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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description still adds value by disclosing the chapter 0/1 equivalence, the truncation behavior, and the exact return fields including truncated and markdown_url. It stops short of describing pagination or rate-limit behavior, keeping it a solid 4 rather than 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?

Front-loaded with the purpose, then cleanly segmented into when-to-use, do-not-use, and returns. Every clause earns its place; 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?

With no output schema, the description usefully enumerates the return fields and covers the key edge case and the primary alternative. It is nearly complete, with the only gap being undocumented lang/slug parameter semantics.

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 50%; chapter and max_chars are documented, but lang and slug are not. The description adds real meaning for chapter ('0/1 are both accepted for the opening chapter') and implies truncation semantics for max_chars, but says nothing about lang or slug, so it only partially compensates for the coverage gap.

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 ('Clean Markdown of a single chapter') and positions itself ('the recommended way to put Cyber Library text into an agent context'). It names the sibling it complements (cyberlibrary_get_toc) and the one it is not (cyberlibrary_get_markdown), so an agent can route without opening schemas.

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?

Explicit 'When to use: after cyberlibrary_get_toc, to read the specific chapter you care about' and 'Do not use: to read an entire book in one shot (use cyberlibrary_get_markdown, but mind the size)'. This names the alternative and the condition that selects it plainly.

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