What the documents look like
Export tax rebate filing happens after goods leave the country, and the work is matching tax vouchers rather than clearing customs. The materials in scope are the export tax exemption and rebate filing form, the export customs declaration, the purchase invoice, and the foreign exchange receipt voucher. These come from the electronic tax bureau, the export rebate filing system, customs electronic information, and the finance ledger. This page addresses one task: comparing contracts and transaction materials. Tool calls and plugins decide, inside an orchestration, whether the model invokes a comparison tool based on the tool description and parameters. Materials update monthly or per batch, so each batch needs its own check of subject, period, and fields.
Three facts shape this task. First, the comparison is a post-export voucher match, so the declaration and the purchase invoice describe the same shipment from different sides and must be read together. Second, the filing form, declaration, invoice, and receipt voucher are separate documents with separate issuers, so a field present in one is not automatically present in another. Third, the batch is the natural unit, which means the model needs the batch boundary before it can decide whether a comparison tool applies.
Constraints at the tool calls step
A tool description tells the model what the tool does. It needs to state the input conditions and the situations in which the tool should not be called. System module parameters are fixed; plugin parameters are configurable. The parameter description and the must-have flag together influence whether the model calls the tool. When a required parameter has no suitable value in context, the model may decline to call, and prompt wording can guide the user to supply it; the actual request still needs checking. In advanced orchestration, available tools are connected to the tool call module, and a small set of tools is easier to tune before adding more. The tool call termination node ends the current call, stops further tool calls, and stops the AI from summarizing tool results.
Hypothetical paper exercise sample. A foreign trade enterprise accountant checks one export customs declaration against one purchase invoice for the March 2025 batch. The declaration text reads: "Domestic consignor: Company A; commodity: cotton women's shirts; quantity: 1,200 pieces; export date: February 18, 2025." The purchase invoice text reads: "Buyer: Company A; goods: cotton women's shirts; quantity: 1,200 pieces; invoice date: February 10, 2025." A proposed sentence reads: "The declaration and purchase invoice quantities for this batch agree, so the comparison can be submitted." The request awaiting a decision reads: "Please call the comparison tool to confirm that the contract and transaction materials for this batch agree." The sample is for paper checking only and does not indicate that anything was submitted or compared.
Configuration and implementation checks
| Configuration item | Hypothetical starting point for this exercise | Comparison method |
|---|---|---|
| Tool description | State that the comparison covers subject, commodity, and quantity across the declaration and purchase invoice | Compare item by item against the sample proposed sentence |
| Tool parameters | Subject, commodity, quantity, and date as input parameters | Check which parameters are required and what the actual request contains |
| Required parameters | Subject and quantity marked as required | Observe whether a call occurs when a parameter is missing |
| Tool connection | Only the comparison tool connected | Add more only after tuning |
| Tool call termination | Placed after the comparison tool | Observe whether AI summarization stops |
| Custom variables | Parameter description filled for nodes not recognized as tool parameters | Check whether the node is invoked |
The starting point uses few tools so that tuning follows the description.
Three common errors
- The tool description omits the situations where the tool should not be called, and the model may fabricate a parameter for a context that has none. Check the input description text, compare whether it states input conditions, and observe whether the model still calls when the subject is absent.
- The parameter description is treated as a guarantee of execution, and the actual request is never checked. Check which parameters are required, compare the sample subject and quantity, and observe whether the model declines to call when a required parameter is missing.
- Retrieval or a form is treated as authorized execution. Check the request awaiting a decision, compare the authorization state, and observe whether any approval or write record exists; when it is absent, record the gap.
How to verify the setup
- Enter the sample declaration and purchase invoice texts, compare the four fields of subject, commodity, quantity, and date. The proposed sentence "quantities agree" is supported on the quantity field; the date and subject still need checking, and anything not stated is recorded as pending verification.
- Enter the request awaiting a decision, compare the tool description and required parameters, and observe whether the model calls the comparison tool when subject and quantity are complete, and whether it declines when a parameter is missing.
- Enter the tool call termination node, compare before and after termination, and observe whether AI summarization stops after termination; behavior not observed is recorded as unknown.