record_saleMark inventory sold + record sale proceeds with gain/loss. ($0.10; API key required)
| Name | Required | Description | Default |
|---|---|---|---|
| amount | Yes | ||
| sold_at | No | ||
| currency | No | ||
| request_id | No | Client idempotency key (retries return original result). | |
| inventory_id | Yes | ||
| idempotency_key | No | Alias for request_id. |
| Name | Required | Description | Default |
|---|---|---|---|
| message | No | ||
| expense_id | No | ||
| inventory_id | No | ||
| realized_gain_loss | No |
Changes observed during successful MCP inspections.
Input schema / properties / idempotency_keyAdded value: +{
+ "description": "Alias for request_id.",
+ "type": "string"
+}Input schema / properties / request_idAdded value: +{
+ "description": "Client idempotency key (retries return original result).",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only indicate non-read-only and non-destructive, so the description adds meaningful behavior: it mutates inventory state, records financial proceeds, computes gain/loss, and requires an API key at a $0.10 cost. It does not mention idempotency or what happens if the inventory is already sold, but those are partially covered by schema fields and the added context is valuable.
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 short, front-loaded sentences. Every phrase earns its place: the core action, the financial outcome, the cost, and the auth requirement. No filler or redundant restatement of the tool name.
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 mutating financial/inventory tool with six parameters, the description covers the essential action and operational cost but leaves ambiguity around optional parameters, currency defaults, and preconditions such as whether the inventory item must exist and be unsold. The presence of an output schema reduces the need to explain return values, but the missing parameter context prevents a higher score.
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 only 33%, with amount, sold_at, currency, and inventory_id undocumented. The description clarifies amount as sale proceeds and inventory_id as the item to mark sold, but it does not explain currency format, sold_at meaning, or whether amount is gross proceeds. This is insufficient to compensate for the low schema coverage.
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 uses a specific verb ('record') with a clear resource ('sale') and states the core effects: marking inventory sold and recording sale proceeds with gain/loss. This distinguishes it from sibling tools like record_purchase and log_transaction without needing to open the 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?
The phrase 'Mark inventory sold' clearly establishes when to use this tool, and the cost/API-key note adds operational context. However, it does not explicitly state when not to use it or name alternatives such as record_purchase or log_transaction, leaving some routing to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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