Routing

Standard mode

The MESH router picks an upstream based on the requested model (or router mode), provider health, and the requested privacy class. By default, every call is served at standard_route privacy unless you ask for a stronger class.

Fallback chains

Pass route: "fallback" with a primary model and ordered backup models list. MESH returns the selected model and full chain in the response routing field.

{
  "model": "mesh/claude-sonnet-4.5",
  "models": ["mesh/claude-opus-4.5", "mesh/llama-4-maverick"],
  "route": "fallback",
  "messages": [{ "role": "user", "content": "Summarize this document." }]
}

Fallback candidates are filtered to the privacy class actually being served — the router will never silently downgrade your class when a candidate can’t earn it. If no candidate can serve the requested class, the call returns privacy_class_unavailable_for_model.

Privacy classes

Pick the upstream privacy guarantee per call. See MESH privacy classes for the full taxonomy.

{
  "model": "auto",
  "privacy": {
    "class": "protected_provider_route"
  },
  "messages": [{ "role": "user", "content": "sensitive prompt" }]
}

Four classes are available: standard_route, protected_provider_route, private_gateway_route, confidential_runtime_route. The legacy mode: "standard" and mode: "mesh" aliases continue to work and map to standard_route and private_gateway_route respectively. To let the router pick the strongest class the requested model supports:

{ "privacy": { "bestAvailable": true } }

To allow a downgrade if the model can’t earn the requested class:

{
  "privacy": {
    "class": "protected_provider_route",
    "allowFallbackToLowerClass": true
  }
}

The actual class served is always in the response privacy.class field.

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Standard mode

Fallback chains

Privacy classes

​Standard mode

​Fallback chains

​Privacy classes

Standard mode

Fallback chains

Privacy classes