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

Annotations already communicate idempotency and non-read-only behavior. The description adds the ordering behavior, which is useful, but it does not disclose potential side effects such as whether the original PDFs are modified or whether a new file is created.

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 a single, focused sentence that avoids filler. The key ordering constraint is included immediately, making it easy to parse.

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 single-purpose tool, the description plus rich input schema and output schema covers the essential invocation details. It does not provide explicit routing to alternatives, but that gap is already reflected in the usage_guidelines score.

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 description coverage is 100%, so the parameters are already well documented. The description adds no parameter-level detail beyond what the schema provides, matching the baseline for fully-covered schemas.

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 the exact verb ('merge'), the resource ('PDFs'), and a meaningful constraint ('in the supplied order'). This clearly distinguishes it from siblings like split_pdf, add_pdf_watermark, and conversion tools.

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 when to use the tool: when multiple PDFs need to be combined in a given order. However, it does not explicitly state when not to use it or name alternative tools, leaving the usage guidance implied rather than explicit.

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