# CPersona

> MCP memory server: persistent, searchable memory for Claude and any MCP
> host. Single local SQLite file, 3-layer hybrid retrieval (vector + FTS5 +
> keyword), zero LLM dependency — the server never calls a generative model.
> This site is the canonical documentation for the 2.5.x line; when another
> surface (README, bundled skill) disagrees, the site wins.

Key facts an agent should not guess wrong: recall responses are ordered
ascending by score (the LAST element is the best match); `store` dedup is
skip-not-upsert (changed content under a reused msg_id is NOT updated — use
update_memory); autocut is inert under the default rsf/rrf fusion modes
(set_recall_precision is the effective gate knob); profile rows carry no
score and can be cut by limit unless confidence scoring is enabled;
CPERSONA_MAX_MEMORIES is the vector scan window, not a storage cap.

## Docs

- [Getting Started](https://cloto-dev.github.io/CPersona/getting-started/): install, the embedding-server contract and its reference implementation, MCP client registration, verification
- [Roadmap](https://cloto-dev.github.io/CPersona/roadmap/): what each release line is for and may break, the planned 2.6 retrieval features and the measured problem each answers, what remains of the earlier 3.0 graph plan, and the runtime/scale ladder towards a Go index service — descriptive, not a commitment
- [Architecture](https://cloto-dev.github.io/CPersona/architecture/): component layout, SQLite/FTS5 storage, the three retrieval channels and the fusion → gate → reverse pipeline, isolation axes, zero-LLM rationale
- [Tools](https://cloto-dev.github.io/CPersona/tools/): every tool grouped by purpose, each linked to the contract it can surprise you with
- [Configuration](https://cloto-dev.github.io/CPersona/configuration/): every environment variable with defaults; HTTP transport and its authentication requirements
- [Behavior Contracts](https://cloto-dev.github.io/CPersona/behavior-contracts/): the behaviors callers may rely on — recall ordering, confidence×fusion interaction, episode boundary penalty, scan window, dedup, autocut, profile scoring, gate_fallback, lock semantics
- [FAQ](https://cloto-dev.github.io/CPersona/faq/): question-shaped index into the pages above
- [Operations Runbook](https://cloto-dev.github.io/CPersona/operations/): WAL-safe backup, degradation detection, recall tuning order, Japanese/CJK guidance, corpus indexing patterns, maintenance cadence
- [Quality Assurance](https://cloto-dev.github.io/CPersona/quality-assurance/): how a release is gated — audit rounds, the bug ledger, structural CI gates, mutation proof, and the gates that check the docs themselves

## Project standards

Normative documents. They state what a release, an audit report or a generated
policy block MUST look like, and they are written to be adopted by projects
other than this one.

- [Release lifecycle standard](https://cloto-dev.github.io/CPersona/RELEASE_LIFECYCLE_STANDARD/): tier definitions (Stable / Current), the risk-triggered pre-release ladder, support windows
- [SuperAuditor standard](https://cloto-dev.github.io/CPersona/SUPERAUDITOR_STANDARD/): the pull contract for reporting findings — severity vocabulary, cap semantics, and the deliberate silence on what a server detects
- [CLAUDE.md policy standard](https://cloto-dev.github.io/CPersona/CLAUDE_MD_POLICY_STANDARD/): how a project's skill generates a marker-wrapped policy block into always-loaded agent memory, and why a skill alone cannot carry that guarantee

## Design notes

Point-in-time records of how one behavior was decided, including the routes
that were rejected. They are not the current-state reference — where a design
note and the pages above disagree, the pages above win.

- [Per-client capabilities (ACL)](https://cloto-dev.github.io/CPersona/ACL_DESIGN/): named bearer tokens, per-agent read/write grants, deny-by-default
- [OAuth support](https://cloto-dev.github.io/CPersona/OAUTH_DESIGN/): resource-server metadata and token verification, the three routes weighed and why issuance is delegated to an external provider, the per-subject boundary
- [Server-served operating context](https://cloto-dev.github.io/CPersona/OPERATING_CONTEXT_DESIGN/): distributing operator instructions to all connected MCP clients
- [Declared session identity](https://cloto-dev.github.io/CPersona/SESSION_IDENTITY_DESIGN/): the declared `session_key`, why one process is not one session under streamable-HTTP, and which process-global state it re-partitions
- [Recorded access origin](https://cloto-dev.github.io/CPersona/MEMORY_ORIGIN_DESIGN/): recording the observed caller on each stored row, for the paths where `agent_id` names nobody
- [Recall preview tier](https://cloto-dev.github.io/CPersona/RECALL_PREVIEW_TIER_DESIGN/): preview truncation and the get_contents expansion path
- [Contiguous embedding index](https://cloto-dev.github.io/CPersona/CONTIGUOUS_INDEX_DESIGN/): moving the vector scan's read off SQLite rows onto a contiguous sidecar, with bit-identical answers
- [Reach and recency in the scan window](https://cloto-dev.github.io/CPersona/SCAN_WINDOW_REACH_DESIGN/): why widening the vector scan window loses recent answers, and the second ranked list that lets reach move without removing the recency prior
- [Embedding degradation advisory](https://cloto-dev.github.io/CPersona/DEGRADED_ADVISORY_DESIGN/): how recall reports a dead embedding layer instead of silently degrading

## Optional

- [Sponsorship](https://cloto-dev.github.io/CPersona/sponsorship/): what sponsoring does and does not buy, where it goes, and the ways to help that cost nothing
- [Repository](https://github.com/Cloto-dev/cpersona): source, README quick start, issues
- [PyPI](https://pypi.org/project/cpersona/): pip / uvx installation
- [Bundled agent skill](https://github.com/Cloto-dev/cpersona/tree/master/skills/cpersona-memory): teaches an MCP agent the store / recall / archive workflow and the CLAUDE.md policy block