Harness Compatibility

Use this page to check whether FireConnect can add FireRouter to your harness and what it changes about Model Context Protocol (MCP) configuration. For setup commands and restart rules, see Coding Harnesses.

FireRouter
MCP

Harness	Request API	FireRouter compatibility	Local provider credentials
Claude Code	Messages	Supports `firerouter` and `firerouter/...` IDs	Anthropic login, OAuth, or `ANTHROPIC_API_KEY`; OpenAI key
Claude Agent SDK	Messages	Supported when the SDK reads the user settings written by FireConnect	Same as Claude Code
OpenCode	Chat Completions	Supports `firerouter` and `firerouter/...` IDs	Anthropic and OpenAI keys
Codex	Responses	Supports `firerouter` and `firerouter/...` IDs	`ANTHROPIC_API_KEY` and `OPENAI_API_KEY` environment references
Codex app, ChatGPT desktop	Responses	Uses the FireRouter IDs registered through the shared Codex configuration	No separate local provider-key configuration
Pi	Chat Completions	Supports `firerouter` and `firerouter/...` IDs	Anthropic and OpenAI keys
Cursor IDE	Chat Completions	Supports `firerouter` and `firerouter/...` IDs. Closed models need Provider Keys	None
VS Code	Chat Completions	Supports `firerouter` and `firerouter/...` IDs	Anthropic and OpenAI keys
Copilot App	Chat Completions	Supports `firerouter` and `firerouter/...` IDs. Closed models need Provider Keys	None
Copilot CLI	Chat Completions	Supports `firerouter` and `firerouter/...` IDs. Closed models need Provider Keys or manual setup	Provider-key headers in manual setup
DeepSeek Harness	Chat Completions	Supports `firerouter` and `firerouter/...` IDs. Closed models need Provider Keys or manual setup	Provider-key headers in manual setup
Claude Desktop	Messages	Not offered. The picker lists `auto` and Fireworks models	Not applicable

Provide a local key. Where a harness supports one, pass it when you connect, or store it once for every harness:

fireconnect opencode --model firerouter/opus --anthropic-api-key "$ANTHROPIC_API_KEY"
fireconnect configure --anthropic-api-key "$ANTHROPIC_API_KEY"
fireconnect configure --openai-api-key "$OPENAI_API_KEY"

Both keys are optional. FireConnect connects without them and never prompts for an OpenAI key.
FireConnect also reads ANTHROPIC_API_KEY and OPENAI_API_KEY from your environment.
Codex stores environment references, so FireConnect adds a line to your shell config that exports the saved keys. Open a new terminal before starting Codex.
The OpenAI key goes out on bare firerouter and on routes that name a GPT model ID, such as firerouter/gpt-5.6-sol. Family routes such as firerouter/sol and firerouter/astra need an OpenAI Provider Key or manual setup.

Harnesses without a local key. Cursor IDE, Copilot App, Copilot CLI, and DeepSeek Harness accept every FireRouter ID, including bare firerouter. Without a matching Provider Key, FireRouter serves those routes with open models only.

Cursor IDE and the Copilot App cannot send extra headers, so closed models there need a Provider Key.
Copilot CLI and DeepSeek Harness can send the headers with manual setup.

Provider Keys is not yet available on every account; contact the Fireworks team to enable it. For direct HTTP calls, see APIs and SDKs or LLM Gateways.Automated live-inference validation covers Claude Code, OpenCode, Codex, Pi, and DeepSeek Harness. Cursor IDE, VS Code, Copilot App, Copilot CLI, and ChatGPT desktop are validated at the configuration layer.

Your MCP servers keep working after you connect a harness to Fireworks. FireConnect changes where model requests go, not which tools the harness loads. Fireworks models call MCP tools the same way the harness’s default models do.

Your servers stay

FireConnect keeps every MCP server you configured, and fireconnect <harness> off leaves them in place.

Tool search stays on

In Claude Code, FireConnect sets ENABLE_TOOL_SEARCH so large MCP tool sets still load on demand.

