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

With no annotations, the description carries the full behavioral burden, yet it discloses nothing about matching behavior (exact vs keyword), result shape, pagination via limit, or failure modes. Only the "PRO" label hints that a subscription is involved, and that is already in the schema.

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?

It is front-loaded and free of padding, but the brevity comes from omission rather than efficiency. Two fragments are not enough to carry these gaps.

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?

Three parameters, no annotations, no output schema, and two siblings competing for the same task space. The definition does not supply enough to reliably differentiate or invoke the tool beyond a minimal keyword guess.

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 only 33%: access_token is documented, but creator and limit are not. The word "keyword" implies partial/fuzzy matching on creator, which is genuinely useful, but limit's semantics and creator's exact matching rules remain undocumented in both places.

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 ("Search NDL") plus the searchable field (creator/author), which is concrete. However, "PRO" is the only signal separating it from siblings like library_search_pro, and it never explains what the premium variant does differently.

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 guidance on when to use this tool versus library_search or library_search_pro, nor any stated prerequisites beyond the vague "PRO" prefix. The agent must infer routing from the tool name alone.

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