merge_pdfs

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

With no annotations, the description carries the full burden. It usefully discloses the ordering guarantee and that passwords apply to encrypted inputs, but it omits the critical mutation semantics: what happens when output_path already exists (the overwrite parameter is never mentioned), and whether inputs are modified.

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 short sentences, front-loaded with the core action and output target, followed by the less common password case. Nothing is padded, though the second sentence could be folded in for tighter structure.

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 4-parameter file-mutating tool with no annotations and no output schema, the description covers the primary flow and the encrypted-input case but leaves the overwrite behavior and the failure/return expectations unstated. A reader can call it, but not confidently predict side effects.

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 0%, so the description must compensate, and it does explain input ordering, output_path, and the passwords map ('maps an input path to its password') beyond the bare schema. However, the overwrite parameter is left completely undocumented in both schema and description.

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?

States a specific verb and resource ('Merge PDFs') plus the destination ('into output_path') and a meaningful behavioral detail (order is preserved). The action is unambiguous and clearly distinct from siblings like split_pdf or extract_pages, though it never names or contrasts those siblings explicitly.

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?

There is no when-to-use guidance and no routing to or away from alternatives such as images_to_pdf or convert_to_pdf. The only situational hint is the implicit note that passwords are needed for encrypted inputs, which is a parameter detail rather than usage guidance.

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