below 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?

Two dense sentences, front-loaded with the trigger condition, then mechanism, then the critical preview-only constraint. No filler and nothing repeated from the title.

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?

An output schema exists, so return shape needn't be spelled out, and the description still flags that the result is a changes object for calibre_update_book. Combined with the provider list and fallback chain, an agent has enough to call it correctly; only edge-case behavior (no match, provider outage, library scoping) is absent.

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 0% for all four parameters, so the description carries the full burden. It loosely covers the provider selection (Open Library / Google Books maps to `sources`) and the identifier-vs-title/author inputs, but never explains the `id` vs `bookId` distinction or what `library` scopes, leaving half the parameters ambiguous.

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 (propose) plus resource (real metadata) and the precise triggering condition (a book with a missing/raw-filename title). It also names the mechanism (online provider lookup) and the downstream consumer (calibre_update_book), so an agent knows exactly what this tool does and that no sibling duplicates it.

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?

The when-to-use is explicit: a book whose title is missing or is a raw filename. It also makes the use-vs-alternative relationship clear by noting this is preview-only and that the returned changes object feeds calibre_update_book rather than being applied here. It stops short of stating when NOT to bother (e.g. title already correct) or what to do on zero matches.

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