Inspect a PDF

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly states 'Read-only, never modifies the file,' which is critical for safe agent decisions. It also mentions the output scope and encryption detection, giving useful behavioral context beyond a bare instruction.

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?

Two sentences with no fluff. The direct 'call this tool' instruction is front-loaded, followed by a compact list of result categories and a clear safety guarantee. Every sentence earns its place.

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 one-parameter read-only inspection tool, the description is largely complete: it specifies the input, the output content, and the safety behavior. There is no output schema, so a bit more detail about the returned structure could help, but the listed fields are sufficient for correct 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 single parameter 'path' is fully documented in the schema with 100% description coverage, so the baseline of 3 applies. The tool description does not add additional parameter detail, but none is necessary because the schema already explains path resolution and expansion.

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 ('inspect') and a clear resource ('a PDF'), then enumerates the exact information returned: page count, page sizes, paper name, metadata, and encryption status. This distinguishes it from sibling PDF tools like pdf_merge, pdf_split, or pdf_text, which perform different 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?

The opening line, 'Call this tool to inspect a PDF,' explicitly states when to use it. It does not name exclusions or explicitly compare to alternatives such as pdf_count, but the scope is clear enough that an agent can reliably choose it for read-only inspection rather than transformation or text extraction.

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