Coding Harnesses

Connect Claude Code, the Claude Agent SDK, OpenCode, Codex, Pi, Cursor IDE, VS Code, Copilot, or DeepSeek Harness to Fireworks, with FireConnect or by editing the harness settings yourself.

Every harness below works two ways. FireConnect writes the settings for you and restores them with off. Manual setup shows the same settings so you can apply them yourself, with no extra tool installed.

Claude Code

Messages API

Codex CLI, Codex app, and ChatGPT

Responses API

OpenCode

Chat Completions

Pi

Chat Completions

Cursor IDE

Chat Completions

VS Code

Chat Completions

Copilot App

Chat Completions

Copilot CLI

Chat Completions

DeepSeek Harness

Chat Completions

Before you start

FireConnect

Install FireConnect and sign in once:

fireconnect login

• Connect: fireconnect <harness>. Add --model <id> to choose a model or router. Browse IDs with fireconnect model list.
• Quit first: fully quit Cursor IDE, VS Code, and the Copilot App before connecting or running off. Restart other harnesses after connecting.
• Check: fireconnect <harness> status is read-only and safe while the app is open.
• Undo: fireconnect <harness> off restores the settings FireConnect saved under ~/.fireconnect/.

Manual setup

Create an API key in Fireworks settings and export it:

export FIREWORKS_API_KEY="fw_..."

Every harness uses the same Fireworks endpoints:

Harness API	Base URL
Anthropic Messages	https://api.fireworks.ai/inference
OpenAI Chat Completions or Responses	https://api.fireworks.ai/inference/v1

Use any model ID from Open Models, such as glm-latest, or a router from FireRouter, such as firerouter/opus. Back up a settings file before you edit it.

Claude Code

Anthropic Messages FireRouter Native web search

FireConnect

fireconnect claude
fireconnect claude status

Start a new session, or exit and run claude --resume <id>. FireConnect selects FireRouter by default. To choose another model, pass --model:

fireconnect claude --model glm-5p3-flash

--model sets the default model for new sessions. Anthropic tier slots stay native, and /model lists auto, the routers, and the Fireworks catalog.

~

.claude

settings.json

.claude.json

.fireconnect

See what FireConnect writes

~/.claude/settings.json

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.fireworks.ai/inference",
    "ANTHROPIC_CUSTOM_HEADERS": "X-Fireworks-Api-Key: fw_...",
    "DISABLE_TELEMETRY": "1",
    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1",
    "ENABLE_TOOL_SEARCH": "true"
  },
  "modelPicker": {
    "options": [
      { "model": "firerouter[1m]", "label": "FireRouter" },
      { "model": "auto[1m]", "label": "Auto" }
    ]
  },
  "model": "firerouter[1m]",
  "statusLine": { "type": "command", "command": "... claude-statusline.mjs" }
}

• The Fireworks key goes in a custom header, so your Claude login stays available for routes with Claude models.
• [1m] marks 1M-context models.
• The status line shows the estimated session cost. It is added only if you do not already have one.
• FireConnect also turns off Claude Code telemetry and nonessential traffic, and enables MCP tool search.
• ~/.claude.json records approval for the FireConnect credential so Claude Code does not prompt for it.

Manual setup

1. Point Claude Code at Fireworks

   Add these values to ~/.claude/settings.json:

   ~/.claude/settings.json

   {
     "env": {
       "ANTHROPIC_BASE_URL": "https://api.fireworks.ai/inference",
       "ANTHROPIC_AUTH_TOKEN": "fw_YOUR_FIREWORKS_API_KEY"
     },
     "model": "glm-latest"
   }
   

   Or set them for one shell:

   export ANTHROPIC_BASE_URL="https://api.fireworks.ai/inference"
   export ANTHROPIC_API_KEY="$FIREWORKS_API_KEY"
   claude --model glm-latest
   
2. Start a session

   Run claude. Claude Code may ask once whether to use the API key; approve it.

3. Optional: use FireRouter

   Set "model": "firerouter/opus". For Claude models in the route, connect an Anthropic Provider Key, or add x-anthropic-api-key to ANTHROPIC_CUSTOM_HEADERS.

Claude Code’s /model picker does not list Fireworks models you set by hand. Change models in settings.json or with claude --model <id>. Claude Code may log unrecognized_model for Fireworks IDs; requests still succeed.

Routers and credentials

• Bare firerouter and routes with Claude models can use your Claude login when you connect with FireConnect.
• firerouter/astra, firerouter/sol, and other GPT routes need an OpenAI key in Provider Keys with FireConnect, or an x-openai-api-key header in manual setup.
• See Routing Preferences for --routing-preference and Harness Compatibility for cross-harness support.