Web search is built in

The Fireworks WebSearch MCP is retired. Claude Code’s native WebSearch tool replaces it.

What FireConnect changes

Harness	What happens to MCP
Claude Code	Your servers stay in `~/.claude.json`. FireConnect removes only its retired `fireworks-websearch` server and sets `ENABLE_TOOL_SEARCH`
Codex	Your servers stay in `[mcp_servers]` in `~/.codex/config.toml`
OpenCode	Your servers stay in the `mcp` block of `opencode.json`
Codex app	FireConnect doesn’t touch MCP. Set up servers in the app as usual
ChatGPT desktop	Unreliable MCP servers and plugins don’t work reliably while FireConnect is on
Pi, Cursor IDE, VS Code, Copilot App, Copilot CLI, DeepSeek Harness	FireConnect doesn’t touch MCP. Set up servers in the harness as usual
Claude Agent SDK	FireConnect doesn’t touch MCP. MCP follows the setting sources your application loads
Claude Desktop	Third-party mode hides the connector browser. Run `fireconnect claude-desktop mcp sync` after `on` to import your connectors, then sign in to each once. See Claude Desktop

MCP servers and plugins in ChatGPT desktop don’t work reliably while FireConnect is on. If you depend on them there, run fireconnect codex off before using them.

Check that an MCP tool works

Connect the harness

fireconnect claude

Use fireconnect codex or fireconnect opencode for the other harnesses.

Confirm the server is configured

claude mcp list
# docs: npx -y your-mcp-server - ✔ Connected

# ~/.codex/config.toml, next to the settings FireConnect adds
[mcp_servers.docs]
command = "npx"
args = ["-y", "your-mcp-server"]

// ~/.config/opencode/opencode.json
{
  "mcp": {
    "docs": {
      "type": "local",
      "command": ["npx", "-y", "your-mcp-server"],
      "enabled": true
    }
  }
}

In Claude Code, add a server with claude mcp add <name> -- <command>.

Ask the model to call a tool

Start a new session and ask for something only the tool can answer, such as “Call the docs search tool and summarize the first result.” The harness shows the tool call, and the answer uses the tool’s output.

Setting up Claude Code by hand? Add "ENABLE_TOOL_SEARCH": "true" to env in ~/.claude/settings.json. Claude Code turns MCP tool search off when ANTHROPIC_BASE_URL points anywhere other than Anthropic.

Upgrading from the Fireworks WebSearch MCP? fireconnect claude removes the fireworks-websearch server for you and leaves your other servers in place. See Web Search for which harnesses have native web search.

Troubleshooting

Nothing changed after --model

Restart or reopen the harness. Claude Code and Codex load a new model in a new or resumed session. See Coding Harnesses for each harness.

A FireRouter route never uses Claude or GPT

The harness cannot send a local provider key, or the route does not pick up your saved key. Connect the matching Provider Key, use manual setup on a harness that can send headers, or use a harness that supports a local key.

Claude Code says auto mode classifier requests are billed

Expected once per session. Auto mode’s safety checks run on your Sonnet slot, so they bill to Anthropic. To bill them at Fireworks rates, pin Sonnet with fireconnect claude --sonnet <id>.

Microsoft Foundry

FireRouter is not available on Microsoft Foundry, and Foundry support differs by harness. See the compatibility matrix in Foundry for Coding Harnesses, including Claude Code through a gateway.

Coding Harnesses: connect commands, files changed, and restart rules
FireRouter: router IDs and composition
Provider Keys: account-level closed-model credentials
Routing Preferences: quality and savings controls by harness

Nexus

Connect

Choose models

Operate

Reference

Your servers stay

Tool search stays on

Web search is built in

What FireConnect changes

Check that an MCP tool works

Troubleshooting

Microsoft Foundry

Your servers stay

Tool search stays on

Web search is built in

​What FireConnect changes

​Check that an MCP tool works

​Troubleshooting

​Microsoft Foundry

​Related setup

What FireConnect changes

Check that an MCP tool works

Troubleshooting

Microsoft Foundry

Related setup