Shared Skills Registry MCP

Status: self-hosted alpha. Latest release: GitHub releases · PyPI: shared-skills-registry-mcp (prerelease — install with --pre).

One self-hosted registry for your AI-agent skills — served to every MCP-capable agent you run.

Open SSR is a runtime-neutral skill registry. Publish a skill bundle (SKILL.md plus its references, templates, and scripts) once, and any MCP client — Claude Code, Claude Desktop, Cursor, Windsurf, Hermes, or your own SDK — can discover it, inspect the exact files and SHA-256 checksums, and install it into a local skills directory with guardrails. Every tool call and every install lands in a human-readable audit trail.

It is one small Python service you run yourself:

• Runtime-neutral — skills are served over plain MCP, so they are not siloed inside one vendor's plugin marketplace or a single agent's profile directory.
• Self-hosted — a single pip install, no accounts, no hosted service, no lock-in; your skills stay on your machines.
• Trust-inspectable — checksum-bearing bundle retrieval, caller-local installs bounded to an explicitly configured directory, whole-bundle replacement so stale files never survive updates, and a JSONL audit log of every action.
• Honestly scoped — an alpha for loopback or controlled private networks, with a written threat model and known limitations instead of marketing claims.

Why this exists

Agent skills are becoming multi-file capabilities — prompts plus templates, scripts, references, and provenance. But they usually live in scattered local folders:

• one skill copy on a laptop;
• another inside a Claude Code project;
• another inside a Hermes profile;
• another pasted into a repo or chat thread;
• no clear version, source, owner, or install history.

That gets messy fast. Skills drift, agents miss updates, and humans lose track of what is actually installed where.

First-party marketplaces solve this for one runtime at a time. Open SSR solves the part they won't: a registry you host, that every MCP-capable agent can pull from, with an audit trail a human can read. Shared Skills Registry MCP gives those skills a home — the public, SSR-only extraction of a working private MCP server (see docs/PRIVATE-MCP-REFERENCE.md).

What it does

The first public slice is intentionally narrow:

1. Registry — stores public-safe skill metadata and bundle paths.
2. HTTP tools — exposes /tools/list_shared_skills, /tools/search_shared_skills, /tools/describe_shared_skill, /tools/retrieve_shared_skill, and /tools/install_shared_skill.
3. MCP access — exposes the same SSR operations to MCP-compatible agents through the packaged shared-skills-registry-stdio command.
4. Local install path — installs only into an explicitly configured local skills root, with path/frontmatter/checksum validation.
5. Audit trail — records every tool call and local install result to a JSONL activity log, readable via GET /audit/recent.
6. Control panel — a zero-build web UI at /ui for browsing/searching the registry, inspecting bundles and checksums, watching the activity timeline, and editing registry entries.

The core path is:

publish a skill → discover it over MCP → inspect/retrieve the bundle → install it locally

Included starter catalog

The default registry ships with a deliberately curated catalog rather than a dump of one private agent environment:

• 12 public seed skills: project-memory, website-copywriting, codebase-design, diagnosing-bugs, domain-modeling, prototype, tdd, triage, handoff, teach, writing-great-skills, and systematic-debugging.
• One Open SSR companion skill: shared-skills-registry-access, a runtime-neutral workflow for both orchestrators and consumer agents using their own SSR.
• One explicit example: demo-research-brief, labeled example-only and intended for smoke tests and tutorials.

The catalog intentionally contains no default Hermes skills. Imported bundles come from pinned public repositories and retain source/owner metadata. See docs/SEED-CATALOG.md and THIRD_PARTY_NOTICES.md.

Quickstart

[!IMPORTANT] Open SSR 0.1.x is a self-hosted alpha for loopback or controlled private networks. It has no TLS and only optional shared-token authentication (SSR_MCP_AUTH_TOKEN), and it is not safe for direct public Internet exposure. Read the Known Limitations and Threat Model before a cross-machine deployment.

Requires Python 3.11–3.14. CI tests the supported floor and ceiling on Linux.

Install and run (60 seconds)

From PyPI (prerelease, so pass the prerelease flag):

# pipx
pipx install --pip-args=--pre shared-skills-registry-mcp

# or uv
uv tool install --prerelease=allow shared-skills-registry-mcp

# or plain pip in a venv
pip install --pre shared-skills-registry-mcp

Then start the service — the wheel bundles the full 14-entry starter catalog and UI, so no checkout is needed:

shared-skills-registry-http

Or from source:

git clone https://github.com/cobibean/shared-skills-registry-mcp
cd shared-skills-registry-mcp
python -m venv .venv && . .venv/bin/activate
pip install -e .
shared-skills-registry-http

(Contributors: install with pip install -e '.[test]' and run pytest -q — see CONTRIBUTING.md.)

