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

With no annotations, the description must carry all behavioral disclosure. It states that the tool is browser-based and encrypts PDFs, but does not disclose file handling behavior, password input mechanism, or potential side effects.

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, direct sentence with minimal redundancy. The parenthetical '(Browser-based tool)' adds useful context without bloat.

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?

While the tool is simple, the description omits usage context such as how password input is handled or how it contrasts with pdf-unlock. Given the simplicity and no output schema, it is minimally acceptable but not rich.

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 contains zero parameters, so the description faces no parameter documentation burden. The baseline for zero-parameter tools is 4, and the description adequately conveys the lack of parameters without adding unnecessary detail.

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 uses a specific verb ('Encrypt') and resource ('PDFs'), making the tool's purpose clear. However, it does not explicitly differentiate from sibling tools like pdf-unlock, which perform related operations.

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?

No guidance is provided about when to use this tool versus alternatives such as pdf-compress or pdf-sign. The description only states the action, leaving the agent to infer context.

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