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

The description states the operation and return value (file_id + URL), implying a new PDF is created, but it does not explicitly mention whether the original is preserved or if any side effects occur. However, the annotations (readOnlyHint=false, destructiveHint=false) align with a non-destructive write, so no contradiction exists.

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, concise sentence that conveys the essential information without redundancy. It is well-structured and easy to parse.

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?

The description fully explains the tool's function and return value, which is sufficient for an agent to call it correctly. It does not provide an output schema, but for a simple metadata setter, the return format is adequately described.

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 description mentions all parameters (title, author, subject, keywords, creator) and specifically clarifies that keywords can be an array or comma string, matching the schema. The only param with a schema description (pdf) is also well-defined. This compensates for low schema coverage.

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 action (set), the target resource (PDF), and the specific fields (title, author, subject, keywords, creator). It also clarifies the behavior that only provided fields are changed, leaving no ambiguity about the tool's 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?

The description gives a direct usage hint by specifying that only supplied fields change, guiding the agent on partial updates. It does not mention alternative tools or contextual triggers, but the action is straightforward enough that an agent can infer when to use it.

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