2026-06-12 16:42:05 +00:00
---
description: Write evergreen knowledge to the SecondBrain vault with correct frontmatter and scope
---
Use this skill when you have knowledge that should persist across projects and sessions.
## Evergreen vs. ephemeral test
**Write to vault if:** the knowledge is reusable across projects (tool/API behavior, client-specific facts, conventions, cross-project patterns). Vault is for knowledge that survives the current session.
**Do NOT write to vault:** project-ephemeral state (current task, in-progress decisions, temporary context). These belong in project files or the episodic layer (session journal — handled automatically by SessionEnd hook).
os-vault: WS2 write-behavior eval harness + untuned baseline grid
plugins/os-vault/eval/ — held-out unprompted vault-write discrimination eval:
ambiguity ladder L1 explicit -> L3 conceptual, paired positives/negatives,
6 run-set scenarios on a new reportgen Ruby fixture + 6 frozen reserve twins,
isolated sandbox vault, headless-only runner, deterministic-first Ruby checker
(narrow judge fallback stubbable via OS_VAULT_EVAL_JUDGE_CMD), model-free
self-test 21/21. Scenario Task blocks are held-out; reserve never read.
Isolation seam: OS_VAULT_PATH overrides vault_path via config.load_config();
OS_VAULT_SKIP_REBUILD suppresses the SessionStart graphify rebuild. Write
SKILL.md contract fix (defers to vault-conventions.md) + Vault location section.
Baseline grid (run-set x sonnet/haiku x 3 reps + 1 counted canary, 37 reps):
positives 1/19, negatives 18/18. L1 persists every rep but routes to built-in
auto-memory instead of the vault; L2/L3 mostly don't persist; zero
over-triggering. Wording loop (step 4, not started) targets: trigger at
L2/L3, route to vault at L1. Loop-input candidates: vault note
os-vault-write-eval-baseline-grid-results. CLAUDE.md pointers updated for
this and os-status.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 16:46:22 +00:00
## Vault location
2026-06-12 16:42:05 +00:00
os-vault: WS2 write-behavior eval harness + untuned baseline grid
plugins/os-vault/eval/ — held-out unprompted vault-write discrimination eval:
ambiguity ladder L1 explicit -> L3 conceptual, paired positives/negatives,
6 run-set scenarios on a new reportgen Ruby fixture + 6 frozen reserve twins,
isolated sandbox vault, headless-only runner, deterministic-first Ruby checker
(narrow judge fallback stubbable via OS_VAULT_EVAL_JUDGE_CMD), model-free
self-test 21/21. Scenario Task blocks are held-out; reserve never read.
Isolation seam: OS_VAULT_PATH overrides vault_path via config.load_config();
OS_VAULT_SKIP_REBUILD suppresses the SessionStart graphify rebuild. Write
SKILL.md contract fix (defers to vault-conventions.md) + Vault location section.
Baseline grid (run-set x sonnet/haiku x 3 reps + 1 counted canary, 37 reps):
positives 1/19, negatives 18/18. L1 persists every rep but routes to built-in
auto-memory instead of the vault; L2/L3 mostly don't persist; zero
over-triggering. Wording loop (step 4, not started) targets: trigger at
L2/L3, route to vault at L1. Loop-input candidates: vault note
os-vault-write-eval-baseline-grid-results. CLAUDE.md pointers updated for
this and os-status.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 16:46:22 +00:00
The vault root is `~/Documents/SecondBrain` — unless the environment variable `OS_VAULT_PATH`
is set, in which case use that path as the vault root instead (rare; tests and evals use it to
point at an isolated vault).
2026-06-12 16:42:05 +00:00
os-vault: WS2 write-behavior eval harness + untuned baseline grid
plugins/os-vault/eval/ — held-out unprompted vault-write discrimination eval:
ambiguity ladder L1 explicit -> L3 conceptual, paired positives/negatives,
6 run-set scenarios on a new reportgen Ruby fixture + 6 frozen reserve twins,
isolated sandbox vault, headless-only runner, deterministic-first Ruby checker
(narrow judge fallback stubbable via OS_VAULT_EVAL_JUDGE_CMD), model-free
self-test 21/21. Scenario Task blocks are held-out; reserve never read.
Isolation seam: OS_VAULT_PATH overrides vault_path via config.load_config();
OS_VAULT_SKIP_REBUILD suppresses the SessionStart graphify rebuild. Write
SKILL.md contract fix (defers to vault-conventions.md) + Vault location section.
Baseline grid (run-set x sonnet/haiku x 3 reps + 1 counted canary, 37 reps):
positives 1/19, negatives 18/18. L1 persists every rep but routes to built-in
auto-memory instead of the vault; L2/L3 mostly don't persist; zero
over-triggering. Wording loop (step 4, not started) targets: trigger at
L2/L3, route to vault at L1. Loop-input candidates: vault note
os-vault-write-eval-baseline-grid-results. CLAUDE.md pointers updated for
this and os-status.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 16:46:22 +00:00
## Frontmatter contract — read vault-conventions.md first
**Before writing any note, read `vault-conventions.md` at the vault root.** It is the
single source of truth for the frontmatter schema, note types, and tag taxonomy — do not rely
on a remembered or summarized version, and do not duplicate its schema here. This file will go
stale if the contract is ever reconciled again and this summary isn't updated with it.
