2dph/docs/design.md

type, status, related

type	status	related
explanation	current	docs/README.md docs/runbook.md docs/roadmap.md

Design — facts, info, deduction

Two roots, one transaction

root — facts | info — is a column on every node and edge. Both roots live in the same Ladybug file and are written inside the same transaction (D12). Splitting is semantic, not physical:

• facts — assertions backed by ≥2 independent sources (confidence: confirmed) or marked partial/hypothesis when the second source is missing.
• info — narrative/descriptive leafs (how-tos, READMEs, notes). Searchable, never asserted as an answer.

ACID: Ladybug commits facts + info atomically; the audit can treat a snapshot as one consistent state.

Deduction search

bin/brain/search.go "question"
  1. facts root   — confirmed answers only   → return with evidence links
  2. info  root   — supporting narrative     → snippets, marked (not confirmed)
  3. web-search   — second independent source → upgrade hypothesis to confirmed
     (`web` block from `bin/web/search.go` when no facts hit; status `throttled`
     is not evidence of absence; `--no-web` / `--root` skip it)

--hop N walks Leaf-[:FROM_FILE]->File-[:HAS_VERSION]->Commit-[:AUTHORED]->Person from each hit (1=File, 2=Commit, 3=Person). Rebuild writes FROM_FILE; git import writes HAS_VERSION/AUTHORED (#17).

Go CLIs parse with flaggy via internal/cli (D23). Flags may appear after positionals (search q --hop 1). Completions: source <(./bin/cli/complete.go bash).

Who / What / How / Where / When + evidence

Every assertion edge carries:

prop	meaning
who	subject/object persons, services, hosts
what	the associated subjects/objects (predicate)
how	methods used to read it (compose file? docker ps? ssh config?)
where	environment + filesystem path / host
when	timestamp / source_rev (git commit, mtime)
evidence	≥2 source refs (compose path, runtime container, config)
confidence	confirmed / partial / hypothesis
root	facts / info

Versioning — nothing is timeless

Content leafs: sha256, observed_at, source_rev, confidence. Stale = a file changed on disk (git HEAD/mtime) after its last observed source_rev. File-[:HAS_VERSION]->Commit-[:AUTHORED]->Person records the history of every content leaf. Commit records come from bin/git/import.go (go-git, no git binary); conversion prints leafs, brain write is bin/brain/index.go.

bin/facts/audit stale flags leafs whose observed revision is behind the corpus HEAD.

Sources (auto-pairing)

• A: runtime state — docker ps (container running), ports actually bound
• B: declared config — docker-compose.yml, ~/.ssh/config, homeserver.yaml
• C: narrative — READMEs, AGENTS.md, docs

Confirmed = A×B or B×C agreement. Single source = hypothesis + (not confirmed). Conflicting pairings (≥2 yes vs ≥2 no) stay hypothesis until temporal_freshness or authority_pairing fires (bin/facts/audit contradict, #29).

Read path

bin/brain/get.go, stats.go, and eval.go call internal/brain with cgo (system_ladybug), compiled by Zig (bin/cgo/zcc, D21), not gcc. They do not exec Python. Control questions for recall@5 live in internal/brain/rank so CI can test the table without libladybug. Python bin/kb/{get,stats,eval} remain for GitHub Actions until the runner fetches Zig + libs (bin/cgo/zig). Incremental write is bin/kb/add (bin/brain/add.go). Bulk index/write is still bin/kb/index (docker compose --profile index).

Agent API (D20)

bin/brain/serve.go exposes the same internal/httpapi.Ops table as OpenAPI (GET /openapi.json) and MCP (POST /mcp JSON-RPC tools/list + tools/call). Tool names match paths: search, get, stats, audit, ingest (add a leaf; omit body for the CLI hint). Agents should use these endpoints instead of shebang CLIs.

Reasoner (D18)

Pluggable OpenAI-compatible URL. RAM: Qwen/Qwen3.5-9B. Quality: prism-ml/Bonsai-27B-gguf or Qwen/Qwen3.6-27B. No official Qwen3.6-9B. CPU sidecar: compose profile reasoner (OLLAMA_NUM_GPU=0, 127.0.0.1:11435). Bake-off: bin/reasoner/bakeoff.go. Weights stay out of the 2dph image. See docs/reasoner.md.

Gap to v1 (hops, corpus, CI eval): roadmap, epic #16.