billy_outstanding

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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful output behavior beyond those hints: only approved unpaid items, grouped by original currency, and current rather than historical. It does not describe return formatting or pagination, but those are less critical given the annotation coverage.

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?

Two short sentences with no filler. The core scope is front-loaded, and the clarifying 'not a historical as-of report' comes second as a precise caveat.

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?

For a zero-parameter, read-only report tool with no output schema, this description is sufficient: it states the content, the approval/unpaid filter, the currency grouping, and the temporal nature. Nothing needed to decide whether to call it is missing.

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 tool has zero parameters and an empty schema, so there is nothing for the description to add about parameter semantics. The baseline of 4 applies because no parameter documentation is needed.

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 identifies a specific resource: current approved unpaid bills and invoices, and adds grouping by original currency. It also explicitly rules out historical as-of semantics, which helps distinguish it from sibling report tools. It lacks an explicit verb like 'list' or 'get,' but the purpose is clear.

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 phrase 'Current... Not a historical as-of report' gives an explicit temporal scope and a when-not signal, so an agent can avoid using it for historical snapshots. It does not name sibling alternatives like billy_period_overview, but the current-vs-historical distinction provides clear usage context.

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