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

Annotations indicate readOnlyHint=false and destructiveHint=false, so the agent knows it mutates or creates output. The description adds no behavioral detail beyond the schema-enumerated modes; it does not state that multiple output files are produced, that the original is unchanged, or any side effects. With annotations present, the description should add context like output naming or file creation, but it does not.

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 a single sentence that front-loads the core action and lists the modes efficiently. It is concise, to the point, and contains no filler. The category tag adds minor metadata without clutter.

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 tool with five parameters and no output schema, the description is thin. It omits the expected result (multiple PDF files), how output is named, and any constraints (e.g., page range syntax). The schema covers parameters but not the overall workflow or return value. An agent would still need to infer what happens after calling this tool.

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 100%, so the baseline is 3. The description adds no additional parameter meaning; the modes it lists are already fully explained in the schema's enum description. It does not clarify the 'pages' format (though the schema has an example) or the 'chunkSize' semantics beyond what schema provides.

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 clearly states the verb 'Split' and the resource 'PDF', and enumerates the four distinct splitting modes (range, all, chunks, even/odd). This makes the tool's function unambiguous. However, it does not explicitly differentiate from closely related siblings like pdf_extract_pages or pdf_delete_pages, which also manipulate pages.

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 provides no guidance on when to use this tool versus alternatives. It merely states the operation and modes. An agent cannot infer prerequisites, like whether the input file must be uploaded first, or when to prefer pdf_merge or pdf_extract_pages instead. No exclusions or context are given.

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