Use Modellix LLM with CrewAI

Use CrewAI against the Modellix LLM gateway. Pass an OpenAI-compatible base_url of https://llm.modellix.ai/v1 to the built-in LLM class — you do not need a custom BaseLLM subclass for Modellix.

This page covers LLM text only (https://llm.modellix.ai).Modellix model IDs are provider/name (for example openai/gpt-5.5). Set that full string as model. See Models & Pricing.Custom LLM (BaseLLM) is for non-OpenAI protocols or special auth. Prefer the LLM + base_url path below for Modellix.

Set Up CrewAI

Install CrewAI

pip install "crewai[openai]"

Or with uv:

uv add "crewai[openai]"

The [openai] extra covers the native OpenAI-compatible client path used with custom_openai=True.

Set Credentials

Create a Modellix API key in the console:

export OPENAI_API_KEY="mdlx-xxxxxxxx"
export OPENAI_BASE_URL="https://llm.modellix.ai/v1"
# Legacy alias also works:
# export OPENAI_API_BASE="https://llm.modellix.ai/v1"

Setting	Value
`api_key` / `OPENAI_API_KEY`	Modellix API Key
`base_url` / `OPENAI_BASE_URL`	`https://llm.modellix.ai/v1` (include `/v1`)
`model`	Exact Modellix Model ID (`provider/name`)

Use a Modellix key, not an OpenAI platform key. Do not point CrewAI at the media host (https://api.modellix.ai). Prefer setting base_url (or custom_openai=True with env vars) so traffic does not fall back to api.openai.com.

Create an LLM Pointed at Modellix

Recommended: construct LLM with an explicit base_url and custom_openai=True so CrewAI uses the native OpenAI SDK against your gateway:

from crewai import Agent, Crew, LLM, Task

llm = LLM(
    model="openai/gpt-5.5",
    api_key="mdlx-xxxxxxxx",  # or rely on OPENAI_API_KEY
    base_url="https://llm.modellix.ai/v1",
    custom_openai=True,
    temperature=0.7,
)

agent = Agent(
    role="Coding Assistant",
    goal="Help with concise coding tasks",
    backstory="You are a careful software engineer.",
    llm=llm,
)

task = Task(
    description="Introduce yourself in one sentence.",
    expected_output="A single short sentence",
    agent=agent,
)

crew = Crew(agents=[agent], tasks=[task])
result = crew.kickoff()
print(result)

Change model to any catalog ID (anthropic/claude-sonnet-5, google/gemini-3.6-flash, and so on). Traffic still uses Chat Completions on https://llm.modellix.ai/v1.

On some CrewAI versions, a leading openai/ routing prefix may be stripped before the request is sent. If openai/gpt-5.5 fails with model-not-found, confirm the upstream model field still includes openai/. Prefer custom_openai=True with an explicit base_url, and try a non-openai/ catalog ID (for example anthropic/claude-sonnet-5) to verify the gateway path first.

If OPENAI_BASE_URL / OPENAI_API_BASE is already set, you can omit base_url in code, but keep custom_openai=True for unknown / namespaced model IDs so CrewAI does not route to the default OpenAI host. For the native OpenAI SDK path, install crewai[openai].

Optional: Environment-Only Configuration

export OPENAI_API_KEY="mdlx-xxxxxxxx"
export OPENAI_BASE_URL="https://llm.modellix.ai/v1"
export OPENAI_MODEL_NAME="openai/gpt-5.5"

from crewai import Agent, LLM

llm = LLM(model="openai/gpt-5.5", custom_openai=True)
agent = Agent(
    role="Assistant",
    goal="Help users",
    backstory="A helpful assistant.",
    llm=llm,
)

CrewAI resolves the base URL from base_url, then api_base, then OPENAI_BASE_URL, then legacy OPENAI_API_BASE.

Optional: Multi-Agent Crew

Share one Modellix LLM across agents, or give each agent a different catalog ID on the same gateway:

primary = LLM(
    model="openai/gpt-5.5",
    base_url="https://llm.modellix.ai/v1",
    api_key="mdlx-xxxxxxxx",
    custom_openai=True,
)
fast = LLM(
    model="google/gemini-3.6-flash",
    base_url="https://llm.modellix.ai/v1",
    api_key="mdlx-xxxxxxxx",
    custom_openai=True,
)

researcher = Agent(
    role="Researcher",
    goal="Gather facts",
    backstory="You research carefully.",
    llm=primary,
)
writer = Agent(
    role="Writer",
    goal="Write concise summaries",
    backstory="You write clearly.",
    llm=fast,
)

Troubleshooting

Symptom	Check
Still hitting OpenAI	Set `base_url` and/or `custom_openai=True`; key is a Modellix key
401 Unauthorized	`api_key` / `OPENAI_API_KEY` is valid
Model not found / 404	`model` is a full ID like `openai/gpt-5.5`; if `openai/` was stripped, try another catalog prefix or inspect the outbound request
Wrong path	`base_url` is `https://llm.modellix.ai/v1` (include `/v1`)
Env vs constructor conflict	Prefer per-`LLM` `base_url` + `api_key` for multi-provider setups

CrewAI — Connect to any LLM — LLM, base_url, OpenAI-compatible setup
CrewAI — Custom LLM — BaseLLM for non-standard protocols
LiteLLM removal / custom_openai — native OpenAI-compatible routing
OpenAI SDK — same /v1 gateway without CrewAI
Models & Pricing — Model IDs and rates
LLM API guide — protocols and curl examples

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Use Modellix LLM with CrewAI

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