Reference only; verify against the target FastGPT release and deployment documentation.
What This Category of Data Looks Like
Data for policy and regulatory basis Q&A for building construction general contracting comes mainly from normative documents issued by the Ministry of Housing and Urban-Rural Development, provincial and municipal housing construction authorities, standard general contract documents, and local construction rules. The data has no fixed update cycle. National policy updates occur every six months to one year. Local policies are adjusted irregularly based on local construction requirements. Most documents are structured official texts. They include fields such as document number, issuing authority, effective date, clause content, and scope of application. Clauses are segmented by numbering. Common units include "article", "paragraph", "item", and date formats.
What Constraints Do These Characteristics Impose on the Vector Model and Indexing Link
These data characteristics impose clear constraints on the vector model and indexing link. First, structured clause numbering and segmentation require chunking to retain full clause integrity. Do not cut content across clauses. Doing so causes retrieval matching to fail, and prevents accurate association between policy clauses and query questions. Second, include metadata fields (document number, effective date, applicable region) in index metadata. Use this metadata for precise filtering in subsequent steps. This ensures returned policies match user regional and timeliness requirements. No fixed update cycle requires indexes to support incremental synchronization. Only update new or modified policy files. This avoids full reindexing, which consumes excessive computing resources. Single policy files have long length. Limit the maximum length of single chunk content. This prevents vector dimension overload that reduces retrieval accuracy.
How to Set Configurations
| Configuration Item | Recommended Setting | Rationale |
|---|---|---|
| Chunk Length | 800–1200 characters | Matches the average length of building construction policy clauses, avoids chunks that are too long or too short |
| Overlap Length | 50–100 characters | Retains contextual connection between adjacent clauses, prevents chunking from breaking clause logic |
| Similarity Threshold | 0.75–0.85 | Filters low-match irrelevant policy clauses, aligns with the strict nature of official documents |
| Single Search Limit | Top 8 results | Controls the number of returned results, avoids context overflow |
| maxToken | 4096 | Aligns with the input length limit of mainstream vector models, ensures retrieval results can be fully embedded in context |
| defaultToken | 2048 | Serves as the default context length, balances retrieval efficiency and answer completeness |
Three Common Mistakes
- No optional options appear in the interface index model dropdown, making model configuration impossible. Cause: The service address of the local vector model is not configured, or the corresponding service is not running normally, so the frontend cannot pull the available model list.
- Retrieved policy clauses have cross-chunk cut content, making it impossible to fully understand the policy intent. Cause: Chunk length is set too small, or chunking is not done according to clause boundaries, destroying the logical integrity of the policy text.
- Retrieval results include expired policy documents that do not match current construction requirements. Cause: The effective date field is not included in the index metadata filtering rules, and valid policies are not screened based on effective date.
How to Confirm Proper Configuration
- Upload a local building construction policy document, run a manual chunking test, check if the chunked content retains complete clauses with no cross-clause cutting.
- Enter a query targeting a specific regional policy, check if the applicable scope of the returned results matches the entered regional keywords.
- Check the index task running logs, confirm that only new or modified policy files are synced, with no abnormal records of full reindexing.
- Enter a query, check if the similarity scores of the returned results fall within the set threshold range, with no irrelevant results of too low matching degree.
The values provided are common starting points and should be measured against the reader's own samples.
Question material comes from public community discussions. Configuration values are common starting points and should be measured against your own samples. Verified on 2026-09-28.