build_additive_breakdown

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

Annotations already declare readOnlyHint and openWorldHint. The description adds specific behavioral context: if complete is false, the identity cannot be validated even when components sum nearly to the total, and missing components are not zero or implicitly included. This aligns with the openWorldHint and provides useful nuance beyond 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?

The description is two concise sentences, front-loaded with the primary purpose. It avoids repetition and each sentence earns its place by adding either the core action or critical behavioral caveats.

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?

Although an output schema exists (so return format is covered), the description is incomplete for successful invocation. It fails to explain the parameters, making it unclear what indicator_code, country, year, and relationship_id should contain. The reference to additive_hierarchy is vague without guidance on how to use it. The tool's name implies building a breakdown, but the description only says 'check', creating uncertainty about expected behavior.

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%, meaning no parameter descriptions exist in the schema. The description does not explain any of the four parameters (year, country, indicator_code, relationship_id) or their formats, meanings, or defaults. It only mentions 'country-year' and references additive_hierarchy, leaving the agent without guidance on how to populate the parameters.

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's purpose: checking a current-NCU accounting total for one country-year. It names the resource and the action, and references the sibling additive_hierarchy for selecting a relationship, which helps differentiate it. However, the name suggests 'building' a breakdown while the description says 'check', creating slight ambiguity about the primary action.

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 advises using additive_hierarchy to choose a relationship, providing some usage direction. It also explains a condition (complete=false) that affects validation interpretation. However, it does not explicitly state when to use this tool versus alternatives, nor does it give exclusions or alternative tools for similar tasks.

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