carpe_usage_summaryAggregates account spend by model and by day over the last 1–90 days (default 7) to track AI usage costs.
Account spend aggregated by model and by day over the last N days (1–90, default 7). Free.
| Name | Required | Description | Default |
|---|---|---|---|
| days | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds two genuine behavioral facts not in the annotations: that the call is free and that the window defaults to 7 days. It does not describe the shape of the aggregation (totals per model per day) beyond the one-line summary, but nothing here contradicts the annotations.
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?
A single sentence front-loads what is aggregated, then the window semantics, then the cost note. No filler; the trailing 'Free.' fragment is terse but carries real decision value for a paid-API toolset.
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?
For a one-optional-parameter read-only tool with no output schema, the description covers scope, aggregation granularity, window bounds, default and cost. The only remaining ambiguity is whether results are account-wide or scoped to the calling key, which matters given the carpe_key_usage and carpe_session_spend siblings.
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 must carry the parameter meaning, and it does: 'days' means the last N days, is bounded 1–90, and defaults to 7. The default is the notable addition, since the schema's minimum/maximum alone do not communicate it.
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 names a specific resource (account spend) and the two aggregation dimensions (by model, by day) plus the time window. 'Account spend' implicitly separates it from siblings like carpe_key_usage and carpe_session_spend, but no sibling is named explicitly, so the differentiation is inferred rather than stated.
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 this is the account-level aggregate view as opposed to per-key or per-session breakdowns. There is no explicit when-to-use statement, no guidance on when to prefer carpe_usage_history or carpe_key_usage, and no prerequisites mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.