# Concepts

HYTHE stores recorded knowledge and project state for MCP-compatible agents. It does not decide whether a claim is true or guarantee that a model follows instructions.

## Current observations

An entity is a named subject. Its observations record evidence and decisions. Add a correction that explicitly supersedes the earlier observation, or use `replace-current`. `get_current_observation` resolves the current observation on the server. Entity definition snapshots are not a current-state feed.

## Current project state

A checkpoint captures objective, status, owner, next actions, blockers, and guardrails for an exact project or task scope. A current pointer identifies the accepted checkpoint. An ordinary write extending that checkpoint advances it; a write against an older parent remains a branch and does not replace the accepted state merely because its revision is higher.

## Reconciliation and partial updates

Reconciliation explicitly names the live heads and current pointer, selects a survivor, and resolves divergent values. Historical snapshots remain recorded. In v3, `record` writes facts or loops without resending state, while `patch` applies a merge patch. Both require the current pointed parent; stale requests return a conflict rather than creating a branch.

## Resume and coverage

`resume` reconstructs context under a token budget. Each section reports what was included, what exists, and why anything was omitted. With `resultVersion: 3`, facts and loops come from the accepted checkpoint lineage and carry provenance. Divergent and legacy values are reported separately. Reading v3 does not automatically reconcile an older scope.

## Handoffs and identity

Agents send explicit messages and read their own inboxes. Read and archive state describe what the server recorded, not a guarantee that a model understood or acted. Stable identities give attribution and inbox ownership. They do not isolate shared project memory or the filesystem. Server-enforced per-agent identity depends on credential and authorization mode configuration.

## Evidence

See the [v3 contracts](https://github.com/hythe-dev/hythe/blob/v0.2.0/docs/CHECKPOINT-RESUME-V3.md) and [security model](https://github.com/hythe-dev/hythe/blob/v0.2.0/SECURITY.md). Observation supersession and checkpoint selection are separate mechanisms; neither is a universal last-writer-wins rule.