Brief summary, correct as of the last time this skill was edited (verify against
vault-conventions.md, not this list, if anything looks off):
2026-06-12 16:42:05 +00:00
os-vault: WS2 write-behavior eval harness + untuned baseline grid
plugins/os-vault/eval/ — held-out unprompted vault-write discrimination eval:
ambiguity ladder L1 explicit -> L3 conceptual, paired positives/negatives,
6 run-set scenarios on a new reportgen Ruby fixture + 6 frozen reserve twins,
isolated sandbox vault, headless-only runner, deterministic-first Ruby checker
(narrow judge fallback stubbable via OS_VAULT_EVAL_JUDGE_CMD), model-free
self-test 21/21. Scenario Task blocks are held-out; reserve never read.
Isolation seam: OS_VAULT_PATH overrides vault_path via config.load_config();
OS_VAULT_SKIP_REBUILD suppresses the SessionStart graphify rebuild. Write
SKILL.md contract fix (defers to vault-conventions.md) + Vault location section.
Baseline grid (run-set x sonnet/haiku x 3 reps + 1 counted canary, 37 reps):
positives 1/19, negatives 18/18. L1 persists every rep but routes to built-in
auto-memory instead of the vault; L2/L3 mostly don't persist; zero
over-triggering. Wording loop (step 4, not started) targets: trigger at
L2/L3, route to vault at L1. Loop-input candidates: vault note
os-vault-write-eval-baseline-grid-results. CLAUDE.md pointers updated for
this and os-status.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 16:46:22 +00:00
- `scope` is a frontmatter **field** (`global`/`project`/`client`), not a tag.
- `type` is both a frontmatter field and a `type/<...>` tag (kept in sync); valid values are
listed in vault-conventions.md's Note Types table (e.g. `howto` , `reference` , `convention` ,
`eval-results` , `hub` , `adr` , `log` — the table is authoritative, this list is illustrative).
- Tags are flat and namespaced across six facets — `type/` , `client/` , `project/` , `domain/` ,
`tool/` , `convention/` . `type/` is required; at least one other facet tag is recommended so the
note routes to the right context.
- Filenames are slug-only lowercase-kebab-case (no date prefix).
- Write `summary` at creation time — it is the primary router hint for graph traversal and
memsearch. Never defer it.
2026-06-12 16:42:05 +00:00
os-vault: WS2 write-behavior eval harness + untuned baseline grid
plugins/os-vault/eval/ — held-out unprompted vault-write discrimination eval:
ambiguity ladder L1 explicit -> L3 conceptual, paired positives/negatives,
6 run-set scenarios on a new reportgen Ruby fixture + 6 frozen reserve twins,
isolated sandbox vault, headless-only runner, deterministic-first Ruby checker
(narrow judge fallback stubbable via OS_VAULT_EVAL_JUDGE_CMD), model-free
self-test 21/21. Scenario Task blocks are held-out; reserve never read.
Isolation seam: OS_VAULT_PATH overrides vault_path via config.load_config();
OS_VAULT_SKIP_REBUILD suppresses the SessionStart graphify rebuild. Write
SKILL.md contract fix (defers to vault-conventions.md) + Vault location section.
Baseline grid (run-set x sonnet/haiku x 3 reps + 1 counted canary, 37 reps):
positives 1/19, negatives 18/18. L1 persists every rep but routes to built-in
auto-memory instead of the vault; L2/L3 mostly don't persist; zero
over-triggering. Wording loop (step 4, not started) targets: trigger at
L2/L3, route to vault at L1. Loop-input candidates: vault note
os-vault-write-eval-baseline-grid-results. CLAUDE.md pointers updated for
this and os-status.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 16:46:22 +00:00
**Write `summary` now.** Deferring it breaks retrieval.
2026-06-12 16:42:05 +00:00
## Vault-not-repo rule
os-vault: WS2 write-behavior eval harness + untuned baseline grid
plugins/os-vault/eval/ — held-out unprompted vault-write discrimination eval:
ambiguity ladder L1 explicit -> L3 conceptual, paired positives/negatives,
6 run-set scenarios on a new reportgen Ruby fixture + 6 frozen reserve twins,
isolated sandbox vault, headless-only runner, deterministic-first Ruby checker
(narrow judge fallback stubbable via OS_VAULT_EVAL_JUDGE_CMD), model-free
self-test 21/21. Scenario Task blocks are held-out; reserve never read.
Isolation seam: OS_VAULT_PATH overrides vault_path via config.load_config();
OS_VAULT_SKIP_REBUILD suppresses the SessionStart graphify rebuild. Write
SKILL.md contract fix (defers to vault-conventions.md) + Vault location section.
Baseline grid (run-set x sonnet/haiku x 3 reps + 1 counted canary, 37 reps):
positives 1/19, negatives 18/18. L1 persists every rep but routes to built-in
auto-memory instead of the vault; L2/L3 mostly don't persist; zero
over-triggering. Wording loop (step 4, not started) targets: trigger at
L2/L3, route to vault at L1. Loop-input candidates: vault note
os-vault-write-eval-baseline-grid-results. CLAUDE.md pointers updated for
this and os-status.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-07 16:46:22 +00:00
Write ONLY to the vault root (see Vault location above). Never silently write to a project repository what belongs in the vault. If in doubt, write to the vault.
2026-06-12 16:42:05 +00:00
## PostToolUse hook is automatic
When you write or edit a `.md` file in the vault, the PostToolUse hook records the vault write and invalidates the rebuild stamp — the graph refreshes incrementally (via `graphify extract --update` ) at the next session start, not immediately. You do not need to run graphify manually.