Usage and cost

For the status line and fireconnect claude usage, see Usage and Cost. Claude Code’s own in-app cost uses Anthropic list prices; use the FireConnect status line for the Fireworks estimate. For a side-by-side comparison, see the Side-by-Side Demo.

Troubleshooting

• Text-only models fail on pasted images. Use /rewind, or switch to a vision model such as glm-5p3-flash.
• Resume or restart the session after changing models.

Claude Agent SDK

Anthropic Messages

The Claude Agent SDK can reuse the Claude Code settings above. Connect Claude Code first, with FireConnect or manually:

fireconnect claude --model firerouter/opus

In the SDK query options, include settingSources: ["user"]. The SDK then reads the Fireworks endpoint, model, and credentials from ~/.claude/settings.json.

Claude Desktop is not supported. fireconnect claude does not configure Claude Desktop’s third-party inference provider.

Codex

OpenAI Responses FireRouter Native web search

The Codex CLI, the Codex app, and the ChatGPT desktop app share one config in ~/.codex/config.toml, so one setup covers all three. Quit the Codex app and the ChatGPT app before you change it so their model lists refresh.

MCP servers and plugins in the ChatGPT desktop app don’t work reliably while FireConnect is on. See Harness Compatibility.

FireConnect

fireconnect codex
fireconnect codex status

The default model is auto. To add FireRouter to the Codex and ChatGPT model pickers, run fireconnect codex --model firerouter. Exit Codex and run codex resume <id>, or start a new session.

Codex CLI after connecting with FireRouter enabled; Auto is selected

~/.codex

config.toml

fireworks-model-catalog.json

See what FireConnect writes

~/.codex/config.toml

model_provider = "fireworks-ai"
model_catalog_json = "~/.codex/fireworks-model-catalog.json"
model = "auto"

[model_providers.fireworks-ai]
name = "Fireworks"
base_url = "https://api.fireworks.ai/inference/v1"
wire_api = "responses"
experimental_bearer_token = "fw_..."
requires_openai_auth = false

FireConnect keeps your other TOML settings, saves the key with file mode 0600, and writes a model catalog so Codex knows each model’s context window and capabilities.

Manual setup

1. Add a Fireworks provider

   ~/.codex/config.toml

   model_provider = "fireworks-ai"
   model = "glm-latest"
   
   [model_providers.fireworks-ai]
   name = "Fireworks"
   base_url = "https://api.fireworks.ai/inference/v1"
   wire_api = "responses"
   env_key = "FIREWORKS_API_KEY"
   
2. Run Codex

   codex
   

   Codex answers from glm-latest.

Without a model catalog, Codex warns that it has no metadata for Fireworks models and uses fallback limits. FireConnect writes that catalog for you.

ChatGPT desktop with FireRouter selected

When you resume an old session, select the provider explicitly:

codex resume <id> -c model_provider="fireworks-ai"

MiniMax models don’t work on Codex. Codex may insert assistant messages between tool_calls and tool_results, which MiniMax templates reject. Use a Chat Completions harness such as OpenCode for MiniMax.

OpenCode

OpenAI Chat Completions FireRouter

FireConnect

fireconnect opencode
fireconnect opencode status

Restart OpenCode. The default model is auto, stored as fireworks-ai/auto. Short IDs such as glm-5p2 expand to full Fireworks paths.

OpenCode model picker after FireConnect, with Auto selected

See what FireConnect writes

~/.config/opencode/opencode.json

{
  "provider": {
    "fireworks-ai": {
      "options": { "apiKey": "fw_..." },
      "models": {
        "auto": { "name": "Auto", "limit": { "context": 1048575, "output": 131072 } },
        "glm-latest": { "name": "GLM (Latest)" }
      }
    }
  },
  "model": "fireworks-ai/auto"
}

The file is saved with mode 0600. FireConnect never changes auth.json. Use --config-path for a config stored elsewhere.

Manual setup

Fastest: in OpenCode, run /connect, search fireworks.ai, paste your key, and pick a model with /models.

Or edit the config to add routers and pin a default:

~/.config/opencode/opencode.json

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "fireworks-ai": {
      "options": { "apiKey": "{env:FIREWORKS_API_KEY}" },
      "models": {
        "glm-latest": { "name": "GLM (Latest)" },
        "firerouter/opus": { "name": "FireRouter Opus" }
      }
    }
  },
  "model": "fireworks-ai/glm-latest"
}

opencode run -m fireworks-ai/firerouter/opus "hello" answers through FireRouter.

