pdf_merge

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

The warning about form fields being flattened (visual appearance preserved but interactivity lost) adds crucial behavioral context beyond the annotations. This side effect is not inferable from the idempotentHint or destructiveHint annotations.

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 total: the first establishes purpose immediately, the second delivers a critical behavioral warning. Zero redundancy or filler content.

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 straightforward file manipulation tool with complete input schema coverage and clear annotations, the description is sufficient. The form field warning addresses the primary 'gotcha' of PDF merging operations.

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?

With 100% schema description coverage, the structured schema already clearly documents both filePaths (with ordering note) and outputPath. The description doesn't add parameter-specific semantics but doesn't need to given the comprehensive 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?

The description clearly states the specific action ('Merge') and resource ('PDF files'), distinguishing it from sibling tools like pdf_split, pdf_extract_text, or pdf_encrypt.

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?

While it doesn't explicitly name alternatives, the warning about form fields becoming non-interactive provides implicit guidance about when not to use this tool (i.e., when interactive form preservation is required).

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