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

Annotations already disclose that this is a write operation, idempotent, and potentially destructive. The description adds useful auth context by stating that asset_costs:write scope is required. It does not explain what is destroyed by a destructive update or how omitted fields are treated, so it adds some but not rich behavioral context beyond 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 focused sentences with no wasted text. The primary action and target are front-loaded, followed by the auth requirement. It is appropriately sized for a tool whose parameter details live in a rich schema.

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 13-parameter mutation tool with no output schema, the description covers purpose, record type, and scopes. However, it does not clarify partial-update semantics, what happens to omitted fields, or the significance of the destructive annotation. The schema and annotations carry much of the burden, but the description leaves meaningful update behavior unstated.

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 the schema already documents all 13 parameters. The description only reiterates that the operation targets an entry by ID and does not add additional semantics for fields like vendor_id, purchase_order_id, or cost_date beyond what the schema provides. Baseline 3 is appropriate.

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 states a specific verb and resource: updating an existing asset cost entry by ID. It also adds domain context by tying the record type to the AssetLab Expenses page, which helps distinguish it from nearby resources. It stops short of naming sibling tools such as update_infrastructure_asset_cost or update_expense, so it is clear but not maximally differentiated.

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 'update an existing' implies this is the mutation path for asset costs, and the scope requirement gives a precondition for use. However, the description does not explicitly say when to use this versus create_asset_cost, get_asset_cost, or update_expense. Usage is therefore implied rather than spelled out.

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