describe_bills

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

Annotations already declare readOnlyHint=true, so the description is consistent and adds no contradictory info. It describes the query operation but does not disclose additional behavioral traits like data freshness, rate limits, or permission requirements. With annotations covering safety, the description's lack of extra detail is acceptable.

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 concise, with a clear purpose statement followed by parameter explanations. It could be more structured (e.g., bullet points or separate sections), but it is efficient and front-loaded.

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 description covers the function and parameters adequately. Since an output schema exists, the vague return description ('str: billing information') is acceptable. However, it lacks context about the scope (e.g., what user, how billing periods are determined) and does not mention any prerequisites or error conditions.

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. It provides examples and explanations for billing_cycles ('YYYY-MM'), db_instance_id (example 'rm-xxx'), and is_billing_item (boolean indicating dimension). This adds significant meaning beyond the schema, which only has 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 clearly states it queries consumption summary for a user within a billing period. It specifies the resource (product instances/billing items) and the action (query). It distinguishes from sibling describe_* tools by focusing on billing, though it could be more precise about what 'consumption summary' includes.

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. Sibling tools like describe_db_instances or describe_monitor_metrics are not mentioned, and there are no conditions for when not to use this tool. The agent must infer usage from the name alone.

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