hub_usage

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

No annotations are provided, so the description must disclose behavior. It explains the conceptual split between SUPPLIED (client-reported) and MEASURED (hub-derived) data and warns against mixing them. This provides meaningful behavioral context beyond just saying 'returns usage'. However, it does not specify return format or whether agent/project filter the results, so it is not fully transparent.

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?

The description is two sentences and front-loads the purpose. The second sentence adds important nuance about the supplied/measured split and the warning. No unnecessary words.

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 and no annotations, the description should cover return structure and default behavior. It explains the core concept but does not mention the default window of 7 days (though the schema hints at it) or what the response looks like. It also does not clarify behavior when agent/project are omitted.

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 only 33%, with only 'days' having a description. The description adds meaning by mapping 'days' to the window and suggesting 'agent' and 'project' are grouping dimensions. It does not explicitly clarify whether agent/project are optional filters or always part of the grouping, leaving some ambiguity.

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 clearly states the tool reports work cost over a time window, aggregated per project and per agent. It distinguishes from hub_usage_add by explaining that SUPPLIED data comes from clients via that tool. This gives a specific verb+resource and differentiates from the sibling.

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 implies this is the read counterpart to hub_usage_add by noting that clients report supplied data through that tool. It does not explicitly state when to use this tool vs alternatives, but the contrast between SUPPLIED and MEASURED gives context. There is no explicit exclusion or when-not-to-use, so not a 5.

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