wiki-synthesize — Claude Code skill: wiki synthesis pages
Scans an Obsidian vault for concepts that keep co-occurring but have no page tying them together, then scores the pairs and drafts cross-cutting synthesis pages.
npx skills add Ar9av/obsidian-wiki --skill wiki-synthesize -a claude-codeWhat wiki-synthesize does
The skill walks an Obsidian vault looking for concepts that show up on the same pages while nothing links them directly. It builds a co-occurrence map first: [[wikilinks]], tags and category from frontmatter, then a count of how many pages reference both A and B. A pair scores higher when the two concepts sit in different categories, or when a synthesis would settle a contradiction the wiki already flagged.
After that it runs in stages. It resolves config, reads index.md, hot.md and _meta/taxonomy.md, drops pairs already covered in synthesis/, and keeps the top 5 candidates. Each new page is titled A × B and carries a section for the strongest objection plus a testable search query; the concept pages get a back-link in return. Pairs left unwritten come back in the report so you can pick them up next run.
Two things have to be in place beforehand: the vault path in OBSIDIAN_VAULT_PATH and the obsidian-wiki CLI, since the closing obsidian-wiki memory sync WIKI_SYNTHESIZE call updates the index, log and hot cache through it. Backlink lookups use rg, so ripgrep needs to be installed too. Treat the objection section as a real gate: if the connection falls apart under it, the page stays a draft.
What it helps with
- find concept pairs that co-occur constantly but share no page
- filter out topics already handled in
synthesis/ - build a co-occurrence map from links and tags
- add back-links from both concept pages
- collect skipped candidates for a later run
Example prompts for the agent
- Scan the vault and create synthesis pages for the five most frequent concept pairs
- Synthesize everything about observability
- Show which pairs co-occur but aren't linked yet, and what you skipped last time
How to install wiki-synthesize
1Skills CLI (Vercel)
npx skills add Ar9av/obsidian-wiki --skill wiki-synthesize -a claude-code2Manually: put the files in place
~/.claude/skills/wiki-synthesize/SKILL.mdCopy the whole skill folder; for one project use .claude/skills/wiki-synthesize/
1Skills CLI (Vercel)
npx skills add Ar9av/obsidian-wiki --skill wiki-synthesize -a codex2Manually: put the files in place
.agents/skills/wiki-synthesize/SKILL.mdFor all projects use ~/.agents/skills/
1Skills CLI (Vercel)
npx skills add Ar9av/obsidian-wiki --skill wiki-synthesize -a cursor2Manually: put the files in place
.cursor/skills/wiki-synthesize/SKILL.mdCursor also reads .agents/skills/ and .claude/skills/
1GitHub CLI
gh skill install Ar9av/obsidian-wiki wiki-synthesize2Manually: put the files in place
.github/skills/wiki-synthesize/SKILL.md1Skills CLI (Vercel)
npx skills add Ar9av/obsidian-wiki --skill wiki-synthesize -a gemini-cli2Platform CLI
gemini skills install https://github.com/Ar9av/obsidian-wiki --path .skills/wiki-synthesizeManually: put the files in place
.devin/skills/wiki-synthesize/SKILL.mdThe legacy .windsurf/skills/ path still works
Skills CLI (Vercel)
npx skills add Ar9av/obsidian-wiki --skill wiki-synthesize -a opencodeClaude.ai
Zip the folder and upload it in Settings → Capabilities → Skills
Step by step, with commands for each platform: How to install skills in Claude Code: five ways
Questions about wiki-synthesize
How do I install wiki-synthesize in Claude Code?
Run npx skills add Ar9av/obsidian-wiki --skill wiki-synthesize -a claude-code. The skill lands at ~/.claude/skills/wiki-synthesize/SKILL.md and is picked up in the next session.
What does wiki-synthesize do?
It finds concepts that recur on the same pages without a shared synthesis page, scores those pairs, and writes cross-cutting pages for the best ones, linking back from the source pages.
What does the skill need to work?
The vault path in OBSIDIAN_VAULT_PATH and the obsidian-wiki CLI for syncing the index, log and hot cache. Backlink lookups rely on rg.
Source text
SKILL.md · MIT
---
name: wiki-synthesize
description: >
Find recurring concept combinations across the wiki that lack an explicit synthesis page, then create cross-cutting synthesis pages. Use for knowledge synthesis after the vault has accumulated enough material.