Pi

OpenAI Chat Completions FireRouter

FireConnect

fireconnect pi
fireconnect pi status

Restart Pi if it was running. The default model is auto.

~/.pi/agent

settings.json

auth.json

models.json

See what FireConnect writes

~/.pi/agent/settings.json

{
  "defaultProvider": "fireworks",
  "defaultModel": "auto",
  "enabledModels": ["fireworks/accounts/fireworks/routers/*", "fireworks/auto"]
}

~/.pi/agent/auth.json

{ "fireworks": { "type": "api_key", "key": "fw_..." } }

models.json adds the Fireworks catalog to Pi’s built-in fireworks provider. FireConnect tracks the IDs it adds so off removes only those. Use --settings-path for a settings file stored elsewhere.

Manual setup

Pi has a built-in fireworks provider that reads FIREWORKS_API_KEY. Set it as the default:

~/.pi/agent/settings.json

{
  "defaultProvider": "fireworks",
  "defaultModel": "accounts/fireworks/routers/glm-latest"
}

pi -p "hello" answers from GLM.

Cursor IDE

OpenAI Chat Completions FireRouter with Provider Keys

fireconnect cursor configures Cursor IDE. Cursor CLI (agent or cursor-agent) is not supported. Fully quit Cursor IDE before connecting or running off.

FireConnect

fireconnect cursor
fireconnect cursor status

FireConnect points every existing mode in modelConfig at the Fireworks default and registers the catalog in the picker. Reopen Cursor IDE and choose a Fireworks model.

Cursor IDE after FireConnect, with Auto selected

See what FireConnect writes

Cursor IDE stores AI settings in SQLite (state.vscdb under ~/.config/Cursor, ~/Library/Application Support/Cursor, or %APPDATA%\Cursor):

Setting	Value
cursorAuth/openAIKey	Your Fireworks key
openAIBaseUrl	https://api.fireworks.ai/inference/v1
aiSettings.userAddedModels	The Fireworks catalog, tracked for a clean off
aiSettings.modelOverrideDisabled	Cursor’s built-in models, hidden while connected
aiSettings.modelConfig[<mode>]	The Fireworks model for each mode

Your previous auth state is saved under ~/.fireconnect/cursor/. Use --db-path for a non-default state.vscdb.

Manual setup

1. Open model settings

   In Cursor IDE, open Settings, then Models.

2. Add your Fireworks key

   Under API Keys, paste your Fireworks key into OpenAI API Key. Turn on Override OpenAI Base URL and enter https://api.fireworks.ai/inference/v1.

3. Add a model

   Add a custom model with a Fireworks ID, such as glm-latest, then select it in chat.

While connected, only Fireworks models work. Cursor IDE’s built-in models are hidden until you run off. Cursor IDE also enforces a server-side allowlist, so not every Fireworks model is selectable. Some features may still use Cursor’s own backend, depending on plan and version.

VS Code

OpenAI Chat Completions FireRouter

FireConnect adds a Fireworks provider to GitHub Copilot Chat’s custom endpoints. This requires Copilot Pro or Enterprise. Quit VS Code before connecting or running off.

FireConnect

fireconnect vscode
fireconnect vscode status

Restart VS Code, then pick a model under Other Models → Fireworks in Copilot Chat. glm-latest and glm-fast-latest are text-only; glm-5p3-flash supports images.

VS Code Chat after FireConnect, with Auto selected under Fireworks

See what FireConnect writes

chatLanguageModels.json

[
  {
    "name": "Fireworks",
    "vendor": "customendpoint",
    "apiType": "chat-completions",
    "apiKey": "${input:chat.lm.secret.fw-...}",
    "models": [
      {
        "id": "auto",
        "name": "Auto",
        "url": "https://api.fireworks.ai/inference",
        "maxInputTokens": 1048575,
        "maxOutputTokens": 131072,
        "vision": true,
        "toolCalling": true
      }
    ]
  }
]

The key is stored separately in state.vscdb, encrypted with Electron safeStorage. On Linux, encryption needs libsecret; without it, VS Code only obfuscates the key and FireConnect warns you.

Platform	chatLanguageModels.json	state.vscdb
Linux	~/.config/Code/User/	~/.config/Code/User/globalStorage/
macOS	~/Library/Application Support/Code/User/	~/Library/Application Support/Code/User/globalStorage/
Windows	%APPDATA%\Code\User\	%APPDATA%\Code\User\globalStorage\

Manual setup

In Copilot Chat, open Language Models, click + Add Models…, and choose Custom Endpoint. Use https://api.fireworks.ai/inference/v1, your Fireworks key, and a model ID such as glm-latest.

