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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description usefully adds that this is a cross-domain aggregate (builds, GHA jobs, storage, sandboxes) and gives the backing RPC path (UsageService/GetUsage), but says nothing about auth/permission scope, data latency, or rate limits.

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 that leads with the verb and resource before the enumeration of outputs. The category list is long but each item carries information about what the response contains; the trailing 'Depot: UsageService/GetUsage' is minor filler.

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 output schema, the description does useful duty by naming the result categories the agent will receive. Read-only status comes from annotations and parameters are fully documented in the schema, so the only real gap is the absence of alternative-routing guidance.

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 100% and both date-time parameters are documented in the schema with RFC 3339 format and examples. The description only echoes this via 'over a window', so it adds no syntax or boundary-rule meaning beyond the schema. Baseline 3 applies.

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 ('Get the organization's Depot usage') plus the scoping dimension ('over a window'), then enumerates exactly what is aggregated: container builds per project, GHA jobs per repo/workflow/runner, storage, and agent sandboxes. That enumeration implicitly separates it from the narrower sibling depot_gha_get_analytics.

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?

Usage is only implied: an agent can infer it is the aggregate usage-reporting call for a time window, and that start_at/end_at must bracket the window. No explicit when-to-use, when-not-to-use, or named alternative (e.g. depot_gha_get_analytics for a GHA-only view) is given.

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