Either way, the launcher prints the control-panel URL at startup. Open http://127.0.0.1:8765/ui in a browser, or check from another shell:

curl -s http://127.0.0.1:8765/healthz

If port 8765 is already in use, pick another loopback port and use it consistently in the browser, curl commands, and SSR_MCP_URL:

SSR_MCP_PORT=18765 shared-skills-registry-http

Connect an MCP client

With the HTTP service running, point your agent at the packaged stdio adapter. For Claude Code:

mkdir -p ~/ssr-skills   # start with a scratch install root; review bundles before pointing at a real one
claude mcp add shared-skills-registry \
  --env SSR_MCP_URL=http://127.0.0.1:8765 \
  --env SSR_MCP_SKILLS_ROOT="$HOME/ssr-skills" \
  -- shared-skills-registry-stdio

For Claude Desktop, Cursor, Windsurf, Hermes, or a generic MCP SDK, see docs/MCP-CLIENT-CONFIG.md for copy-pasteable configs. All five tools (list, search, describe, retrieve, install) work the same over every client.

Optional (recommended for any cross-machine use): require a bearer token

shared-skills-registry-generate-token
# prints: SSR_MCP_AUTH_TOKEN=<random-token>

Set the same SSR_MCP_AUTH_TOKEN in the HTTP service environment and in every MCP adapter or client .env. With it set, the /tools/..., /registry/..., and /audit/... routes require Authorization: Bearer <token>; /healthz and the static UI stay open, and the UI's Token button stores the token in your browser's localStorage. The token is a single shared secret, not TLS: on an untrusted network it can be intercepted, so the loopback/private-network boundary still applies.

Control panel

The UI is a single static file (ui/index.html) served by the same FastAPI process — no Node toolchain, no build step, works offline, and respects prefers-color-scheme for light/dark.

It gives you:

• Registry — search/filter every entry (including drafts and deprecated ones), with a warning chip when an entry's docs_path does not resolve on the server.
• Skill detail — full metadata plus the retrieved bundle: file list, sizes, and SHA-256 checksums (click to copy, click a file to preview its content).
• Activity — the audit timeline, auto-refreshing, newest first.
• Registry editing — add, edit, deprecate, or delete entries. Edits are validated with the same rules as the registry loader and written atomically to shared_skills.yaml. Editing is metadata-only: it points at bundle files already on the server host and never uploads or executes anything.

The editing surface lives on separate /registry/... admin routes, not on the agent-facing /tools/... surface, and every edit is recorded in the audit log. Set SSR_MCP_AUTH_TOKEN to require a bearer token on the tool, admin, and audit routes (the UI's Token button stores it in this browser only); still keep the service on loopback or behind authenticated transport for any private-network deployment.

MCP usage

The installed MCP stdio entry point is:

shared-skills-registry-stdio

It talks to the HTTP service through SSR_MCP_URL and installs skills only beneath the adapter-configured SSR_MCP_SKILLS_ROOT. Model-supplied per-call root overrides are rejected by default. The repository-relative client/stdio_server.py remains as a compatibility shim.

Example environment:

export SSR_MCP_URL=http://127.0.0.1:8765
export SSR_MCP_SKILLS_ROOT=/tmp/ssr-demo-skills
export SSR_MCP_AUDIT_LOG=$PWD/data/ssr_audit.jsonl
shared-skills-registry-stdio

MCP tools exposed:

• list_shared_skills
• search_shared_skills
• describe_shared_skill
• retrieve_shared_skill
• install_shared_skill

For copy-pasteable client configs, see:

• docs/MCP-CLIENT-CONFIG.md
• examples/mcp-client-config/shared-skills-registry.mcp.json
• examples/mcp-client-config/hermes-add-shared-skills-registry.sh

Verify the actual MCP stdio path

With the HTTP service running, exercise the adapter through a generic MCP client session rather than only calling HTTP endpoints:

tmp="$(mktemp -d)"
python scripts/mcp_stdio_smoke.py \
  --url http://127.0.0.1:8765 \
  --skills-root "$tmp/skills" \
  --audit-log "$tmp/local-audit.jsonl"

The smoke initializes MCP, verifies the five-tool catalog, then lists, searches, describes, retrieves, and installs project-memory. It exits nonzero if protocol initialization, a tool call, the caller-local install, or the local audit record fails. Use a scratch directory unless you intentionally want to install into a real agent skill root.

Registry schema

The public schema is intentionally close to the working private SSR schema:

version: 1
skills:
  - name: demo-research-brief
    title: "Example: Demo Research Brief"
    summary: Example-only bundle for testing registry browsing, MCP retrieval, checksum verification, and scratch-directory installation.
    category: example
    owner: open-ssr
    source: shared-skills-registry-mcp-example
    docs_path: examples/skills/demo-research-brief/SKILL.md
    applicability: Use only as a tutorial or smoke-test bundle.
    lifecycle_status: active
    install_guidance: Install only into a configured scratch skills directory.
    tags:
      - example
      - demo
      - smoke-test

See:

• config/shared_skills.yaml
• registry.example.yaml
• examples/skills/demo-research-brief

Add your own skill

Bundled and user-added production skills share one canonical tree:

skills/
  your-skill/
    SKILL.md
    references/
    templates/
    scripts/
    assets/

Place the bundle under skills/<name>/, then add a matching entry to config/shared_skills.yaml with:

docs_path: skills/your-skill/SKILL.md

The control panel's registry editor can create or update that metadata entry after the files exist on the server host. There is no separate seed namespace: starter status is provenance/catalog information, not a different installation layout.

