fabro/docs/public/core-concepts/models.mdx

---
title: "Models"
description: "How Fabro routes tasks to LLM models and providers"
---

No single model is best at everything. Fabro lets you assign the right model to each workflow step — cheap, fast models for boilerplate, frontier models for hard reasoning, and a different provider for cross-critique so the reviewer brings fresh eyes. When a provider goes down, Fabro can fail over automatically.

<Frame>
  <img src="/images/ensemble-workflow.svg" alt="Ensemble workflow: fan out to Opus and Gemini Pro, merge, then synthesize" />
</Frame>

## Model catalog

| Model | Provider | Aliases | Context | Cost (in/out per Mtok) | Speed |
|---|---|---|---|---|---|
| `claude-opus-4-7` | anthropic | `opus`, `claude-opus` | 1M | $5.00 / $25.00 | 25 tok/s |
| `claude-opus-4-6` | anthropic | | 1M | $5.00 / $25.00 | 25 tok/s |
| `claude-sonnet-4-6` | anthropic | `sonnet`, `claude-sonnet` | 200K | $3.00 / $15.00 | 50 tok/s |
| `claude-sonnet-4-5` | anthropic | | 200K | $3.00 / $15.00 | 50 tok/s |
| `claude-haiku-4-5` | anthropic | `haiku`, `claude-haiku` | 200K | $0.80 / $4.00 | 100 tok/s |
| `gpt-5.2` | openai | `gpt5` | 1M | $1.80 / $14.00 | 65 tok/s |
| `gpt-5-mini` | openai | `gpt5-mini` | 1M | $0.20 / $2.00 | 70 tok/s |
| `gpt-5.2-codex` | openai | | 1M | $1.80 / $14.00 | 100 tok/s |
| `gpt-5.3-codex` | openai | `codex` | 1M | $1.80 / $14.00 | 100 tok/s |
| `gpt-5.3-codex-spark` | openai | `codex-spark` | 128K | n/a | 1000 tok/s |
| `gpt-5.4` | openai | `gpt54` | 1M | $2.50 / $15.00 | 70 tok/s |
| `gpt-5.5` | openai | `gpt55` | 1M | $5.00 / $30.00 | 70 tok/s |
| `gpt-5.5-pro` | openai | `gpt55-pro` | 1M | $30.00 / $180.00 | 20 tok/s |
| `gpt-5.4-mini` | openai | `gpt54-mini` | 400K | $0.75 / $4.50 | 140 tok/s |
| `gpt-5.4-pro` | openai | `gpt54-pro` | 1M | $30.00 / $180.00 | 20 tok/s |
| `gemini-3.1-pro-preview` | gemini | `gemini-pro` | 1M | $2.00 / $12.00 | 85 tok/s |
| `gemini-3.1-pro-preview-customtools` | gemini | `gemini-customtools` | 1M | $2.00 / $12.00 | 85 tok/s |
| `gemini-3-flash-preview` | gemini | `gemini-flash` | 1M | $0.50 / $3.00 | 150 tok/s |
| `gemini-3.1-flash-lite-preview` | gemini | `gemini-flash-lite` | 1M | $0.20 / $1.50 | 200 tok/s |
| `kimi-k2.5` | kimi | `kimi` | 262K | $0.60 / $3.00 | 50 tok/s |
| `glm-4.7` | zai | `glm`, `glm4` | 203K | $0.60 / $2.20 | 100 tok/s |
| `minimax-m2.5` | minimax | `minimax` | 197K | $0.30 / $1.20 | 45 tok/s |
| `mercury-2` | inception | `mercury` | 131K | $0.20 / $0.80 | 1000 tok/s |

Each provider requires its own API key set via environment variable or matching vault token (e.g. `ANTHROPIC_API_KEY`, `OPENAI_API_KEY`, `GEMINI_API_KEY`). See the [Quick Start](/getting-started/quick-start) for setup.

## Configuring providers and models

Fabro's catalog starts with the built-in providers and models, then merges any `[llm]` entries from settings. Provider and model IDs are strings, so a server or project can add an OpenAI-compatible provider without a Fabro release.

```toml title="settings.toml"
[llm.providers.proxy]
display_name = "Acme Gateway"
adapter = "openai_compatible"
base_url = "https://llm-gateway.example.com/v1"
aliases = ["gateway"]

[llm.providers.proxy.auth]
credentials = ["env:ACME_GATEWAY_API_KEY", "vault:ACME_GATEWAY_API_KEY"]

[llm.providers.proxy.extra_headers]
x-portkey-api-key = { env = "PORTKEY_API_KEY" }
x-portkey-config = { literal = "@bedrock-prod" }

[llm.models."team-code-large"]
provider = "proxy"
api_id = "provider-wire-model-name"
agent_profile = "anthropic"
display_name = "Team Code Large"
family = "team-code"
default = true
aliases = ["team-code"]
estimated_output_tps = 80

[llm.models."team-code-large".limits]
context_window = 200000
max_output = 32000

[llm.models."team-code-large".features]
tools = true
reasoning = true
reasoning_effort = "levels"
prompt_cache = true
effort = true

[llm.models."team-code-large".controls]
reasoning_effort = ["low", "medium", "high"]
speed = ["fast"]

[llm.models."team-code-large".costs]
input_cost_per_mtok = 1.50
output_cost_per_mtok = 8.00
cache_input_cost_per_mtok = 0.30

[llm.models."team-code-large".costs.speed.fast]
input_cost_per_mtok = 3.00
output_cost_per_mtok = 16.00
cache_input_cost_per_mtok = 0.60
```

