Agent skill

Hipocampus Search

by kevin-hs-sohn in kevin-hs-sohn/hipocampus

Search memory using qmd (BM25 + optional vector) and compaction tree traversal.

MITAuto-check passedAI & LLM Engineering

Install Hipocampus Search

skills CLI

$ npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install kevin-hs-sohn/hipocampus hipocampus-search --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/kevin-hs-sohn/hipocampus.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/search .claude/skills/hipocampus-search && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "hipocampus-search" agent skill from https://github.com/kevin-hs-sohn/hipocampus/tree/main/skills/search into .claude/skills/hipocampus-search/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hipocampus-search", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/kevin-hs-sohn/hipocampus/tree/main/skills/search

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install kevin-hs-sohn/hipocampus hipocampus-search --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/kevin-hs-sohn/hipocampus.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/search .agents/skills/hipocampus-search && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "hipocampus-search" agent skill from https://github.com/kevin-hs-sohn/hipocampus/tree/main/skills/search into .agents/skills/hipocampus-search/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hipocampus-search", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install kevin-hs-sohn/hipocampus hipocampus-search --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/kevin-hs-sohn/hipocampus.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/search .cursor/skills/hipocampus-search && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "hipocampus-search" agent skill from https://github.com/kevin-hs-sohn/hipocampus/tree/main/skills/search into .cursor/skills/hipocampus-search/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hipocampus-search", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/kevin-hs-sohn/hipocampus.git --path skills/search

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install kevin-hs-sohn/hipocampus hipocampus-search --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/kevin-hs-sohn/hipocampus.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/search .gemini/skills/hipocampus-search && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "hipocampus-search" agent skill from https://github.com/kevin-hs-sohn/hipocampus/tree/main/skills/search into .gemini/skills/hipocampus-search/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hipocampus-search", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install kevin-hs-sohn/hipocampus hipocampus-search

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/kevin-hs-sohn/hipocampus.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/search .github/skills/hipocampus-search && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "hipocampus-search" agent skill from https://github.com/kevin-hs-sohn/hipocampus/tree/main/skills/search into .github/skills/hipocampus-search/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hipocampus-search", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install kevin-hs-sohn/hipocampus hipocampus-search --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/kevin-hs-sohn/hipocampus.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/search .opencode/skills/hipocampus-search && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "hipocampus-search" agent skill from https://github.com/kevin-hs-sohn/hipocampus/tree/main/skills/search into .opencode/skills/hipocampus-search/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "hipocampus-search", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: hipocampus-search
GitHub stars: 210
Token cost: ~956 tokens
SKILL.md length: 437 words
Files: 1
Skills in repo: 8
Repo updated: Jun 8, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Search memory using qmd (BM25 + optional vector) and compaction tree traversal.

Works in 3 steps: Use 2-4 specific keywords — more precise… → No natural language — strip filler words → Try variations — if first query misses,…
AI & LLM Engineering work in your project
SKILL.md covers Quick Reference, Which Search to Use, ROOT.md — "Do I Know About… and BM25 Query Construction, plus 4 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Hipocampus Search is an agent skill from kevin-hs-sohn/hipocampus. Search memory using qmd (BM25 + optional vector) and compaction tree traversal. Use ROOT.md to decide whether to search memory or look externally. Always check memory before external lookups.

Its SKILL.md is about 960 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in AI & LLM Engineering. The repository describes itself as: Drop-in memory harness for AI agents — 3-tier memory, compaction tree, hybrid search. One command to set up. Works with Claude Code and OpenClaw. The licence is MIT.

When your agent uses it

AI & LLM Engineering work in your project

Example prompts

“/hipocampus-search”

Workflow steps

3 steps, taken from the first numbered list in SKILL.md.

Use 2-4 specific keywords — more precise = better results
No natural language — strip filler words
Try variations — if first query misses, use synonyms or related terms

What it can do on your machine

Read from SKILL.md and the folder at commit df88ca1. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are bash).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Hipocampus Search loads about 956 tokens when it runs. Until then it costs about 52 tokens; SKILL.md has 437 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~52
When it runs · the whole SKILL.md, loaded when a task matches: ~956

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from kevin-hs-sohn/hipocampus at commit df88ca1, republished under its MIT licence (© kevin-hs-sohn). 437 words, ~956 tokens.

Download SKILL.mdSave it as .claude/skills/hipocampus-search/SKILL.md (or your agent's skills folder).

name: hipocampus-search
description: Search memory using qmd (BM25 + optional vector) and compaction tree traversal. Use ROOT.md to decide whether to search memory or look externally. Always check memory before external lookups.

Hipocampus Search

Quick Reference

Action	Command
Hybrid search (best quality)	`qmd query "keyword1 keyword2"`
Keyword search (fast)	`qmd search "keyword1 keyword2"`
Vector search only	`qmd vsearch "semantic query"`
Find files	`qmd search "query" --files`
Read file	`qmd get "path/to/file.md"`
Re-index	`qmd update`

Which Search to Use

Check hipocampus.config.json:

search.vector: true (default) → qmd query for best results (BM25 + vector + rerank)
search.vector: false → qmd search for BM25 keyword search

ROOT.md — "Do I Know About This?"

memory/ROOT.md is a functional index of everything in memory, auto-loaded every session. It has four sections:

Active Context — current week's work and priorities (immediate situational awareness)
Recent Patterns — cross-cutting insights not tied to a specific time period
Historical Summary — high-level chronology of past periods
Topics Index — keyword lookup table for O(1) "do I know about X?" judgment

Before any lookup, check ROOT.md first:

Topic found in Topics Index → search memory (qmd or tree traversal)
Topic NOT in Topics Index → use external search or answer from general knowledge
This eliminates "loading to decide whether to load" — ROOT.md is always in context

This is the core value of the compaction tree. Search only works when you know what to search for. The Topics Index tells you what you know at a glance.

