Split a PDF

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

Annotations only declare the generic write profile (readOnly=false, destructive=false, idempotent=false); the description adds real substance beyond that: the input file is left unchanged, existing files are never overwritten, and there is a hard output cap of ~1,000 files. The cap sentence ("at most 1,000 (or one per page for longer PDFs)") is phrased ambiguously, and it does not say whether a name collision errors or skips.

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?

Three dense sentences, front-loaded with the core action and output naming, with no filler. The middle sentence's 1,000-file limit clause is the one place where compression costs clarity.

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 an output schema present and annotations covering the safety profile, the description supplies what an agent still needs: output file naming, the per-range-to-file mapping, a non-overwrite guarantee, and a scale limit. Nothing essential for correct invocation is missing.

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 a 3 is the baseline, but the description earns a point by explaining how the ranges value maps to concrete outputs (-part1, -part2 ordering) and by demonstrating the 'end' keyword. It still adds nothing about output_folder behavior beyond the schema.

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 (splits a PDF) and pins down the output shape precisely: one new file per comma-separated range, named -part1, -part2. That output convention is what separates it from extract_pages or duplicate_pages, though no sibling is named explicitly.

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 worked example ("1-2, 3-end" gives two files) implies when to reach for this tool, but there is no explicit when-to-use, when-not, or pointer to extract_pages for single-range extraction. Usage is inferred rather than stated.

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