For [LiteLLM](/integrations/litellm), Fabro ships a disabled provider entry. Enable it in settings and declare the models your proxy exposes:

```toml title="settings.toml"
[llm.providers.litellm]
enabled = true
base_url = "http://localhost:4000/v1"

[llm.models."litellm-gpt-5"]
provider = "litellm"
api_id = "gpt-5"
display_name = "LiteLLM GPT-5"
family = "litellm"
default = true

[llm.models."litellm-gpt-5".limits]
context_window = 128000
max_output = 8192

[llm.models."litellm-gpt-5".features]
tools = true
vision = false
reasoning = false
```

`api_id` is the model name sent to the provider API. Omit it when the Fabro model ID and provider model ID are the same.

Provider auth is declared in `[llm.providers.<id>.auth]` with ordered `env:<NAME>` or `vault:<NAME>` refs. The primary auth header defaults to `bearer`; override with `header = { custom = "Header-Name" }` for providers like Anthropic that use `x-api-key`. Omit the `[llm.providers.<id>.auth]` block entirely for providers that need no API key (e.g. Ollama). Custom headers for any provider — including providers that need only typed headers and no API-key auth — go in `extra_headers` as `{ env = "NAME" }`, `{ vault = "NAME" }`, or `{ literal = "value" }`.

Provider `agent_profile` defaults from `adapter` and controls profile-specific behavior such as project-memory filenames, CLI/ACP command selection, and native session routing. Valid values are `anthropic`, `openai`, and `gemini`; model-level values override provider-level values.

Provider `billing_policy` defaults from `adapter` and controls usage-cost estimation. Use `openai`, `anthropic`, `gemini`, or `none`.

<Note>
Provider fields in configuration, APIs, and model routing are provider ID strings. Built-in names like `anthropic`, `openai`, and `gemini` still work, but custom IDs like `proxy` work anywhere a provider ID is accepted.
</Note>

### Ollama

Fabro ships an Ollama provider definition that is disabled by default. Enable it in settings when you want Fabro to route through a local Ollama server:

```toml title="settings.toml"
[llm.providers.ollama]
enabled = true
```

Enabling the provider alone does not expose any models — until #267 adds auto-discovery, add explicit `[llm.models.<id>]` blocks for each Ollama model you have pulled locally. Ollama's OpenAI-compatible endpoint accepts any bearer token, so local users can set `OLLAMA_API_KEY=ollama`.

## Default models

When no model or provider is specified, Fabro checks configured provider credentials and chooses the first configured provider by catalog priority. If no provider credentials are configured, it uses the catalog's global default model. Each provider has a default model:

| Provider | Default model |
|---|---|
| `anthropic` | `claude-opus-4-7` |
| `openai` | `gpt-5.5` |
| `gemini` | `gemini-3.1-pro-preview` |
| `kimi` | `kimi-k2.5` |
| `zai` | `glm-4.7` |
| `minimax` | `minimax-m2.5` |
| `inception` | `mercury` |

## Using models in workflows

Assign models to workflow nodes using [model stylesheets](/workflows/stylesheets), which use a CSS-like syntax:

```dot title="example.fabro"
digraph Example {
    graph [
        model_stylesheet="
            *        { model: claude-haiku-4-5; }
            .coding  { model: claude-sonnet-4-5; reasoning_effort: high; }
            #review  { model: gemini-3.1-pro-preview; }
        "
    ]

    spec     [label="Write Spec"]
    implement [label="Implement", class="coding"]
    review   [label="Review"]
}
```

This routes the spec node to Haiku (the default), implementation to Sonnet, and review to Gemini Pro.

## Overriding the default model

Model stylesheets set per-node models inside the workflow graph, but you can also override the default model for an entire run. This is useful for quick experimentation or when you want to swap models without editing the Graphviz file.

### CLI flags

Pass `--model` and optionally `--provider` to `fabro run`:

```bash
fabro run docs/internal/demo/01-hello.fabro --model claude-opus-4-6
fabro run docs/internal/demo/04-pipeline.fabro --model gemini-3.1-pro-preview
```

These flags set the default model for all nodes that don't have an explicit model assigned via a stylesheet. The provider is automatically inferred from the model catalog — you only need `--provider` for models not in the catalog or to force a specific provider.

### Run config TOML

For repeatable runs, set the model in a run config file:

```toml title="run.toml"
_version = 1

[workflow]
graph = "implement.fabro"

[run]
goal = "Implement the feature"

[run.model]
name = "claude-sonnet-4-5"
fallbacks = ["gemini", "openai"]
```

Then launch with:

```bash
fabro run run.toml
```

The `fallbacks` array is optional. Each entry may be a bare provider token (like `"gemini"`), a bare model alias (like `"gpt-5.4"`), or a qualified `"provider/model"` reference. Fabro tries them in order when the primary provider is unavailable.

<Note>
The precedence order is: node-level stylesheet > run config TOML > CLI flags > server defaults. More specific settings always win.
</Note>

## CLI commands

### List models

View all available models, or filter by provider:

```bash
fabro model list
fabro model list --provider anthropic
fabro model list --query codex
```

### Test models

Verify that your API keys are working by sending a test prompt to each configured provider:

```bash
fabro model test
fabro model test --model claude-sonnet-4-5
fabro model test --provider openai
```

This is useful for confirming connectivity after setup or when adding a new provider key.