Get Cost Breakdown

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

With no annotations, the description carries the full burden of behavioral disclosure. It does not state that the operation is read-only, describe the output structure, or mention any rate limits or data scope (e.g., multi-account aggregation). The description adds no behavioral context beyond the basic intent.

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 a single, efficient sentence with no fluff. It front-loads the core purpose, though the brevity sacrifices useful details like parameter dependencies. It is appropriately concise but not optimally informative.

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?

The tool has 3 optional parameters and an output schema, yet the description does not explain the default behavior (days=30), the dependency between tag_key and group_by, or the full set of grouping options. It is insufficient for an agent to call it correctly without deep schema inspection, especially given the absence of behavioral hints.

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?

The schema already documents all parameters (100% coverage). The description adds meaning by clarifying the grouping options SERVICE and TAG, but omits USAGE_TYPE and fails to note that tag_key is required when grouping by TAG. This partial addition gives a baseline of 3, as it provides some value but is incomplete.

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 retrieves a cost breakdown, with a specific verb and resource. It mentions grouping by service or tag, which distinguishes it from project_costs but does not explicitly name alternatives or cover the USAGE_TYPE grouping option.

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?

No guidance is provided on when to use this tool versus siblings such as project_costs or get_rightsizing_recommendations. There is no mention of prerequisites, context, or exclusions, leaving the agent to guess applicability.

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