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

Annotations are empty, so the description carries the full behavioral burden. 'Complete historical' usefully signals this returns a persisted report rather than a live state (contrast vara_get_veil_state), but nothing is said about unknown/prefixed-ambiguous scan_id behavior, auth requirements, or what include_signals does to the payload.

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?

One front-loaded sentence with no filler; the retrieval verb and lookup mechanism lead. Brevity here edges toward under-specification rather than padding, so it does not reach a 5.

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?

With no annotations, no output schema, and 0% schema description coverage, the description should do more. It omits the include_signals flag entirely and gives no failure-mode context for invalid or ambiguous prefixes, which matters for a lookup tool.

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 0%, so the description must compensate, and it partially does: 'short prefix' documents that scan_id accepts a truncated identifier, which the bare 'Scan Id' schema entry does not convey. However, include_signals is never mentioned, leaving one of two parameters entirely undocumented.

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 (Retrieve), resource (VaraScanReport), and lookup key (scan_id or short prefix). It is distinguishable from vara_list_scans (enumeration) and vara_run_scan (execution), though it does not explicitly name those siblings.

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?

No when-to-use guidance, no prerequisites, and no alternatives named. An agent must infer that this is the by-id fetch versus vara_list_scans or vara_query_signals from the name alone.

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