backup_object_storage_usage

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

With no annotations, the description carries the full behavioral burden and does so well: it explains sharedStoredBytes vs storedBytes semantics (shared files never counted in storedBytes), flags that storedBytes may be an upper bound for block-clone repositories and shared-file-unaware servers, notes compatibility (VBR 12.3+), and states that found=false returns name candidates rather than guessing.

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?

It is dense but front-loaded, leading with the one-line purpose before the behavioral caveats and args. Every clause carries real information (units, caveats, version requirement), though the long prose run is close to overload and could be broken up further.

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?

There is no output schema or annotation coverage, yet the description enumerates the return content (repository, restore-point count, full vs incremental bytes, GFS files, job retention, increment-vs-full change rate, caveats) and the found=false behavior. Nothing an agent needs to invoke it correctly appears missing.

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 description coverage is 0% with two parameters, so the description must compensate — and it does. It documents 'name' as Veeam's displayed object name, case-insensitive and exact-match, and 'target' as a Veeam target name from config with a default when omitted, adding matching semantics the bare schema lacks.

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 states a precise verb+resource: it reports the backup storage a single protected object consumes, itemized per backup, as showback input. It is clearly distinguishable from siblings like backup_storage_ranking (cross-object ranking), backup_object_list (enumeration) and repository_state (repository-level health), so an agent can route without opening a schema.

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?

It gives clear usage context — 'Read before charging' and 'No pricing — apply your own rates to the bytes' — which frames the showback/chargeback use case and the tool's boundary. It stops short of naming an explicit alternative or a when-not-to-use condition versus backup_storage_ranking, so it is strong but not fully explicit routing guidance.

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