---
# Wiki Synthesize — First-Class Synthesis Discovery
You are scanning the wiki for concepts that co-occur across many pages but have no dedicated synthesis page connecting them. Your job is to surface these gaps and fill the most valuable ones with cross-cutting synthesis pages.
## Before You Start
**Writing profile:** Before drafting or rewriting natural-language Markdown, read and apply the `Writing Profile Resolution` section in `llm-wiki/SKILL.md`. Framework schema, provenance, safety, and operation-specific requirements take precedence.
`WRITING.md` preferences apply only to newly drafted or rewritten natural-language Markdown; preserve source content and structured records.
1. **Resolve config** — follow the Config Resolution Protocol in `llm-wiki/SKILL.md` (inline `@name` override → walk up CWD for `.env` → global config → prompt setup). This gives `OBSIDIAN_VAULT_PATH` and `OBSIDIAN_LINK_FORMAT` (default: `wikilink`).
2. Read `index.md` to get the full page inventory.
3. Read `hot.md` if it exists — it surfaces recent activity and active threads that may already point to synthesis opportunities.
4. Read `_meta/taxonomy.md` to understand the tag vocabulary.
When writing internal links in synthesis pages, apply the link format from `llm-wiki/SKILL.md` (Link Format section) using the `OBSIDIAN_LINK_FORMAT` value.
## Step 1: Build the Co-occurrence Map
Scan every non-special page in the vault (skip `index.md`, `log.md`, `hot.md`, `_insights.md`, `_meta/*`, `_archives/*`, `_raw/*`).
For each page, collect:
- All `[[wikilinks]]` it contains (outgoing links)
- Its `tags` frontmatter
- Its `category` frontmatter
Build a co-occurrence matrix: for every pair of concept/entity pages (A, B), count how many other pages link to **both** A and B. This is their co-occurrence score.
You don't need to be exhaustive — aim for the top 20-30 pairs by co-occurrence score. Use Grep to find backlinks efficiently:
```bash
rg -l --glob '*.md' "\[\[ConceptA\]\]" "$OBSIDIAN_VAULT_PATH"
```
Run this for your top candidate concepts and intersect the result sets.
## Step 2: Filter Out Already-Synthesized Pairs
Check the `synthesis/` directory for existing pages. For each existing synthesis page:
- Read its `sources` frontmatter or its body for `[[wikilinks]]`
- Mark those concept pairs as already covered
Remove covered pairs from your candidate list.
## Step 3: Score and Rank Candidates
For each remaining candidate pair (or cluster of 3+), assign a synthesis value score:
| Signal | Points |
|---|---|
| Co-occurrence count ≥ 5 | +3 |
| Co-occurrence count 3-4 | +2 |
| Co-occurrence count 1-2 | +1 |
| Concepts are in different categories (cross-domain) | +2 |
| Concepts share tags but live in different folders | +1 |
| One or both concepts are tagged as hubs in `_insights.md` | +1 |
| A synthesis would resolve a flagged contradiction | +2 |
Pick the top 5 candidates. If the user asked for a specific topic ("synthesize everything about observability"), filter candidates to that domain first.
## Step 4: Draft Synthesis Pages
For each top candidate, create a page in `synthesis/` using this template:
```markdown
---
title: <Concept A> × <Concept B>
category: synthesis
tags: [<shared tags>, <domain tags>]
sources: [<all pages that link to both>]
created: TIMESTAMP
updated: TIMESTAMP
summary: "Cross-cutting synthesis of how <A> and <B> interact, with implications for <domain>."
provenance:
extracted: 0.2
inferred: 0.7
ambiguous: 0.1
base_confidence: <min(base_confidence of all input pages)>
lifecycle: draft
lifecycle_changed: TIMESTAMP_DATE
---
# <Concept A> × <Concept B>
## The Connection
*What makes these two concepts worth synthesizing together — the non-obvious relationship that pages about each individually don't capture.*
## Where They Co-occur
*The pages and contexts where both appear. What situations bring them together.*
## Cross-cutting Insight
*The conclusion that only becomes visible when you look at both together. This is the point of the page — the thing you couldn't see from either concept page alone.*
## Tensions and Trade-offs
*Where the two concepts pull in opposite directions. Unresolved contradictions. Cases where applying one undermines the other.*
## Strongest Objection
*The best skeptical reading of THIS page's cross-cutting insight — the case a sharp critic would make that the connection is spurious, overstated, or an artifact of how the sources were written. Follow it with a testable search query (e.g. `> test: does X actually hold when Y is controlled for?`), never an invented citation. A synthesis that can't name its own strongest objection hasn't earned its conclusion.*
## Open Questions
*What this synthesis surfaces that the wiki doesn't yet have an answer for. Good candidates for future research.*
## Related
- [[<Concept A>]]
- [[<Concept B>]]
- [[<other related pages>]]
```
**Synthesis pages are mostly `^[inferred]`.** You are drawing connections across sources — that's synthesis by definition. Apply `^[inferred]` to cross-cutting conclusions and `^[ambiguous]` where sources disagree.
