SkillMesh

Stop stuffing hundreds of tools into your LLM prompt. Route to the right ones.

SkillMesh is a retrieval router for agent tool catalogs. Instead of loading every skill/tool into every prompt, it selects the best few cards for the query and injects only those.

Why Teams Adopt SkillMesh

• Keeps prompts small as your catalog grows (top-K instead of full dump)
• Improves tool selection quality on multi-domain tasks
• Cuts token cost per call by avoiding irrelevant tool context
• Works with Claude (MCP), Codex (skill bundle), and local CLI workflows
• Standardized OpenAI-style function schemas for tool expansion

The Problem

LLM agents break when you load every tool into the prompt. Token counts explode, accuracy drops, and cost scales linearly with your catalog size. Teams with 50+ skills end up with bloated system prompts that confuse the model and burn budget.

SkillMesh solves this with retrieval-based routing: given a user query, it selects only the top-K most relevant expert cards and injects them into the prompt — keeping context small, accurate, and cheap.

High-Value Use Cases

• Internal AI assistants with large tool/skill catalogs (50+ cards)
• Multi-step workflows crossing domains (data -> ML -> infra -> reporting)
• Teams using MCP where tool overload hurts selection quality
• Role-based execution flows (Data-Analyst, Financial-Analyst, AWS-Engineer)

SkillMesh vs Static Skill Docs

	Static SKILL.md only	SkillMesh routing
Prompt strategy	Load broad instructions every turn	Inject only relevant top-K cards
Scale behavior	Gets noisy as catalog grows	Remains focused with retrieval
Multi-domain tasks	Manual tool prompting	Query-driven cross-domain routing
Expansion	Add docs and hope model picks right one	Add cards + retrieval handles selection

Before vs After

	Without SkillMesh	With SkillMesh
Prompt tokens	~50,000+ (all tools loaded)	~3,000 (top-K only)
Tool selection	Model guesses from a huge list	BM25+Dense retrieval picks the best match
Cost per call	High (full catalog every time)	Low (only relevant cards)
Accuracy	Degrades as catalog grows	Stays consistent
Multi-domain tasks	Confusing for the model	Routed precisely (clean + train + deploy)

How It Works

User Query
    │
    ▼
┌─────────────────────┐
│  BM25 + Dense Index  │  ← Scores every card in your registry
└─────────┬───────────┘
          │
          ▼
┌─────────────────────┐
│   RRF Fusion Rank    │  ← Merges sparse + dense rankings
└─────────┬───────────┘
          │
          ▼
┌─────────────────────┐
│   Top-K Card Select  │  ← Returns the K best expert cards
└─────────┬───────────┘
          │
          ▼
┌─────────────────────┐
│  Agent acts as expert │  ← Full instructions injected into prompt
└─────────────────────┘

Each card contains: execution behavior, decision trees, anti-patterns, output contracts, and composability hints — everything the agent needs to act as a domain expert.

One-line MCP install (Claude Desktop / Claude Code)

Add this to your Claude Desktop config (claude_desktop_config.json) or Claude Code MCP settings:

{
  "mcpServers": {
    "skillmesh": {
      "command": "uvx",
      "args": ["--from", "skillmesh[mcp]", "skillmesh-mcp"]
    }
  }
}

No env vars. No file paths. No cloning. The bundled registry is included in the package.

Requires uv to be installed.

60-Second Demo

git clone https://github.com/varunreddy/SkillMesh.git
cd SkillMesh
pip install -e .
skillmesh emit \
  --provider claude \
  --registry examples/registry/tools.json \
  --query "clean messy sales data, train a baseline model, and generate charts" \
  --top-k 5

Output (truncated):

<context>
  <card id="data.data-cleaning" title="Data Cleaning and Validation Expert">
    # Data Cleaning and Validation Expert
    Specialist in detecting and correcting data quality issues...
  </card>
  <card id="ml.sklearn-modeling" title="Scikit-learn Modeling and Evaluation">
    ...
  </card>
  <card id="viz.matplotlib-seaborn" title="Visualization with Matplotlib and Seaborn">
    ...
  </card>
</context>

Only the relevant experts are injected — the rest of the 100+ card catalog stays out of the prompt.

Integrations

Platform	Method	Status	Docs
Claude Code	MCP server	Supported	Setup guide
Claude Desktop	MCP server	Supported	Setup guide
Codex	Skill bundle	Supported	Setup guide

Claude MCP Server

The easiest way to run it is via uvx (see "One-line MCP install" above). For local development:

pip install -e .[mcp]
skillmesh-mcp

The server auto-discovers the registry: env var SKILLMESH_REGISTRY → repo root → bundled registry.

