| name | wiki-retrieve |
| description | Hybrid retrieval primitive for the Compound Vault. Replaces the v1.6 static hot→index→drill read order with contextual-prefix + BM25 + cosine-rerank, modeled on Anthropic's Sept 2024 Contextual Retrieval research (35-49-67% retrieval-failure reduction). Opt-in via `bash bin/setup-retrieve.sh`; feature-detected by wiki-query and autoresearch. Triggers on: retrieve, hybrid retrieval, BM25, rerank, contextual retrieval, search the chunks, chunk search, vault search, semantic search, what chunks match, find relevant passages. |
| allowed-tools | Read Bash |
wiki-retrieve: Hybrid Retrieval over the Vault
The v1.6 query path was Read(hot.md) → Read(index.md) → Read(3-5 pages) → synthesize. It worked, but page-level granularity loses to chunk-level granularity any time the answer lives in a specific passage rather than a whole page. The v1.7 wiki-retrieve skill is the chunk-level upgrade — opt-in, feature-gated, and replaces nothing if you don't run the setup.
Origin: This skill is original to claude-obsidian. There is no upstream kepano equivalent. The technique is from Anthropic's Sept 2024 Contextual Retrieval research — we implement it as agent-skill plumbing.
Data privacy (v1.7.1+)
Tier 1 (Anthropic API) and tier 2 (claude CLI subprocess) of the contextual-prefix generator send wiki page bodies off-machine. As of v1.7.1, both tiers are GATED behind explicit user consent at two layers:
scripts/contextual-prefix.py --allow-egress (default off). Without the flag, pick_prefix_tier() returns "synthetic" regardless of ANTHROPIC_API_KEY or claude binary presence.
bin/setup-retrieve.sh prompts before any non-synthetic Stage 1 run; default is abort.
To run fully on-machine (tier 3 synthetic prefix + local ollama rerank), use bash bin/setup-retrieve.sh --no-llm. This is also the effective behavior if you decline the consent prompt or omit --allow-egress.
The guard mirrors scripts/tiling-check.py:351 --allow-remote-ollama. v1.6 vaults that never provisioned this skill see zero behavior change.
Architecture
INGEST (one-time, then incremental):
wiki/<page>.md
│
▼
scripts/contextual-prefix.py
│ ├─ chunk on paragraph boundaries (~500 token target, 200 char overlap)
│ ├─ generate 1-2 sentence prefix per chunk
│ │ tier 1: ANTHROPIC_API_KEY → Anthropic API (Haiku, prompt-cached
│ │ when body ≥ ~16 KB / Haiku 4.5 floor)
│ │ tier 2: `claude` on PATH → claude -p subprocess
│ │ tier 3: synthetic → frontmatter title + first paragraph
│ └─ write .vault-meta/chunks/<address>/chunk-NNN.json
│
▼
scripts/bm25-index.py build
└─ inverted index over chunks' contextualized_text → .vault-meta/bm25/index.json
QUERY:
query string
│
▼
scripts/retrieve.py "<query>" --top 5
├─ bm25-index.py query "<query>" --top 20 (sparse candidate set)
├─ rerank.py "<query>" --candidates - (dense rerank via ollama cosine)
│ cosine(query_embedding, chunk_embedding)
│ embeddings cached in .vault-meta/embed-cache.json keyed by body_hash
└─ dedupe by page-address, return top-N candidates with absolute_path
│
▼
caller (wiki-query / autoresearch) reads the cited pages and synthesizes
Feature gating
Other skills must detect this skill before using it. The canonical detection:
[ -x scripts/retrieve.py ] && [ -d .vault-meta/chunks ] && \
[ -f .vault-meta/bm25/index.json ] && \
echo "wiki-retrieve installed" || echo "fallback: legacy hot→index→drill"
If detection fails, callers MUST fall back to the v1.6 read order. This skill never breaks the base plugin.
Setup
bash bin/setup-retrieve.sh
What it does, in order:
- Sanity-checks the 4 scripts are present and executable.
- Creates
.vault-meta/chunks/ and .vault-meta/bm25/.
- Probes ollama at
http://127.0.0.1:11434 for nomic-embed-text (rerank prerequisite). Reports status; does not install.
- Reports which contextual-prefix tier will be used (Anthropic API / claude CLI / synthetic).
- Runs
contextual-prefix.py --all to chunk + contextualize every wiki page.
- Runs
bm25-index.py build.
- Smoke-tests
retrieve.py against the query "wiki".
Flags:
--check — diagnostics only, no provisioning.
--no-llm — force tier-3 synthetic prefix (cheapest, zero LLM dependency).
--rebuild — re-chunk every page even if body_hash matches.