Follow the step-by-step screenshots in GitHub Copilot.

Copilot App

OpenAI Chat Completions FireRouter with Provider Keys

The GitHub Copilot desktop app keeps its built-in models and adds Fireworks alongside them. Quit the app before connecting or running off.

FireConnect

fireconnect copilot-app
fireconnect copilot-app status

Reopen the app and pick a Fireworks model in Settings → Model providers.

See what FireConnect writes

FireConnect writes to ~/.copilot/data.db (SQLite, movable with COPILOT_HOME):

Table	What FireConnect adds
model_providers	One Fireworks provider of type openai, with base URL https://api.fireworks.ai/inference/v1 and your key as an Authorization: Bearer header
provider_models	One row per model, with token limits and reasoning efforts (low, medium, high, max)

off deletes the provider and its models. Use --db-path for a non-default database.

Manual setup

In Settings → Model providers, add a provider with the values FireConnect uses:

Field	Value
Base URL	https://api.fireworks.ai/inference/v1
API key	Your Fireworks key
Models	Fireworks IDs, such as glm-latest or kimi-latest

The app’s bring-your-own-key path does not support image input, the hover-card Context row, or AI-credits pricing. Routes that need a local Anthropic key are not available. See Harness Compatibility.

Copilot CLI

OpenAI Chat Completions FireRouter with manual setup

The copilot command (@github/copilot) reads plain JSON under ~/.copilot, separate from the desktop app.

FireConnect

fireconnect copilot-cli
fireconnect copilot-cli status

Start a new copilot session. Switch models with copilot --model fireworks/<name> or /model.

Copilot CLI model picker after FireConnect, with Auto selected

off restores providers.json from its snapshot, or deletes it if FireConnect created it. Use --providers-path for a non-default location.

Manual setup

~/.copilot/providers.json

{
  "providers": [
    {
      "name": "fireworks",
      "type": "openai",
      "wireApi": "completions",
      "baseUrl": "https://api.fireworks.ai/inference/v1",
      "apiKey": "fw_YOUR_FIREWORKS_API_KEY"
    }
  ],
  "models": [
    {
      "id": "glm-latest",
      "provider": "fireworks",
      "wireModel": "glm-latest",
      "name": "GLM (Latest)",
      "maxPromptTokens": 1048576,
      "maxContextWindowTokens": 1048576,
      "maxOutputTokens": 131072,
      "capabilities": { "supports": { "reasoningEffort": true } }
    }
  ]
}

~/.copilot/settings.json

{ "model": "fireworks/glm-latest" }

For a FireRouter route with Claude or GPT models, add a headers map to the provider, such as "headers": { "x-anthropic-api-key": "sk-ant-..." }, and use the router ID, such as firerouter/opus, as the model id and wireModel. FireConnect cannot add these routes to Copilot CLI yet. The harness setup generates the full file.

Use provider-prefixed model IDs such as fireworks/glm-latest. The CLI rejects a bare glm-latest and silently falls back to its configured model.

DeepSeek Harness

OpenAI Chat Completions FireRouter with manual setup

DeepSeek’s coding agent (dsh) runs named profiles, such as tui, web, and headless, under $DSH_HOME, which defaults to ~/.dsh. Restart dsh after changing a profile.

FireConnect

fireconnect deepseek
fireconnect deepseek status

FireConnect writes a fireworks provider to ~/.dsh/settings.yaml and snapshots it under ~/.fireconnect/deepseek/. The default model is auto.

dsh 0.1.7 reads provider settings from each profile’s cordis.patch.yml and ignores ~/.dsh/settings.yaml. If dsh still uses its DeepSeek provider after you connect, use manual setup.

Manual setup

Create the profile folder once, then add a patch to it. Repeat for each profile you use.

dsh --profile tui --dump-config > /dev/null

~/.dsh/profiles/tui/cordis.patch.yml

- id: llm-pi-ai
  config:
    providers:
      fireworks:
        displayName: Fireworks
        apiKeyEnv: FIREWORKS_API_KEY
        api: openai-completions
        baseURL: https://api.fireworks.ai/inference/v1
        models:
          - id: glm-latest
            name: GLM (Latest)
            reasoning: true
            contextWindow: 1048576
            maxTokens: 131072
- id: agent-default-model
  config:
    provider: fireworks
    model: glm-latest

export FIREWORKS_API_KEY="fw_..."
dsh tui

For a FireRouter route with Claude or GPT models, add headers to the provider, such as x-anthropic-api-key: sk-ant-..., and use the router ID as the model. The harness setup generates the full patch.