BM25 Query Construction

When using qmd search (BM25 mode), queries must be keywords, not natural language.

Rules

Use 2-4 specific keywords — more precise = better results
No natural language — strip filler words
Try variations — if first query misses, use synonyms or related terms

Examples

Bad (natural language)	Good (keywords)
"How do I configure the database?"	"database config"
"What did we decide about caching?"	"caching decision"

Show full SKILL.md (167 more words)Show less

Tree Traversal

When qmd search returns insufficient results, traverse the compaction tree:

1. ROOT.md Topics Index → confirm topic exists, note any file references
2. ROOT.md Historical Summary → identify relevant time period
3. memory/monthly/YYYY-MM.md → identify relevant week
4. memory/weekly/YYYY-WNN.md → identify relevant day
5. memory/daily/YYYY-MM-DD.md → detailed view
6. memory/YYYY-MM-DD.md → full raw original

Always try qmd search first. Tree traversal is the fallback.

When to Search

Before any external lookup — check ROOT.md, then search memory
Resuming prior work — search for task context, past progress
Past decisions — search daily logs and knowledge files
Credentials/configs — search before asking user

Without qmd

If qmd is not installed (e.g., --no-search was used during init, or the user has a different RAG tool), the memory system still works:

ROOT.md is always available — use the Topics Index for "do I know about this?" judgment
Tree traversal works without qmd — just read the files directly: ROOT → monthly/ → weekly/ → daily/ → raw
Manual file reads — use ls memory/daily/ to find files, then read them
Skip qmd update / qmd search commands — they will fail silently

The compaction tree and checkpoint protocol are fully independent of qmd. Search is a convenience layer, not a requirement.

After Modifying Files

If qmd is installed, re-index after changing memory or knowledge files:

bash

qmd update

Files

Just SKILL.md in skills/search of kevin-hs-sohn/hipocampus.

Open the folder on GitHubat commit df88ca1

Compare with similar skills

Hipocampus Search next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Hipocampus Search compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Hipocampus Search this skillkevin-hs-sohn/hipocampus	210	—	~956	Automated safety check: Pass	MIT	4 mo ago
Agent BuildershareAI-lab/learn-claude-code	78k	4 repos	~1.2k	Automated safety check: Pass	MIT	12 days ago
Planning With Filesjarrodwatts/claude-code-config	1.1k	5 repos	~967	Automated safety check: Pass	None	8 mo ago
Codebase Managementgiancarloerra/SocratiCode	3.3k	1 repos	~1.8k	Automated safety check: Pass	AGPL-3.0	today
Context Compressionguanyang/open-agent-hub	977	2 repos	~4.6k	Automated safety check: Pass	MIT	today
Looperksimback/looper	710	—	~2.7k	Automated safety check: Notes	MIT	2 mo ago

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Questions about Hipocampus Search

What does Hipocampus Search do?

Search memory using qmd (BM25 + optional vector) and compaction tree traversal. Hipocampus Search is an agent skill from kevin-hs-sohn/hipocampus. Search memory using qmd (BM25 + optional vector) and compaction tree traversal.

When should I use Hipocampus Search?

Hipocampus Search fits situations like: AI & LLM Engineering work in your project.

How do I install Hipocampus Search in Claude Code?

Run `npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a claude-code`. Or copy the skill folder (skills/search in kevin-hs-sohn/hipocampus) into .claude/skills/hipocampus-search in your project. Claude Code loads it when a task matches its description.

How do I install Hipocampus Search in Codex?

Run `npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a codex`. Or copy the skill folder (skills/search in kevin-hs-sohn/hipocampus) into .agents/skills/hipocampus-search in your project. Codex loads it when a task matches its description.

Can I use Hipocampus Search in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add kevin-hs-sohn/hipocampus --skill hipocampus-search -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/hipocampus-search, .gemini/skills/hipocampus-search, .github/skills/hipocampus-search and .opencode/skills/hipocampus-search in your project.

What does Hipocampus Search need to run?

SKILL.md names no scripts, command-line tools or credentials: Hipocampus Search is instructions for the agent only.

Does Hipocampus Search access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Hipocampus Search safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Hipocampus Search use?

Hipocampus Search is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Hipocampus Search use?

About 956 tokens (SKILL.md is roughly 3.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Hipocampus Search?

Skills that share tags, products or a category with Hipocampus Search: Agent Builder (shareAI-lab/learn-claude-code, 78k stars), Planning With Files (jarrodwatts/claude-code-config, 1.1k stars), Codebase Management (giancarloerra/SocratiCode, 3.3k stars) and Context Compression (guanyang/open-agent-hub, 977 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Hipocampus Search?

kevin-hs-sohn (a GitHub user) maintains it in kevin-hs-sohn/hipocampus, which has 210 GitHub stars. The repository holds 8 skills in this directory. The repository was last updated on June 8, 2026.

Source: kevin-hs-sohn/hipocampus on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Hipocampus Search

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Hipocampus Search

Quick Reference

Which Search to Use

ROOT.md — "Do I Know About This?"

BM25 Query Construction

Rules

Examples

Tree Traversal

When to Search

Without qmd

After Modifying Files

Files

Compare with similar skills

Similar skills

More from kevin-hs-sohn/hipocampus

Related

Questions about Hipocampus Search