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

Annotations already declare readOnlyHint/idempotent/non-destructive, so the safety profile is covered; the description adds real extra context by disclosing the returned field set and warning that amounts carry no currency, with an explicit remediation path (call get_organization_settings for currency_code). It does not mention pagination defaults, though the schema does.

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?

Front-loads what the tool lists, then the sibling distinction, then filters, then the currency caveat — a sensible priority order. It is somewhat dense and the 'AssetLab UI main Expenses page (top-level nav)' reference is UI-mapping detail that adds little for an agent, slightly diluting the economy.

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?

With no output schema, the description properly compensates by enumerating the record fields and flagging the currency ambiguity, which is exactly the kind of gap an agent would otherwise hit. The only missing pieces are pagination behavior and disambiguation from the infrastructure-asset cost list tool.

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 100%, so all six parameters including page/per_page are already documented. The description restates the filterable dimensions (asset, site, category, work order) without adding syntax or valid-value detail beyond the schema's enum, so it meets but does not exceed the baseline.

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?

States a specific verb+resource (list asset cost records) and enumerates the returned fields, then explicitly distinguishes itself from list_expenses by contrast ('project-scoped expenses without invoice/PO fields'). An agent can tell it apart from both list_expenses and list_infrastructure_asset_costs without opening a 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?

Gives clear routing guidance: it names list_expenses as the alternative and the distinguishing condition (project-scoped, no invoice/PO fields), and states the available filter dimensions. It stops short of naming list_infrastructure_asset_costs, the closest sibling, so the when-not coverage is incomplete.

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