**The title format is `A × B`** — this signals to readers that it's a synthesis page, not a page about either concept alone.
## Step 5: Back-link from Source Pages
For each synthesis page you created, add a link to it from the two (or more) concept pages it synthesizes. In the concept page, add to its `## Related` section:
```markdown
- [[Concept A × Concept B]] — synthesis
```
If the concept page has no `## Related` section, add one at the bottom.
## Step 6: Report Synthesis Opportunities Not Taken
After creating pages for the top 5, list the next 10 candidates in your output — pairs that scored well but you didn't write pages for. This gives the user visibility into what the wiki thinks is worth exploring without forcing every synthesis in one run.
Format:
```
Skipped (consider next time):
- [[Caching]] × [[Consistency]] — co-occurs in 4 pages, cross-domain
- [[Testing]] × [[Observability]] — co-occurs in 3 pages, shares tags
...
```
## Step 7: Update Special Files
One locked call updates the index, the log, and the hot cache:
```bash
obsidian-wiki memory sync WIKI_SYNTHESIZE \
pages_scanned=<N> synthesis_created=<M> candidates_skipped=<K> \
--takeaways "Synthesized 5 cross-cutting pages: Caching × Consistency, Testing × Observability, …"
```
Open questions the synthesis surfaced are threads, not takeaways — record each one:
`obsidian-wiki memory todo add "<question>" --origin synthesis/<page>.md`.
Never hand-edit `index.md`, `log.md`, or `hot.md` — the command takes the lock that keeps a parallel writer from dropping your update.
See `.skills/llm-wiki/references/MEMORY.md` for the full procedure.
## Quality Checklist
- [ ] Every synthesis page has a `summary:` field (≤200 chars)
- [ ] Every synthesis page links back to its source concepts
- [ ] Source concept pages link forward to the synthesis page
- [ ] No synthesis page just restates what's already on the source pages — it must add a cross-cutting insight
- [ ] Every synthesis page names its Strongest Objection with a testable search query (not an invented source)
- [ ] `index.md` and `log.md` updated
- [ ] `hot.md` updated
## Tips
- **A synthesis page that only summarizes its sources is useless.** The value is the connection — the thing neither source page says explicitly.
- **Don't synthesize for synthesis's sake.** If two concepts just happen to appear together a lot without a real conceptual link, skip them.
- **Three-way syntheses are powerful but rare.** Only create them when three concepts form a genuine triangle of mutual influence — not just because all three appear in the same project page.
- **Check `_insights.md` first.** The wiki-status skill may have already flagged synthesis candidates there — start with those before running the co-occurrence scan from scratch.
## QMD Refresh After Vault Writes
QMD is a search index, not the source of truth. If `$QMD_WIKI_COLLECTION` is empty or unset, skip this step. Run it only after this skill has written or rewritten vault markdown. If QMD refresh fails, do not roll back the vault changes; report the QMD status separately.
Use `$QMD_CLI` if set; otherwise use `qmd`.
```bash
${QMD_CLI:-qmd} update
```
If the output says vectors are needed or embeddings may be stale, run:
```bash
${QMD_CLI:-qmd} embed
```
Verify the collection with either:
```bash
${QMD_CLI:-qmd} ls "$QMD_WIKI_COLLECTION"
```
or, when a specific page path is known:
```bash
${QMD_CLI:-qmd} get "qmd://$QMD_WIKI_COLLECTION/<page>.md" -l 5
```
Record one of:
- `QMD refreshed: update + embed + verified`
- `QMD refreshed: update only + verified`
- `QMD skipped: QMD_WIKI_COLLECTION unset`
- `QMD skipped: qmd CLI unavailable`
- `QMD failed: <short error summary>`
© Ar9av · MIT · Ar9av/obsidian-wiki