json-mcp-server
Provides a local Model Context Protocol (MCP) server exposing JSON-RPC tools to read, write/update, query (JSONPath), validate, and get help about JSON files—primarily for use by LLM/MCP clients via stdin/stdout.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
MCP server communicates via stdin/stdout (no TLS/auth described). Security therefore depends on deployment controls (local/sandboxed execution, filesystem permissions, and limiting which file paths the agent can request). Write operations pose integrity risks; path arguments are a likely attack surface (e.g., path traversal) though specific mitigations are not documented. Dependency health is not verifiable from the provided content.
⚡ Reliability
Best When
Running locally (or in a tightly sandboxed environment) with an MCP-compatible client, where file paths are controlled and the LLM needs structured access to JSON on disk.
Avoid When
When you cannot control which file paths the agent can request, or when you require strong enterprise security guarantees (authZ/authN, audit, tenant isolation) that are not described here.
Use Cases
- • Letting an LLM browse and extract data from local JSON files (optionally via JSONPath).
- • LLM-assisted transformation of JSON documents using merge/append/replacement semantics.
- • Validating JSON files and returning diagnostics to the user/agent.
- • Paginated reading of large JSON files to support incremental inspection.
Not For
- • Exposing JSON file operations over the open internet without additional sandboxing/auth controls.
- • Use as a multi-tenant hosted service without a strong authorization model and filesystem isolation.
- • Use as a general database replacement for concurrent writes/transactions.
Interface
Authentication
No authentication/authorization model is described. Access appears to rely on the MCP client/channel and the host environment. This increases the importance of sandboxing and controlling allowed file paths.
Pricing
Pricing not described; distribution appears via Cargo and release binaries/scripts.
Agent Metadata
Known Gotchas
- ⚠ Potentially unrestricted filesystem access via file_path argument—agents may attempt path traversal or unintended files unless constrained by the client/runtime.
- ⚠ Write modes (replace/merge_shallow/merge_deep/append) could produce unexpected results if the agent supplies incorrectly structured data.
- ⚠ Large JSON handling relies on tool parameters (limit/offset/start_index) and JSONPath correctness; overly broad JSONPath queries may still produce large outputs.
Alternatives
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Scores are editorial opinions as of 2026-04-04.