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

Beyond the annotations, the description discloses the credit cost, the one-PDF-per-range output behavior, and the temporary download link with a 15-minute validity. It also instructs the agent to always include the link in the reply, which is actionable and beyond what annotations provide.

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 front-loaded with the core purpose, then provides examples, cost, and output-link behavior. There is minor redundancy between 'One credit regardless of how many files come out' and 'Costs 1 credit per call,' but it is not distracting.

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 adequately covers the return value: a temporary download link, its validity period, and the requirement to include it in the reply. Combined with parameter examples and cost disclosure, an agent has enough information 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?

The schema already covers both parameters, and the description adds meaningful semantics for 'ranges': 1-indexed pages, comma-separated groups, and concrete examples. This exceeds the baseline for a fully schema-covered tool.

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 ('Split'), a clear resource ('a PDF'), and the scope ('by page ranges'), and clarifies the output granularity with 'Creates one PDF per range.' This distinguishes it from sibling tools such as merge_pdfs and pdf_to_images.

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 gives clear context for when to use the tool: splitting a PDF into page-range-based files, with explicit range syntax examples. It does not explicitly name sibling alternatives or exclusions, but the intended use case is unambiguous.

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