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

With no annotations, the description carries the full burden and does well: it discloses the return shape (verdict, risk_score, findings), the verdict enum values, and the crucial limitation that detection is heuristic rather than signature-based AV. It omits whether the file is stored or transmitted anywhere, which keeps it from a 5.

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 dense sentences: the first front-loads what is scanned, the second delivers the output shape and the key caveat. No filler and nothing redundant with structured fields.

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 tool with no output schema, the description supplies the return fields, the verdict taxonomy, the detection scope, and the heuristic disclaimer. An agent has everything needed to decide to call it and to interpret the result.

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?

Single required parameter with 100% schema description coverage ('PDF file content as base64'), so the schema already does the work and the baseline is 4. The description adds nothing further about the parameter, which is acceptable at this coverage level.

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?

States a specific verb (scan) and resource (PDF) plus an enumerated list of what is detected: JavaScript, embedded files, Launch/Open actions, XFA forms, encryption. This clearly distinguishes it from siblings like pdf_info or pdf_text, which inspect content rather than assess hostility.

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 closing clause 'Static heuristics, NOT an antivirus' sets an explicit scope boundary and warns against over-trusting results. It does not name an alternative tool or state when to prefer another sibling, so it falls short of a 5.

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