get_savings_plan_showback

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

With no annotations provided, the description fully carries the burden of behavioral disclosure. It details the output fields (effective_cost, on_demand_equiv, etc.), prerequisites, and the fact that it uses CUR fields not exposed by Cost Explorer. No contradictions.

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 well-structured with a clear introduction, bullet-pointed output fields, and example queries. However, it is relatively lengthy and could be more concise without losing helpful context.

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 4 parameters, no output schema, and no annotations, the description provides adequate context: prerequisites, output format, parameter details, and examples. It could be improved by describing the exact return data structure or pagination, but it is sufficient.

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 add meaning. It explains each parameter: tag_key with default, start_date/end_date with ISO format and defaults, include_ri with default. It adds value beyond the schema's property titles.

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 explicitly states 'Show exactly how much each team saved from Savings Plans and Reserved Instances' with a specific verb and resource. It distinguishes itself from other tools by solving the 'showback problem at line-item granularity' that other tools don't address.

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 provides clear context for usage, including prerequisites ('Requires CUR delivery to S3 and Athena. Team plan feature.') and multiple example queries. However, it does not explicitly state when not to use this tool or mention alternative tools.

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