Agent JSON Reliability

Deterministic JSON repair + JSON Schema validation for AI agents.
No LLM. Safe refusal on ambiguity.

STATUS=BETA 0.1.0 · GitHub · PyPI · Official MCP Registry

Problem: agents emit malformed JSON (fences, trailing commas, single quotes). This tool inspects, safely repairs, and schema-validates that text. No LLM. No invented values.

Machine catalog: https://agent-json-reliability.onrender.com/v1/catalog
Skill: https://agent-json-reliability.onrender.com/skill.md

Quick start

uvx agent-json-reliability

MCP client config (stdio, published package):

{
  "mcpServers": {
    "agent-json-reliability": {
      "command": "uvx",
      "args": ["agent-json-reliability"]
    }
  }
}

AI agents and software frequently emit malformed JSON: markdown fences, trailing commas, single quotes, True/False/None, and extra prose around one object.

Agent JSON Reliability is a deterministic pipeline for that failure mode:

1. inspect — diagnose whether the text is JSON and which failures are present

2. safe repair — apply only structural, unambiguous fixes

3. validate — optional JSON Schema check on the result

4. structured diagnostics — valid_original, repaired, valid_final, schema_valid, unsafe_or_ambiguous, changes, errors

This is not a generic jsonschema wrapper. Missing semantic values are never invented. Ambiguous input is refused.

Primary HTTP endpoint (local/self-hosted): POST /v1/json/reliable

MCP tools (same core functions): reliable_json, validate_json, repair_json, inspect_json

Related MCP server: json-sanity

Before / after (safe repair)

Malformed agent output:

{
  "text": "```json\n{\"name\":\"alice\",\"age\":30,}\n```"
}

Expected result (semantically equivalent valid JSON):

• valid_original=false

• repaired=true

• valid_final=true

• unsafe_or_ambiguous=false

• json → {"name":"alice","age":30}

If a schema is supplied and satisfied: schema_valid=true.

Safe refusal (ambiguous)

Truncated input such as {"user": is JSON-intended but not deterministically repairable without inventing keys or values.

Expected:

• HTTP 200 (documented safe response)

• valid_final=false

• unsafe_or_ambiguous=true or repaired=false

Do not treat a correct refusal as a product failure.

Run locally (no Hunter)

python -m pip install -r requirements.txt
python serve.py

Binds 127.0.0.1:8770 by default. Set PUBLIC_BASE_URL to an HTTPS origin only when you expose the process yourself. Do not commit a temporary tunnel hostname as the canonical URL.

Hosted API (x402)

Public origin: https://agent-json-reliability.onrender.com

Inspect / validate / repair / MCP stay free. POST /v1/json/reliable returns HTTP 402 until an x402 PAYMENT-SIGNATURE settles 3000 atomic USDC (0.003) on Base (eip155:8453) via PayAI.

curl -s -D - -o /tmp/ajr.json -X POST https://agent-json-reliability.onrender.com/v1/json/reliable \
  -H "content-type: application/json" \
  -d '{"text":"{'\''a'\'': 1}"}'
# Expect: HTTP/1.1 402  and a PAYMENT-REQUIRED header. Do not send a signature unless you intend to pay.

HTTP examples

See examples/curl.md, examples/python.py, examples/javascript.js.

Remote examples use https://agent-json-reliability.onrender.com. Local default is http://127.0.0.1:8770.

Share URLs (optional, unverified telemetry tags):

• /?source=github

• /?source=mcp-registry

• /?source=api-directory

MCP (stdio — durable)

Package transport does not depend on a temporary public URL. Prefer uvx (above). From a checkout:

{
  "mcpServers": {
    "agent-json-reliability": {
      "command": "python",
      "args": ["-m", "products.gateway.mcp_stdio"]
    }
  }
}

Remote HTTP MCP (POST /mcp) is for a running instance.

Machine discovery

• Hosted origin: https://agent-json-reliability.onrender.com

• GET /.well-known/agent-services.json

• GET /.well-known/agent.json

• GET /.well-known/x402

• GET /openapi.json

• GET /llms.txt · GET /llms-full.txt · GET /AGENTS.md · GET /sitemap.xml · GET /robots.txt

• POST /mcp JSON-RPC (tools/list, tools/call)

What this package does not include

No Hunter market database, no private reports, no Windows user paths, no collectors, no wallets in this package. Hosted /v1/json/reliable is x402-paid; local MCP and inspect/validate/repair are free.