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Mistral AI RAG citation JSON‑LD schema mismatch on edge node

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Problem Description – Mistral AI RAG citation JSON‑LD schema mismatch on edge node

Edge deployments of Mistral AI’s Retrieval‑Augmented Generation (RAG) pipeline are failing to produce citations that conform to the required JSON‑LD schema. Downstream parsers – e.g., knowledge‑graph ingest services – reject the payload, leading to:

  • Runtime crashes in Kubernetes edge pods (e.g., jsonschema.exceptions.ValidationError: 'author' is a required property).
  • Intermittent JSONDecodeError when the citation is plain text.
  • Loss of source traceability for generated answers.

Typical log excerpt from an IoT gateway fleet:


[2024-07-12 14:03:27] ERROR [RAG] Citation generation failed: output does not conform to JSON‑LD schema (code 0xC3)
Traceback (most recent call last):
  File "/opt/mistral/rag.py", line 212, in _format_citation
    jsonschema.validate(citation, JSONLD_SCHEMA)
jsonschema.exceptions.ValidationError: Missing required property '@context' in citation object

Other observed errors include:

  • ValidationError: Missing required property '@type' in citation object
  • SchemaMismatchError: 'author' field type mismatch – expected object, got string
  • EdgeRuntimeError: Failed to serialize citation payload – TypeError: Object of type Citation is not JSON serializable

Root Cause Analysis

The RAG module selects a citation serialization format at runtime based on the citation_format parameter. On constrained edge nodes, the SDK defaults to a compact format to reduce payload size. This compact format omits the mandatory @context and @type fields defined in the Mistral AI JSON‑LD Schema Specification. The default behavior is documented in the RAG guide – citation output configuration, which states that the jsonld format must be explicitly requested when strict schema compliance is required.

Edge‑specific constraints (ARM architecture, quantized models) trigger the fallback to the compact format, as reported in the GitHub issue #342 and the issue #128. The SDK bug manifested after a model update that introduced a new default for citation_format, causing previously compliant deployments to break.

Investigation and Debugging

  1. Confirm the citation payload structure. Capture the raw output from generate_with_citations:

>>> response = client.generate_with_citations(prompt="Explain quantum tunneling")
>>> print(response.citations)
[
  "Source: https://example.com/quantum-tunneling",
  "Source: https://physics.org/tunneling"
]

Notice the array of plain strings – not JSON‑LD objects.

  1. Validate against the official schema. Use the schema validator provided in the SDK:

from mistral.sdk.schema import JSONLD_SCHEMA
import jsonschema

for cit in response.citations:
    try:
        jsonschema.validate(cit, JSONLD_SCHEMA)
    except jsonschema.exceptions.ValidationError as e:
        print("Schema error:", e.message)

Output:


Schema error: Missing required property '@context' in citation object
  1. Check SDK configuration on the edge node. Review the initialization code:

client = MistralClient(
    endpoint="http://localhost:8000",
    api_key=os.getenv("MISTRAL_API_KEY"),
    # No citation_format specified – defaults to 'compact' on edge
)
  1. Inspect the runtime flags. The edge deployment guide (Edge Deployment Guide) mentions the --enable‑compact‑citations flag, which is enabled by default in the Helm chart for resource‑constrained pods.

kubectl get pod rag-worker-0 -o yaml | grep enable-compact-citations
# output: enable-compact-citations: true

Resolution – Enforcing JSON‑LD citation format

The fix consists of three parts: SDK configuration, deployment manifest adjustment, and optional schema validation guard.

Step 1 – Update SDK call to request JSON‑LD format

Before:


response = client.generate_with_citations(prompt, max_tokens=256)

After adding the explicit format parameter:


response = client.generate_with_citations(
    prompt,
    max_tokens=256,
    citation_format='jsonld'   # forces full JSON‑LD output
)

Step 2 – Disable compact citation flag in the edge pod spec

Before (Helm values snippet):


rag:
  resources:
    limits:
      cpu: "500m"
  enableCompactCitations: true

After setting the flag to false:


rag:
  resources:
    limits:
      cpu: "500m"
  enableCompactCitations: false   # ensure JSON‑LD is emitted

Step 3 – Add a runtime guard (optional but recommended)

Insert a lightweight validation step after generation to catch regressions early:


def validate_citations(citations):
    for cit in citations:
        jsonschema.validate(cit, JSONLD_SCHEMA)

# usage
response = client.generate_with_citations(..., citation_format='jsonld')
validate_citations(response.citations)

Validation – Confirming schema compliance

Run the same validation script from the investigation phase. Expected output:


# No exception raised – all citations conform

Sample compliant citation object (as defined in the JSON‑LD Specification):


{
  "@context": "https://schema.org/",
  "@type": "CreativeWork",
  "author": {
    "@type": "Person",
    "name": "Dr. Alice Smith"
  },
  "datePublished": "2023-11-02",
  "url": "https://example.com/quantum-tunneling",
  "title": "Quantum Tunneling Explained"
}

Additionally, monitor the pod logs for the absence of the previous error code 0xC3.

Best Practices and Prevention

  • Explicitly set citation_format='jsonld' in all production SDK calls. Do not rely on defaults, especially on edge nodes.
  • Pin the SDK version. The regression was introduced in mistral-sdk v2.3.1. Use >=2.3.2 where the default is safe.
  • Include schema validation in CI. Add a unit test that feeds a representative prompt and asserts JSON‑LD compliance.
  • Configure Helm/manifest flags consistently. Keep enableCompactCitations false for any service that downstreams citations.
  • Monitor for schema‑related errors. Create an alert on log pattern \[RAG\] Citation generation failed with severity “warning”.

Related Topic Hub: LLM Systems Troubleshooting Hub

FAQ

  1. Why does the citation format change after enabling model quantization?
    Quantization reduces model size and triggers the edge runtime to switch to the compact citation serializer to save bandwidth. The serializer omits @context and @type, breaking the JSON‑LD contract.
  2. Can I keep enableCompactCitations true and still get valid JSON‑LD?
    No. The compact mode is mutually exclusive with the full JSON‑LD schema. The only safe configuration is to disable compact mode and request citation_format='jsonld' explicitly.
  3. How do I verify which citation format the SDK is currently using?
    Inspect the response metadata:

print(response.metadata['citation_format'])
# Expected output: 'jsonld' or 'compact'
  1. Is there a performance impact when using full JSON‑LD citations on ARM edge devices?
    The payload size increases by ~30‑40 % due to additional fields. In most cases the impact is negligible (< 5 ms per request) but should be measured for high‑throughput scenarios.
  2. What version of the SDK introduced the regression?
    The regression appeared in mistral-sdk 2.3.1. Upgrading to 2.3.2 or later resolves the default‑fallback bug.