JSON Mapping & Context MCP Servers

This repo hosts two small MCP servers that showcase schema-aware JSON exploration and live data retrieval:

• JSON Mapping Finder (json_mapping_server.py): Upload any JSON sample, flatten its schema, and use heuristic search (token overlap + fuzzy matching) to find paths for target field names. Great for accelerating ETL/API onboarding.

It is intentionally lightweight and fully HTTP-based for easy inspection with the MCP Inspector or Copilot Chat.

Highlights

• Schema-aware parsing: Flattens nested JSON, captures types/examples, and tracks depth.

• Heuristic mapping: Token overlap, substring checks, and fuzzy matching to suggest likely field paths.

• Plug-and-play MCP: Uses StreamableHTTPSessionManager for modern MCP HTTP transport.

• Portable: Pure Python, no external services beyond Open-Meteo.

Related MCP server: MCP JSON Navigator

Quick Start

Prereqs: Python 3.12+ and a virtual environment (.venv recommended).

python -m venv .venv
source .venv/bin/activate
pip install -r <(python - <<'PY'
import tomllib, sys
deps = tomllib.load(open("pyproject.toml","rb"))["project"]["dependencies"]
print("\n".join(deps))
PY)

Run the JSON Mapping Finder (port 3004)

.venv/bin/python json_mapping_server.py

Then inspect with:

npx -y @modelcontextprotocol/inspector http://localhost:3004

Exposed tools:

• upload_json_sample(json_data): load a JSON sample (e.g., sample_json.json) and build the schema index.

• list_schema(limit=200): view flattened paths with type + example values.

• search_fields(query, top_k=10): find likely paths for a single query.

• map_targets(targets, top_k=5): bulk mapping suggestions for multiple field names.

• clear_samples(): reset the index.

Sample Data

• sample_json.json: a non-medical, nested sample for testing the JSON Mapping Finder.

Configuration

If you want to wire these into Copilot Chat, add entries like:

{
  "mcpServers": {
    "json-mapping": { "url": "http://localhost:3004" }
  }
}

How it works (JSON Mapping Finder)

1. Indexing: Walks objects/arrays, records paths ($.foo.bar[*]), types, example values, and depth.

2. Scoring: Combines exact/substring boosts, Jaccard token overlap, and fuzzy ratio; lightly penalizes deep paths.

3. Suggestions: Returns top matches with scores so you can review/accept quickly.

Notes

• No API keys required.

• All code is ASCII-only and dependency-light.