Cost ceiling
Per Anthropic's published research, contextual-prefix generation costs approximately $12 per 1,000 documents with Haiku + prompt caching. For a 100-page vault with ~3 chunks per page, that's ~$3.60 one-time, with incremental updates much cheaper (only changed pages re-process).
If you want to validate cost before running on a large vault:
bash bin/setup-retrieve.sh --no-llm
The claude-cli subprocess tier (no API key) is free in $ terms but slower (~3-10s per chunk depending on Haiku availability).
Skill commands (recipe)
These are the commands wiki-query and autoresearch will execute when wiki-retrieve is feature-detected. Other skills should mirror this pattern.
Standard retrieve
python3 scripts/retrieve.py "your question here" --top 5
Output: JSON with candidates array. Each candidate has absolute_path to the source page; caller reads that page (using the v1.7 transport selector) and synthesizes.
BM25-only (skip rerank)
python3 scripts/retrieve.py "query" --top 5 --no-rerank
Faster (no ollama call); lower quality.
Explain mode (debugging)
python3 scripts/retrieve.py "query" --top 5 --explain
Adds an explain block with per-stage diagnostics (BM25 candidate count, dedupe size, etc.).
Direct BM25 inspection
python3 scripts/bm25-index.py query "query" --top 10
python3 scripts/bm25-index.py stats
Rerank strategy probe
python3 scripts/rerank.py "query" --peek
Reports which strategy will run (cosine via ollama / no-op).
Integration with wiki-query
After this skill is installed, skills/wiki-query/SKILL.md standard and deep modes will:
- Read
wiki/hot.md (always — quick context).
- Call
python3 scripts/retrieve.py "<query>" --top 5.
- Read the candidate pages from the result's
absolute_path field (using the v1.7 transport selector — obsidian-cli read or Read tool).
- Synthesize with chunk-level citation.
Quick mode is unchanged (hot.md only — never invokes retrieval).
If retrieve.py exits 10 (feature not provisioned), wiki-query falls back to the legacy v1.6 Read(index.md) → Read(N pages) order. No user-visible breakage.
Index maintenance
The index is NOT auto-refreshed when wiki pages change. Re-run after substantive ingest sessions:
python3 scripts/contextual-prefix.py --all
python3 scripts/bm25-index.py build
A future v1.7.x patch will add an opt-in PostToolUse hook that triggers contextual-prefix + BM25 rebuild after every N writes. For v1.7.0, refresh is manual.
To wipe and start over:
rm -rf .vault-meta/chunks/ .vault-meta/bm25/ .vault-meta/embed-cache.json
bash bin/setup-retrieve.sh
Future tiers (v1.7.x roadmap)
Documented for transparency; not implemented in v1.7.0:
| Stage | v1.7.0 | v1.7.x target |
|---|
| Contextual prefix | API / claude-cli / synthetic | + Voyage embed-based pseudo-prefix |
| Sparse retrieval | BM25 | + SPLADE learned-sparse |
| Dense retrieval | (none — rerank-only) | Separate vector candidate set fused with BM25 (true hybrid) |
| Rerank | nomic cosine / no-op | + sentence-transformers BGE-base, Cohere Rerank, Voyage Rerank |
| Multi-vault | (single-vault) | Federation via wiki-federate (backlog #15) |
Cross-reference
How to think (10-principle mapping)
When working on this skill, apply the 10-principle loop. See skills/think/SKILL.md for the canonical framework.
| # | Principle | Application here |
|---|
| 1 | OBSERVE (ext) | Read the BM25 index state + embed cache state before issuing a query. Stale caches produce wrong answers. |
| 2 | OBSERVE (int) | Am I trusting the cache when it should have been invalidated by recent ingests? Check mtime against last ingest. |
| 3 | LISTEN | The user's query — what does it actually ask? Decompose into intent and terms before matching. |
| 4 | THINK | Which retrieval strategy fits this query? BM25-only / BM25 + rerank / contextual-prefix + BM25 + rerank. |
| 5 | CONNECT (lat) | How does this hybrid compare to v1.6 baseline? +32pp top-1 / +41% error reduction is the published delta. |
| 6 | CONNECT (sys) | --allow-egress consent gate for Anthropic API; ollama runs local-only; rerank caches under .vault-meta/. |
| 7 | FEEL | When not provisioned, exit 10 with a friendly "run bash bin/setup-retrieve.sh first" message — not a stack trace. |
| 8 | ACCEPT | When retrieval returns empty, say so honestly. Don't fabricate. Don't pad with low-confidence guesses. |
| 9 | CREATE | A ranked candidate list with --explain traceability for every score component. |
| 10 | GROW | Queries that consistently fail → content gaps in the wiki. Track those as autoresearch inputs. |