spend

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

No annotations provided, so description carries full burden. Successfully discloses return structure (total spend, execution count, cost averages) and aggregation dimensions (capability, provider) compensating for missing output schema. Implies read-only operation through 'Get'/'Shows' verbs. Could add auth needs or rate limit notes.

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?

Three sentences with zero waste: action statement first, return value disclosure second (compensating for no output schema), default behavior third. Every sentence earns its place with no redundancy.

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?

Given single optional parameter, 100% schema coverage, and no output schema, the description adequately explains the conceptual data returned (metrics and grouping). Missing only minor details like pagination behavior or timezone handling for the period.

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 100% with the 'period' parameter fully documented. Description repeats the default behavior ('Defaults to current month') but adds no additional semantic context about the date format or validation beyond what the schema provides. Baseline 3 appropriate.

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 specific verb 'Get' + resource 'spend breakdown' and scope dimensions 'by capability and provider'. The scope specification helps distinguish from siblings like 'budget' (limits), 'check_balance' (current credit), and 'get_ledger' (transaction log), though it does not explicitly name alternatives.

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?

Provides implied usage through 'Defaults to current month', signaling when users might need to specify the 'period' parameter. However, lacks explicit guidance on when to use versus siblings like 'budget' or 'check_balance', or when to prefer over 'get_ledger'.

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