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

With no annotations, the description carries the full behavioral burden. It usefully discloses that encrypted PDFs and passwords are sent to the server for decryption and mentions credit/pricing coverage. However, it does not explain password storage, error behavior, output handling, or authentication requirements, and the subsequent 'Runs in the browser' statement sits awkwardly beside the server-side decryption disclosure.

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 purpose is front-loaded and easy to find, but the description includes a long pricing/credit paragraph that is mostly irrelevant to invoking the tool and contains a duplicated period. The core operation could be stated more compactly.

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 zero-parameter tool with no annotations and no output schema, the description gives adequate high-level context about server-side decryption and billing. It still leaves important gaps: how the PDF and password are actually supplied, where the unlocked copy is saved, and what the agent should expect back after invocation.

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 tool has zero parameters, which usually gives a baseline of 4. But the description tells the agent to 'Enter the current PDF password,' even though the schema exposes no password parameter or file parameter. This creates ambiguity about whether the agent must supply an argument or whether password entry happens through a browser UI.

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 a specific verb and resource: unlock a PDF by entering its current password and saving a copy. This distinguishes it from most sibling PDF tools such as merge, split, or compress. It does not explicitly contrast with the PDF editor or open_tool sibling, so it stops short of a 5.

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?

Usage is implied: this is for encrypted PDFs where the current password is known. There is no explicit when-to-use vs. alternatives guidance, and no note about what to do if the password is unknown or the file is not encrypted.

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