backup_object_storage_usage

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

With readOnlyHint already supplied, the description goes well beyond annotations: it discloses the VBR 12.3+ requirement, that shared files are excluded from storedBytes, that caveats flag upper bounds on block-clone repositories, and that found=false returns candidates rather than guessing. This is unusually rich behavioral context for a read tool.

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?

Front-loads purpose, then semantics, then caveats, then an Args block, so it is well structured. It is on the long side, but nearly every sentence carries distinct information about accounting behavior, so little is wasted.

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, so the description must describe the return shape, and it does: repository, restore-point count, full vs incremental bytes, GFS files, job retention, change rate, sharedStoredBytes, caveats, and found. An agent has everything needed to interpret the result and avoid misuse.

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%, so the description carries the full burden and does: it explains that name is matched case-insensitively but exactly as Veeam shows it, and that target is a Veeam target name from config which defaults when omitted. Both parameters are fully clarified beyond the bare schema.

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 and resource: reads the backup storage one VM/agent consumes, per backup, as showback input. It is clearly distinguishable from siblings like backup_storage_ranking and backup_object_list, and the [READ] prefix signals the operation class immediately.

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?

Frames the use case explicitly ('Read before charging', showback input) and gives the operational condition that storage must not be double-counted. It does not name sibling alternatives or state when not to use it, so it stops short of an explicit routing rule.

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