Plane 01 / 06
Context Plane
Assembles exactly what the model is allowed to see, inside a fixed token budget, and records where every token came from.
- Guarantee
- Every prompt is built from a manifest of addressed, access-checked sources — nothing enters the window that cannot be traced back to a document version and the caller's entitlement.
- Contains
- Hallucinated grounding, cross-tenant leakage and silent prompt bloat.
- Ledger fields
- context_manifest_hash
- source_ids[]
- entitlement_scope
- window_tokens
Hybrid retrieval
BM25 and dense vectors are queried in parallel, merged with reciprocal-rank fusion, then re-scored by a cross-encoder so exact identifiers (policy numbers, CPT codes) are never lost to semantic similarity.
Entitlement-aware filtering
Document ACLs are denormalised into the index as filter attributes and applied inside the vector query, so a chunk the caller cannot open is never scored, let alone returned.
Window budgeting
Each prompt segment (system, policy, evidence, history, tool output) has a token ceiling; overflow is resolved by relevance-ranked eviction and extractive compression, never by truncating the tail.
Tiered memory
Session memory lives in a TTL-bound store, durable memory requires an explicit write with a retention class, and both are retrieved through the same entitlement filter as documents.
Provenance chains
Every chunk carries (source URI, document version hash, byte offsets, ingest job id); the ordered list is hashed into a context manifest that the ledger entry references.
Freshness contracts
Sources declare a maximum staleness; the ingest scheduler raises an alert and the retriever down-ranks any chunk whose document version is older than its contract allows.