Models

You address the gateway by alias, not by upstream vendor name. An alias is a stable identity that the gateway resolves to a concrete model at request time, so your code never changes when the upstream does.

codai — the one name to rememberCopy Anchor Link

model: "codai" is the primary identity. Today it routes to Anthropic's current Claude models (the Opus, Fable, Sonnet and Haiku families), with automatic failover between approved deployments when one is unavailable. The chain behind the name can change. The x-codai-routed-to response header tells you which model served every request, and the live routing distribution on codai.ro shows where production traffic actually went. Models from other providers are not in this route; address them by name (see direct upstream names). Pin codai-max (or codai-fable) when you want Fable 5.1 first.

codai is also the alias with the most protection built in:

• Prompt caching is always on. The X-Codai-Cache: 0 opt-out is ignored for codai* aliases (it is honoured on direct upstream names). Cache reads cost roughly a tenth of fresh input.
• Every request is metered in micro-USD against your key, including any sub-calls the gateway makes on your behalf.
• Effort is a dial you control. The raw API defaults to medium; the VS Code config ships high (max is one dial step away). See effort and thinking.

Public aliasesCopy Anchor Link

These appear in GET /v1/models for every key.

Workload aliasesCopy Anchor Link

Hidden from /v1/models listings but resolvable by any key that can address codai. They exist so IDE integrations can pin a role to a model without inventing their own names.

codai Max (preview)Copy Anchor Link

codai-max-n is an opt-in hard-task mode, separate from the codai-max pin. It is off unless the gateway operator enables it; while it is off the name is rejected like any unknown model (HTTP 400). It is never listed in /v1/models and is addressable by any key that can address codai.

For each request the gateway:

1. generates several candidate answers in parallel (4 by default, at most 8);
2. drops broken candidates and, when code can be executed in the sandbox, prefers the candidates whose code actually runs;
3. asks one judge to compare all remaining candidates at once and pick one, with a confidence score;
4. when the judge is unsure, re-asks a frontier model once and serves that answer. An execution-verified answer is never escalated.

Special-purpose aliasesCopy Anchor Link

Details and examples are on the embeddings, audio & realtime page.

Direct upstream namesCopy Anchor Link

You can bypass aliases and name a concrete model — claude-sonnet-5-5, gpt-6.1-sol, gemini-3.8-flash, grok-4.6 and so on — when your plan allows it. GET /v1/models returns exactly what your key may address, aliases and concrete models alike:

curl https://ai.codai.ro/v1/models -H "Authorization: Bearer $CODAI_API_KEY"

{
  "object": "list",
  "data": [
    {
      "id": "codai",
      "object": "model",
      "created": 0,
      "owned_by": "codai",
      "codai": {
        "kind": "alias",
        "type": "chat",
        "routesTo": ["claude-opus-5-5", "claude-fable-5-1", "claude-opus-5", "claude-sonnet-5-5", "claude-sonnet-5", "claude-haiku-5-5", "claude-haiku-4-5"],
        "capabilities": { "tools": true, "vision": true, "streaming": true, "maxInputTokens": 1000000, "maxOutputTokens": 128000 }
      }
    }
  ]
}

The codai object is a non-standard extension; OpenAI-compatible clients ignore it, IDEs read it to size their context indicators. owned_by is codai for aliases and codai-upstream for concrete models.

Public catalogCopy Anchor Link

GET /v1/public/models needs no key. It returns the curated list of models codai names publicly, filtered by what the gateway routes right now: a model that is dropped from routing disappears from the response within minutes. It also lists codai's own open-weight models, which run on your device and are never routed by the gateway. CORS is open (*) and responses are cacheable for an hour, so websites can read it directly.

curl https://ai.codai.ro/v1/public/models

{
  "object": "list",
  "updated": "2026-10-11T12:00:00.000Z",
  "live": true,
  "aliases": [
    { "id": "codai", "description": "The default. Routes each request across Anthropic's current Claude models by task tier: …", "routesTo": ["claude-opus-5-5", "claude-fable-5-1", "claude-sonnet-5-5", "claude-haiku-5-5"] },
    { "id": "codai-fast", "description": "…", "routesTo": ["claude-haiku-5-5", "claude-haiku-4-5"] }
  ],
  "data": [
    { "id": "claude-opus-5-5", "name": "Claude Opus 5.5", "provider": "Anthropic", "family": "Claude Opus", "via": ["Google Vertex AI", "Microsoft Azure AI Foundry"], "tier": "large", "kind": "chat", "released": "2026-09-22", "own": false, "highlight": true, "aliases": ["codai"] },
    { "id": "gpt-6.1-sol", "name": "GPT-6.1 Sol", "provider": "OpenAI", "family": "GPT-6", "via": ["Microsoft Azure AI Foundry"], "tier": "large", "kind": "chat", "own": false, "highlight": true, "aliases": [] },
    { "id": "codai-nano", "name": "codai-nano", "provider": "codai", "family": "codai-nano", "via": ["on-device"], "tier": "small", "kind": "chat", "own": true, "highlight": true, "aliases": [], "base": "google/gemma-4-E2B-it", "note": "Runs on your Android phone in the codai app (LiteRT-LM). …" }
  ]
}

Whether your key may call a model is decided by GET /v1/models, not by this list.

How resolution worksCopy Anchor Link

Each alias carries a chain of { provider, upstreamModel } entries. On every request the gateway walks the chain, skips adapters currently marked unhealthy, and dispatches to the first healthy one. The chain is data, refreshed from the registry every minute — adding or swapping an upstream changes no client code. Your key's allowlist (if the tier sets one) is applied to the resolved model, not the alias, so a tier that allows codai also allows codai-fast.

Effort and thinkingCopy Anchor Link

Reasoning depth is a dial, not a model. Set it per request in either of two equivalent ways:

curl https://ai.codai.ro/v1/chat/completions \
  -H "Authorization: Bearer $CODAI_API_KEY" \
  -H "Content-Type: application/json" \
  -H "X-Codai-Effort: high" \
  -d '{ "model": "codai", "messages": [{ "role": "user", "content": "Prove that √2 is irrational." }] }'

The header wins when both are present. When neither is set, the gateway uses medium. Tiers, from cheapest to most expensive:

You can also enable extended thinking directly: X-Codai-Thinking: 1 turns it on, X-Codai-Thinking-Budget: <tokens> sets the budget (default 16 384).

Continuation dampeningCopy Anchor Link

In an agent loop, most turns are the model consuming a tool result rather than starting a task. On those tool-continuation turns the gateway clamps any injected thinking budget to 4 096 tokens so a 30-step loop does not pay the full max bill 30 times. Fresh user turns keep the full budget.

If you need the full budget on every step — a long proof carried across tool calls, for instance — send X-Codai-Thinking-Pin: 1. The response header x-codai-effort-continuation-dampened: 1 tells you when the clamp fired.

What the response tells youCopy Anchor Link