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

With all annotations false, the description carries the full burden of behavioral disclosure. It goes beyond annotations by detailing safety mechanisms (traversal/absolute-path/symlink refusal, zip bomb size and ratio caps, dry_run behavior) and the unusual output format (per-entry download links valid for one hour). It does not explicitly state whether it writes to disk, but the 'no directories' and download-link phrasing strongly imply a non-persistent extraction. This is substantial added context beyond the minimal annotation signals.

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 zero filler. The core action is front-loaded, followed by the most critical behavioral notes (safety and output format). Every clause earns its place, and the structure makes the essential facts immediately visible.

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 an 8-parameter tool with no output schema and empty annotations, the description covers the key behaviors: extraction scope, safety guards, dry_run semantics, and the return format (download links). It does not enumerate default values (though those are in the schema) or error conditions, but for an agent deciding whether to call it, the essential information is present. The lack of an output schema is mitigated by the explicit statement about download links.

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?

Schema coverage is 100% with descriptive parameter comments for all 8 parameters, so the baseline is 3. The description reinforces safety parameters (max_ratio, max_total_mb) and dry_run, but does not add format or syntax details beyond what the schema already provides. It does mention the out_dir is ignored (via 'no directories'), but that is already in the schema description. Overall, the description does not significantly augment parameter understanding.

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 opens with a clear verb+resource ('unpack an archive') and immediately distinguishes itself from sibling tools like zip_extract_text by noting every entry comes back as a download link, which is a unique behavior. This is specific enough that an agent can tell it apart without opening other tool schemas.

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 states when to call it ('Call this tool to unpack an archive'), providing a clear context. However, it does not mention any alternative tools (e.g., zip_list for listing, zip_extract_text for text-only extraction) or any exclusions, so it lacks the explicit when-not-to-use guidance that would earn a 5.

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