Bundle rules

A skill bundle is rooted at the directory containing SKILL.md.

Always included:

SKILL.md

Allowed support directories:

references/
templates/
scripts/
assets/

Every retrieved file includes:

• relative path;
• size in bytes;
• SHA-256 checksum;
• content.

Install validation checks:

• no absolute paths;
• no null bytes;
• no .. path escapes;
• only allowed support directories;
• SKILL.md is required;
• SKILL.md frontmatter must be valid YAML;
• frontmatter name must match the requested skill;
• checksums must match before writing;
• writes are atomic;
• destination must stay inside the configured local skills root.

Audit / activity log

The service attempts to append one JSON audit event after each handled HTTP tool call, and the stdio adapter records local install results when SSR_MCP_AUDIT_LOG is set. Malformed requests rejected before a handler and audit-write failures may leave no event. Records omit bundle content and redact common secret-like fields, but heuristic redaction can miss arbitrary sensitive prose.

• Default location: data/ssr_audit.jsonl (gitignored).
• Override with SSR_MCP_AUDIT_LOG=/path/to/audit.jsonl.
• Read recent events: curl -s http://127.0.0.1:8765/audit/recent.

Event shape:

{
  "created_at": "2026-07-08T18:00:00+00:00",
  "event_type": "tool_call",
  "tool_name": "retrieve_shared_skill",
  "arguments": {"name": "demo-research-brief", "include_bundle": true},
  "result_summary": {"skill": "demo-research-brief", "file_count": 2, "total_size_bytes": 620},
  "status": "ok",
  "error_class": null,
  "latency_ms": 3
}

Known limitations

Open SSR is deliberately a narrow self-hosted alpha:

• only optional shared-token authentication (SSR_MCP_AUTH_TOKEN); no authorization model, TLS, rate limiting, or multi-tenant isolation;
• not supported for direct public Internet exposure;
• SHA-256 checks bundle integrity but does not prove publisher identity or make a skill benign;
• installation does not execute content, but agents may later follow instructions or run scripts from an installed skill;
• no package signing, dependency resolution, uninstall/version-history command, or automatic upstream updates;
• registry edits and installs are atomic but assume one writer at a time;
• audit JSONL is operational visibility, not signed or tamper-evident forensic evidence;
• release-gated CI currently targets Linux only.

Read the complete docs/KNOWN-LIMITATIONS.md, docs/THREAT-MODEL.md, and SECURITY.md before deployment. Undisclosed vulnerabilities should be reported through GitHub private vulnerability reporting, not a public issue.

What this is not

This project is deliberately not a full agent fleet control plane.

It is not:

• fleet orchestration;
• A2A messaging;
• remote control of agents;
• a hosted marketplace;
• arbitrary code execution;
• a secret-bearing internal ops dashboard.

The registry can return a checked bundle. The local adapter decides whether and where to install it. That boundary is the product.

Current project layout

client/                         Compatibility shim for older repo-relative stdio configs
config/shared_skills.yaml        Starter registry: 12 seeds + companion + example
docs/assets/                     README UI screenshot/GIF assets
examples/mcp-client-config/      Copy-pasteable MCP client configs
examples/skills/                 Public-safe example skill bundles
skills/                         Canonical skill bundles: bundled starters and user-added skills
scripts/mcp_stdio_smoke.py       Standalone generic MCP protocol smoke
src/shared_skills_registry_mcp/  FastAPI app, settings, SSR core
  app.py                         SSR-only HTTP tools
  audit.py                       Narrow JSONL activity log
  config.py                      Local/private bind-safe settings
  registry_edit.py               Registry editing (UI-facing admin routes)
  shared_skills.py               Ported registry/retrieve/install logic
tests/                           SSR core, HTTP, guardrail, and real MCP stdio tests
ui/index.html                    Control panel (served at /ui, zero build step)
docs/                            Product, demo, security, and extraction reference docs

Reference

• docs/PRIVATE-MCP-REFERENCE.md explains the public-safe architecture extraction from the larger private MCP server.
• docs/DEMO-SCRIPT.md contains the truthful launch post, README GIF, and three-minute video outline.
• docs/SECURITY-BOUNDARY.md summarizes what the registry does and does not do.
• docs/THREAT-MODEL.md documents assets, actors, boundaries, implemented controls, residual risks, and safe deployment profiles.
• docs/KNOWN-LIMITATIONS.md lists current alpha constraints without marketing shorthand.
• SECURITY.md explains private vulnerability reporting and support expectations.
• CONTRIBUTING.md covers setup, real MCP and release-artifact verification, catalog rules, attribution, and pull-request expectations.
• docs/RELEASE-CHECKLIST.md gates version selection, artifact verification, publication, consumer smoke, and failure handling.
• docs/releases/v0.1.0a1.md contains the approved first-alpha release notes and security boundary.
• docs/releases/v0.1.0a2.md contains the second-alpha (first PyPI) release notes.
• docs/LAUNCH-POST.md contains the platform-ready launch post drafts and posting sequence.