embeddings-setup

A setup skill for enabling semantic search in Open Second Brain, a tool for searching a personal knowledge collection. It covers the embedding API key, vector-search extension, first indexing, and optional refreshes.

In plain words
What is it for?
Checking and enabling embeddings, vector indexing, semantic search, and periodic index refreshes.
Why use it?
It guides you through the extra setup needed for meaning-based search instead of keyword-only search. It checks which part is missing before suggesting the next step.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/itechmeat/open-second-brain/embeddings-setup
Any agent
npx skills add itechmeat/open-second-brain --skill embeddings-setup
Clone the repo
git clone --depth 1 https://github.com/itechmeat/open-second-brain

Made for: Claude Code, Codex.

Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,368 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00105 $0.01368
Opus 5 $0.00053 $0.00684
Sonnet 5 $0.00021 $0.00274
Haiku 4.5 $0.00011 $0.00137

Measured 2d ago against content hash 7efc472d7680, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

embeddings-setup scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/embeddings-setup/SKILL.md · 154 lines

How it starts

The opening of the file, as written. The whole thing — 154 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Embeddings setup

Open Second Brain ships with two search paths: keyword-only (always on, no credentials) and semantic via embedded vectors (opt-in). This SKILL walks the activation flow for the semantic path. The flow is proactive — when the user mentions semantic search or o2b search check surfaces missing pieces, take the user through this list rather than waiting for explicit instruction.

Step 1 — Always start with o2b search check

o2b search check

The output names every missing piece and ends with a recommendations: block listing the exact commands to fix each. Read both before suggesting next steps. The recommendations field is also present in the --json output for headless callers.

Branch on what the report shows:

  • embedding_key: MISSING → go to step 2.
  • vec_extension: unavailable on macOS → go to step 3.
  • vec_extension: unavailable on Linux → go to step 4.
  • Everything OK but semantic_enabled: false (no embeddings yet) → go to step 5.

Step 2 — Provider and API key

Ask the user which provider they want. The default is text-embedding-3-small from OpenAI (about $0.02 per 1M tokens, which covers tens of thousands of vault pages). Any OpenAI-compatible endpoint works — Groq, Together, a local LM Studio server, etc.

Required env vars (write to ~/.hermes/.env or the configured env file, never to a tracked file):

OPEN_SECOND_BRAIN_EMBEDDING_PROVIDER=openai-compat
OPEN_SECOND_BRAIN_EMBEDDING_MODEL=text-embedding-3-small
OPEN_SECOND_BRAIN_EMBEDDING_KEY=<placeholder; user pastes the key>
# Optional — only when not using OpenAI:
# OPEN_SECOND_BRAIN_EMBEDDING_BASE_URL=https://api.together.xyz/v1

Never invent or echo the key. Write a placeholder, then ask the user to paste their key in place of it. Recheck with o2b search check after the user confirms.

Step 3 — macOS: install Homebrew SQLite

Apple ships /usr/lib/libsqlite3.dylib with SQLITE_OMIT_LOAD_EXTENSION, so the optional sqlite-vec extension cannot load against the system SQLite. Homebrew's sqlite formula is built with extension loading enabled.

Read the full file on GitHub · 154 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 154 lines · 0 tokens per session scan A 7efc472d7680

Subscribe to this mod's changes

embeddings-setup is a skill published in the GitHub repository itechmeat/open-second-brain (385 stars, last pushed 5d ago), licensed MIT. It adds 105 tokens to every session and 1,368 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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