merge_pdfs

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

With no annotations, the description carries full burden. It discloses that the tool merges PDFs, returns base64, and uses order provided. However, it omits details like whether original files are modified, error handling, or file size limits. Transparency is adequate but not rich.

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?

Two sentences, no extra words. The first sentence states the core purpose and return format; the second adds a key behavioral detail. Perfectly front-loaded and efficient.

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?

Given the tool's simplicity (one parameter, no output schema), the description is fairly complete. It covers the main behavior, output format, and ordering. Missing elements like error handling or file existence checks are minor, and the context is sufficient for effective use.

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% with a description for file_paths. The tool description adds 'Files are merged in the order provided,' which clarifies ordering semantics beyond the schema. This adds meaningful value, earning a score above baseline 3.

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 tool's function: merging multiple PDF files into a single PDF. It specifies the output format (base64-encoded) and that order is preserved. This distinguishes it well from siblings like extract_pages or split_pdf.

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 implies usage (for combining PDFs) but provides no explicit guidance on when to use versus alternatives or when not to use. It mentions order preservation, which is helpful, but lacks exclusions or comparisons to siblings.

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