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

With no annotations provided, the description carries the full burden of disclosing effects. The only behavioral hint is 'Browser-based tool,' but it doesn't explain whether the tool modifies the original file, creates a new file, uploads data, or what limitations exist. The lack of detail on side effects makes transparency poor.

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, clear sentence that is front-loaded with the essential action. There is zero wasted text, and it efficiently conveys the core purpose. It earns a perfect score for conciseness.

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?

Despite a simple schema and no output schema, the description is insufficient for an agent to fully understand the tool. It does not explain what the user receives (e.g., a modified PDF for download), how to provide the PDF, or any browser-based workflow steps. Given the lack of annotations and output schema, more context is needed.

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 zero parameters, so the baseline for this dimension is 4. The description doesn't add parameter details (since none exist), but it also doesn't mislead. It implies user interaction through a browser, which is consistent with the empty schema.

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 a specific action ('Add text/annotations') on a specific resource ('PDF'), which clearly distinguishes it from sibling tools like pdf-join, pdf-split, or pdf-compress. The parenthetical 'Browser-based tool' adds context. This is a clear and unambiguous purpose.

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 guidance on when to use this tool vs alternatives. No exclusions, prerequisites, or alternatives are mentioned. The description only states what the tool does, not the recommended use cases or how it differs from other PDF editing tools.

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