What data for this category looks like
Data for policy and regulatory basis Q&A in the construction machinery sector comes primarily from equipment manufacturing support policies, industry standard specifications, and project approval documents released by the State Council, the Ministry of Industry and Information Technology, and provincial and municipal state-owned assets supervision and administration commissions. Most data is stored as PDF or official web documents.
Document structures include fields such as policy document number, issuing authority, effective date, scope of application, specific clauses, and reward and punishment rules. Single-document length varies widely. Updates follow the rhythm of policy releases, with no fixed publication cycle.
What constraints these characteristics impose on the vector models and indexing link
Construction machinery policy documents contain many specialized terms, have wide variation in single-document length, and include clear metadata fields. This requires the indexing link to retain complete metadata to distinguish different policy clauses.
Single documents that are too long will exceed vector model input limits. Set chunking parameters reasonably to avoid semantic fragmentation.
Policy updates have no fixed cycle. Support incremental indexing to reduce redundant computation.
Semantic matching for specialized terms requires vector models adapted to industry characteristics, to avoid matching bias from general-purpose models.
How to set configurations
| Configuration Item | Recommended Value | Rationale |
|---|---|---|
| Chunk Length | 800–1200 characters | Construction machinery policy documents have long individual clauses. Too short chunking will split policy logic. Too long will exceed vector model input limits. This setting is based on actual testing. |
| Overlap Length | 100–150 characters | Preserve semantic connections between adjacent chunks. Avoid incomplete matching of questions after policy clauses are truncated. |
| Similarity Threshold | 0.75–0.85 | Policy content is highly specialized. Filter low-match irrelevant results. Avoid confusing policy clauses with different document numbers. |
| Single Search Limit | Top 3–5 results | Policy Q&A requires precise matching of corresponding clauses. Too many results will increase context processing load. |
maxToken | 4096 token | Adapt to the input limit of mainstream open-source vector models. Ensure complete extraction of semantic features from policy chunks. |
defaultToken | Adjust based on actual document length | Reserve sufficient token space to store metadata and chunk content for ultra-long policy documents. |
| Vector Model | Open-source vector model adapted to professional domains | Construction machinery policies contain many industry-specific terms. General-purpose vector models cannot accurately capture semantic features of policy clauses. |
Three Common Mistakes
- Phenomenon: Knowledge base indexing progress stalls. Unfinished files show a "processing" status beyond the preset duration. Cause: Did not configure reasonable chunking and timeout parameters for the long text characteristics of construction machinery policy documents. Full indexing tasks timed out without completion.
- Phenomenon: Matching results returned by the vector model do not match the professional wording of policy clauses. Semantic deviation occurs. Cause: Did not switch to a domain-adapted vector model. General-purpose vector models cannot accurately capture specialized terms in construction machinery industry policies.
- Phenomenon: After calling the file upload API, cannot determine whether indexing is complete via the interface. Cause: Did not enable the indexing status callback mechanism of FastGPT v4.17.0. Did not configure the status marking field after file processing is complete.
How to Confirm Proper Configuration
- Upload a test construction machinery policy document. View the chunk preview interface. Confirm that core policy clauses are not split.
- Submit a test question related to policy. Check the number of matching results in the retrieval output. Confirm it matches the preset single search limit.
- After calling the file upload interface, use the system-provided status query interface to verify indexing completion status. Confirm the callback logic works correctly.
- After replacing the vector model, compare matching results from different models. Confirm semantic matching meets the requirements of professional policy scenarios.
The values listed here are common starting points. They should be validated using local test data.
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.