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

Annotations only declare the generic create profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=false). The description adds two genuinely useful facts beyond them: work_order_number is derived server-side from work_order_id, and the call requires the infrastructure_asset_costs:write scope.

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?

Three short sentences, front-loaded with the action, then the derived-field caveat, then the auth requirement. No filler, though the constraint sentence could be phrased more compactly.

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 an 8-parameter mutation with no output schema, the description covers the two things an agent could get wrong (auth scope, derived field) while the schema carries field-level detail. It omits any note about what the created cost affects (e.g., purchase order balances), which is documented per-parameter instead.

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 baseline is 3, but the description adds semantics the schema cannot express: the server-side derivation relationship between work_order_number and work_order_id. It does not touch purchase_order_id's balance effect, which is already documented in the schema.

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 and resource ('Record a cost against an infrastructure feature'), which cleanly separates it from the many sibling create_* tools. It does not explicitly name the nearest alternative (create_asset_cost), so differentiation relies on the agent noticing the 'infrastructure feature' scope.

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?

There is a directive ('do not set work_order_number'), but no guidance on when to use this tool versus create_asset_cost, create_expense, or create_invoice, and no prerequisites beyond the scope mention. The agent must infer selection 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.