document_signer

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

Annotations indicate destructiveHint=true, so the tool modifies files. The description confirms it writes signed output back locally, which aligns. It adds significant behavioral detail: signature types, appearance customization, positioning options, and reading/writing behavior. This goes beyond the basic annotation hints to inform the agent about the tool's capabilities and behavior.

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 well-structured with clear sections, bullet points, and no redundant information. Every sentence provides useful context. It is appropriately sized for the complexity of the tool, front-loading the main purpose and then detailing options efficiently.

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 complexity (5 parameters, nested objects, no output schema), the description covers the main aspects: input/output paths, signature types, appearance, positioning. It does not explain the return value or error handling, but since the tool writes a file, the agent can infer output is the signed PDF. The description could mention that the output is a new signed file and whether it overwrites existing files, but it still provides substantial contextual completeness.

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 has 100% description coverage, so each parameter is well-documented in the schema. The tool description adds value by grouping options into categories (signature types, appearance, positioning) and summarizing at a high level, but it does not add significant detail beyond what the schema already provides. Thus a baseline score of 3 is appropriate.

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: 'Digitally sign PDF files using the Nutrient Sign API.' It specifies the type of files (PDF), the API used, and the input/output locations (local file system or sandbox). The sibling tools are different (e.g., ai_redactor for redaction, document_processor for general processing), so this tool is well-distinguished.

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 explains what the tool does and lists signature types and options, but it does not provide explicit guidance on when to use this tool versus alternatives. For example, it does not mention when to prefer CMS over CAdES or when to use this instead of document_processor. The context of use is implied by the detailed options, but no direct comparison with siblings is given.

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