Modal

Run Kimi K3 through Modal’s OpenAI-compatible inference endpoints

Modal serves Kimi K3 through an OpenAI-compatible Shared API and through dedicated Auto Endpoints. Fabro ships a disabled modal provider entry for Kimi K3. Enable it after Modal gives you an endpoint URL.

Prerequisites

• A Modal account
• A Kimi K3 Shared API or Auto Endpoint
• A Modal proxy-token pair

Create or select an endpoint

Use the Kimi K3 Shared API from the Modal model library, or create a dedicated Auto Endpoint:

modal endpoint create --model moonshotai/Kimi-K3

Find the endpoint URL in the Modal dashboard or with modal endpoint list. Modal serves its OpenAI-compatible API under /v1.

Create a proxy token

Modal endpoints are authenticated with two headers. Create a proxy-token pair:

modal workspace proxy-tokens create

The command prints a token ID that starts with wk- and a secret that starts with ws-. Modal shows the secret only once, so save both values immediately.

If your Modal workspace uses RBAC, allow the token in the endpoint’s environment:

modal workspace proxy-tokens allow wk-... main

Enable the provider

Add the provider override to the settings file used by the Fabro server. Include /v1 in the endpoint URL and omit a trailing slash.

settings.toml

_version = 1

[llm.providers.modal]
enabled = true
base_url = "https://your-endpoint.modal.run/v1"

The endpoint URL is not built into Fabro because Modal assigns it to your Shared API or Auto Endpoint.

Configure credentials

Store both proxy-token values in the target Fabro server vault:

fabro secret set MODAL_TOKEN_ID wk-...
fabro secret set MODAL_TOKEN_SECRET ws-...

# For a non-default remote server:
fabro secret --server https://your-fabro.example set MODAL_TOKEN_ID wk-...
fabro secret --server https://your-fabro.example set MODAL_TOKEN_SECRET ws-...

fabro provider login --provider modal is not supported in this release because that command accepts one credential value. Use the two fabro secret set commands above.

Modal does not use a bearer API key for these endpoints. Fabro sends the vault values as Modal-Key and Modal-Secret headers and does not send an Authorization header.

Included model

Fabro model slug	Modal API ID	Context	Input / cached input / output	Estimated speed
kimi-k3	moonshotai/Kimi-K3	1M tokens	$3.00 /$0.30 / $15.00 per MTok	460 tok/s

The catalog marks Kimi K3 as supporting tools, vision, reasoning, and prompt caching. Modal’s model ID is case-sensitive.

Use Kimi K3

fabro model list --provider modal
fabro model test --provider modal --model kimi-k3
fabro run workflow.fabro --provider modal --model kimi-k3

When targeting a non-default remote server, pass the same --server value:

fabro model list --server https://your-fabro.example --provider modal
fabro model test --server https://your-fabro.example --provider modal --model kimi-k3

In workflow stylesheets:

workflow.fabro

digraph Example {
    graph [
        model_stylesheet="
            * { model: modal/kimi-k3; }
        "
    ]

    start [shape=Mdiamond, label="Start"]
    work  [label="Work", prompt="Use Kimi K3 through Modal."]
    exit  [shape=Msquare, label="Exit"]

    start -> work -> exit
}

Direct SDK environment credentials

The built-in Modal provider reads its two headers from the Fabro vault. EnvCredentialSource does not configure Modal automatically because Modal uses two headers instead of one API-key reference.

For direct SDK use, enable Modal and set its endpoint URL in the catalog:

settings.toml

[llm.providers.modal]
enabled = true
base_url = "https://your-endpoint.modal.run/v1"

Then read both environment variables explicitly and create a typed credential after constructing catalog from those settings:

use fabro_auth::ApiCredential;
use fabro_llm::client::Client;
use std::collections::HashMap;

let credential = ApiCredential::with_extra_headers(
    "modal",
    HashMap::from([
        ("Modal-Key".to_string(), std::env::var("MODAL_TOKEN_ID")?),
        (
            "Modal-Secret".to_string(),
            std::env::var("MODAL_TOKEN_SECRET")?,
        ),
    ]),
);
let client = Client::from_credentials(vec![credential], catalog).await?;

Costs

Fabro estimates Shared API costs from Modal’s published Kimi K3 prices. Completion and reasoning tokens use the output rate. Modal responses do not include an authoritative charge, so Fabro reports cost_source = "estimated".

Dedicated Auto Endpoints use Modal compute billing instead of the Shared API token prices. The Fabro estimate does not represent that compute bill.

Troubleshooting

“provider ‘modal’ uses openai_compatible adapter but does not configure base_url” — Add the Modal endpoint URL under [llm.providers.modal]. Include /v1.

Modal is not configured — Set both MODAL_TOKEN_ID and MODAL_TOKEN_SECRET in the target server vault. One value is not sufficient.

401 or 403 — Confirm that the token pair belongs to the correct Modal workspace and environment. If the workspace uses RBAC, allow the token in that environment.

404 — Confirm that the base URL is the endpoint URL followed by /v1, with no trailing slash.

Unknown model — The built-in API ID is exactly moonshotai/Kimi-K3. Run fabro model test --provider modal --model kimi-k3 to test the configured offering.

Further reading

Modal Kimi K3

Shared API prices, model specifications, and Auto Endpoint setup.

Modal endpoint authentication

Proxy-token headers and endpoint calling conventions.