Exposes five tools via MCP:

• route_with_skillmesh(query, top_k) — provider-formatted context block
• retrieve_skillmesh_cards(query, top_k) — structured JSON payload
• list_skillmesh_roles(catalog?, registry?) — full role list with installed status
• list_installed_skillmesh_roles(catalog?, registry?) — installed roles only
• install_skillmesh_role(role, catalog?, registry?, dry_run?) — install by id or friendly name (for example Data-Analyst)

Copy-ready config templates in examples/mcp/.

Codex Skill Bundle

$skill-installer install https://github.com/varunreddy/SkillMesh/tree/main/skills/skillmesh

Direct role commands in SkillMesh:

skillmesh roles
skillmesh roles list
skillmesh Data-Analyst install
skillmesh roles install Data-Analyst

Or via installed bundle wrapper:

~/.codex/skills/skillmesh/scripts/roles.sh
~/.codex/skills/skillmesh/scripts/roles.sh list
~/.codex/skills/skillmesh/scripts/roles.sh install --role-id role.data-engineer

Quickstart

Install

python -m venv .venv && source .venv/bin/activate
pip install -e .[dev]

Optional extras:

pip install -e .[dense]   # Dense reranking with sentence-transformers
pip install -e .[mcp]     # Claude MCP server

Retrieve top-K cards

skillmesh retrieve \
  --registry examples/registry/tools.json \
  --query "set up nginx reverse proxy with SSL" \
  --top-k 3

Emit provider-ready context

skillmesh emit \
  --provider claude \
  --registry examples/registry/tools.json \
  --query "deploy container to GCP Cloud Run" \
  --top-k 5

Role Quickstart

List available role cards:

skillmesh roles list --catalog examples/registry/tools.json

Install a role by friendly name (adds missing dependencies):

skillmesh roles install Data-Analyst \
  --catalog examples/registry/tools.json \
  --registry ~/.codex/skills/skillmesh/installed.registry.yaml

Dry-run an install to preview what will be added:

skillmesh roles install AWS-Engineer \
  --catalog examples/registry/tools.json \
  --registry ~/.codex/skills/skillmesh/installed.registry.yaml \
  --dry-run

MCP equivalent (tool call):

install_skillmesh_role(role="Data-Analyst", catalog="examples/registry/tools.json", dry_run=false)

Curated Registries

Use domain-specific registries for tighter routing:

Registry	Domain	Cards
tools.json / tools.yaml	Full catalog	154
ml-engineering.registry.yaml	ML training & evaluation	33
data-engineering.registry.yaml	Pipelines & data platforms	14
bi-analytics.registry.yaml	BI & dashboards	21
devops.registry.yaml	DevOps & infrastructure	18
web-apis.registry.yaml	API design & patterns	11
cloud-gcp.registry.yaml	Google Cloud Platform	13
cloud-bi.registry.yaml	Cloud BI	17
roles.registry.yaml	Role orchestrators	11

skillmesh emit \
  --provider claude \
  --registry examples/registry/devops.registry.yaml \
  --query "configure prometheus alerting and grafana dashboards" \
  --top-k 3

Benchmarking

Use the reproducible benchmark template:

• Benchmark template
• Human eval workflow

CLI Commands

Command	Description
skillmesh retrieve	Top-K retrieval payload (JSON)
skillmesh fetch	Alias for retrieve (supports free-text query shorthand)
skillmesh emit	Provider-formatted context block
skillmesh index	Index registry into Chroma for persistent retrieval
skillmesh roles wizard	Interactive role picker and installer
skillmesh roles list	List available role cards from a catalog
skillmesh roles install	Install role card + missing dependency cards into target registry
skillmesh role	Alias for roles
skillmesh-mcp	Stdio MCP server for Claude

skillmesh retrieve/MCP payloads include invocation in OpenAI function-tool format for every card.

skillmesh --help

Repository Layout

src/skill_registry_rag/
├── models.py          # Tool/role card models
├── registry.py        # Registry loading + validation
├── retriever.py       # BM25 + optional dense retrieval
├── adapters/          # Provider formatters (codex, claude)
└── cli.py             # skillmesh CLI

examples/registry/
├── tools.json         # Full tool catalog
├── tools.yaml         # YAML version of full catalog
├── instructions/      # Expert instruction files (90+)
├── roles/             # Role orchestrator files
└── *.registry.yaml    # Domain-specific registries

skills/skillmesh/      # Codex-installable skill

Contributing

See CONTRIBUTING.md for how to add expert cards, create registries, and submit PRs.

Troubleshooting

skillmesh: command not found

pip install -e .

Missing registry path

The CLI and MCP server auto-discover the registry. If auto-discovery fails, pass --registry or set:

export SKILLMESH_REGISTRY=/path/to/tools.json
# or pass --registry on every command

skillmesh-mcp fails to start

pip install -e .[mcp]

Codex does not detect new skill

Restart Codex after running $skill-installer.

Development

ruff check src tests
pytest

License

MIT — see LICENSE.

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