bill_summary

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

With no annotations, the description must disclose behavioral traits. It only states what the tool returns, not data freshness, idempotency, authentication requirements, or error handling. For a data retrieval tool, more transparency is needed.

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 sentence, which is brief but not overly concise given the lack of detail. It front-loads the core purpose but could benefit from additional context without being verbose.

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?

Despite having an output schema, the description is too sparse. It does not explain what 'per fuel' entails (e.g., electricity, gas), nor does it provide guidance on typical use cases or examples. The overall context is incomplete for a tool with a single complex parameter.

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 compensate but fails to mention the period parameter at all. The parameter semantics are entirely dependent on the schema, which provides only structural definitions without usage hints.

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?

Description clearly states the tool returns total cost per fuel for a period. It implies a breakdown by fuel type, distinguishing it from siblings like get_consumption_raw or compare_tariff. However, it does not specify the output format, which is mitigated by the existence of an output schema.

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 alternatives such as get_consumption_raw or usage_breakdown. The description lacks any when-to-use or when-not-to-use context.

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