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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral detail beyond annotations: without part it returns 편/품 list, with part it returns 절 list including ids. It stops short of describing exact output shape or error handling, but this is sufficient for a read-only outline tool.

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 description is three short sentences with no filler. It front-loads the resource, then efficiently gives conditional behavior and the intended use case. 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?

For a simple two-parameter read-only tool with no output schema, the description covers the two invocation modes, the optional parameter, and the use case. A minor gap is that the no-part list is not explicitly said to include ids, but the overall purpose is clear enough for an agent to invoke the tool correctly.

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%, so the baseline is 3; the schema already documents book IDs and part partial matching. The description adds the conditional semantics of the optional part parameter and notes the returned data includes ids, which helps the agent decide whether to pass part. This goes slightly beyond the schema without repeating it.

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 resource (책의 차례, a book's table of contents) and a clear action: retrieve structural navigation. It distinguishes two invocation modes (with or without part) and contrasts itself with lookup/search tools via the phrase '특정 자리를 알고 찾아갈 때 .'.

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 description explicitly says the tool is for navigating to a specific known location ('특정 자리를 알고 찾아갈 때 다'), which implies it should be used when the agent already knows the structural place. It does not explicitly name sibling alternatives or state when not to use it, but the usage context is clear enough.

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