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

Annotations already indicate this is a mutating (readOnlyHint false) and idempotent operation. The description adds valuable behavioral context: it costs 1 credit per call, returns a temporary download link valid for 15 minutes, instructs the agent to include the link in the reply, and clarifies that the angle is additive to existing rotation. This goes beyond annotations and provides practical operational guidance.

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 three concise sentences. It front-loads the core purpose, then covers cost and output details. There is no redundant wording; every sentence earns its place. The structure is clean and easily scannable.

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 simple PDF rotation tool with three parameters and no output schema, the description covers all essential information: the action, the additive rotation behavior, the credit cost, the temporary link, and the instruction to include the link in the reply. An agent has everything needed to invoke the tool correctly without external reference.

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 fully describes all three parameters (100% coverage), so the baseline is 3. The description adds a crucial semantic that the angle is added to each page's existing rotation, which is not captured in the schema. This enriches understanding of how the 'angle' parameter behaves, justifying a score of 4.

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 verb 'Rotate' and the resource 'pages of a PDF', and further specifies that it rotates all or selected pages by 90/180/270 degrees, with the rotation added to each page's existing rotation. This distinguishes it from other PDF tools like merge or split, leaving no ambiguity about its function.

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 does not explicitly mention when to use this tool versus alternatives, nor does it name any sibling tools or provide exclusion criteria. Usage is implied by the clear purpose, but without explicit guidance on when not to use it or which alternative to prefer, the score is limited to 3.

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