merge_pdfs

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

With no annotations, the description fully discloses behavioral traits: preserves bookmarks/links/formatting, returns a temporary URL (valid ~1 hour), cost, payment method (Bitcoin Lightning), and that no API key is needed. It does not mention error handling but is otherwise thorough.

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 moderately concise, containing multiple sentences but each adds value. It front-loads the core purpose and then adds details. Could be slightly shorter but no redundancy.

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 lack of output schema, the description explains the return format (JSON with url). It covers constraints, payment, ordering, and provides an alternative tool. The information is sufficient for an agent to correctly invoke the 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?

The input schema already provides 100% coverage for the two parameters. The description adds context: paymentId must be a valid paid payment (implied from create_payment), and files are base64-encoded PDFs. This goes beyond the schema's descriptions, justifying a score above the baseline.

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 merges PDF files into a single document, preserving bookmarks, links, and formatting. It explicitly distinguishes itself from the sibling tool 'convert_file' by specifying the alternative for format conversion.

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 explicit usage guidelines: minimum 2 files, no maximum, files concatenated in array order, and a clear alternative (convert_file) for format conversion. It also explains the payment requirement and the process with create_payment.

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