Use Narwhal with Gemini tools

Q: Which URL field does Antigravity CLI use for Narwhal?

Antigravity CLI uses serverUrl with the Streamable HTTP endpoint https://api.narwhalapi.com/mcp. Add the Authorization Bearer header in headers and verify the connection with /mcp.

Antigravity CLI can connect to Narwhal through Streamable HTTP with an Authorization Bearer header. Individual users have moved from Gemini CLI to Antigravity CLI, whose command is `agy`. Gemini CLI can also connect where it remains available, using its own configuration format.

Quick start

Get a free Narwhal key from https://narwhalapi.com/signup and keep it out of prompts and URLs.
For Antigravity CLI, open ~/.gemini/config/mcp_config.json or the workspace file .agents/mcp_config.json.
Add the remote entry with serverUrl and the Authorization Bearer header, then keep the file private.
Verify the Antigravity connection with /mcp.
Where Gemini CLI is available, run its add command with -s user to keep the key in your user settings.

MCP configuration

Antigravity CLI uses serverUrl for Streamable HTTP and a headers object. The Gemini CLI add command uses -s user, HTTP transport and an Authorization Bearer header.

~/.gemini/config/mcp_config.json

{
  "mcpServers": {
    "narwhal": {
      "serverUrl": "https://api.narwhalapi.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_NARWHAL_API_KEY"
      }
    }
  }
}

Gemini CLI

gemini mcp add -s user --transport http \
  --header "Authorization: Bearer YOUR_NARWHAL_API_KEY" \
  narwhal https://api.narwhalapi.com/mcp

Antigravity CLI documentation does not describe environment variable expansion in headers, so its configuration file stores the key value. Keep the file private and out of version control, whether it lives in your user configuration or the workspace.

Tools you get

Either supported CLI gets all these read-only groups through one Narwhal connection. Initialization and tool discovery are free; each successful call uses one request from the quota shared with REST.

Group	What you can ask for	Tools
Economic indicators	Ask for CPI, inflation, unemployment, labour force participation, GDP, GDP growth and trade by country; coverage differs by indicator.	`economics_get_cpi` `economics_get_inflation` `economics_get_unemployment` `economics_get_labour_force_participation` `economics_get_gdp` `economics_get_gdp_growth` `economics_get_trade` `economics_get_cpi_history` `economics_get_inflation_history` `economics_get_unemployment_history` `economics_get_labour_force_participation_history` `economics_get_gdp_history` `economics_get_gdp_growth_history` `economics_get_trade_history` `economics_read_series_observations`
Currency rates	Ask for current exchange rates, historical rates, currency conversions and rate bars for a currency pair.	`fx_get_rates` `fx_get_rate_history` `fx_convert_currency` `fx_get_rate_bars`
Commodity prices	Ask for spot prices for gold, silver, platinum, palladium, copper, WTI crude oil, and Brent crude oil, their price history, and physical palm oil prices (crude palm oil and fresh fruit bunches).	`commodities_get_spot_price` `commodities_get_price_history` `commodities_list_palmoil_physical_series` `commodities_get_palmoil_physical_price` `commodities_get_palmoil_physical_observations` `commodities_list_physical_series` `commodities_get_physical_series` `commodities_get_physical_latest` `commodities_get_physical_observations`
Releases and events	Ask for official economic release dates and event details before you plan a country briefing.	`economics_list_releases` `economics_get_release` `events_list` `events_get`
Public holidays	Ask for public holidays by country, holidays on a particular date or the next holiday.	`calendars_list_holidays` `calendars_get_holidays_on_date` `calendars_get_next_holiday`
Prediction market odds	Ask for prediction market topics and events with scalar, extreme, timing and binary outcomes, their history, and policy paths by authority.	`predictions_list_topics` `predictions_get_topic` `predictions_list_events` `predictions_get_scalar` `predictions_get_extreme` `predictions_get_timing` `predictions_get_binary` `predictions_get_scalar_history` `predictions_get_extreme_history` `predictions_get_timing_history` `predictions_get_binary_history` `predictions_get_policy_path` `predictions_get_policy_path_history`
Government bond yields	Ask for government bond yield curves for the US, the UK, Germany, Japan, and Canada through the same Narwhal connection.	`economics_get_yield_curve` `economics_get_yield_curve_history`

Example prompts

Get the latest inflation value for Japan.
Show the current USD/IDR exchange rate.
Get the current gold spot price.
Find the next official CPI release date for the United States.
List the public holidays in Indonesia for the current year.

Common workflows

Prepare a Japan inflation briefing

Japanese inflation is available through economics_get_inflation in either CLI. Select Japan for the latest reported percentage changes.

Check a rate before converting currency

Check USD/IDR with fx_get_rates, using USD as the base and IDR as the quote currency for the current indicative rate.

Review commodity prices for your analysis

commodities_get_spot_price accepts copper and a quote currency. The result is the current indicative spot price.

Check timing for the next CPI release

Include the United States and a date window of up to 366 days in an economics_list_releases request to locate the next official CPI release.

Tips

Use serverUrl in Antigravity CLI; httpUrl and the old SSE transport are unsupported there.
For Gemini CLI, -s user keeps the key in ~/.gemini/settings.json; the default project scope writes it to the repository's .gemini/settings.json.
Gemini CLI settings use an entry under mcpServers with httpUrl and headers.

FAQ

Can individual Gemini users still use Gemini CLI?

Individual users have moved from Gemini CLI to Antigravity CLI, whose command is agy. Gemini CLI has a separate configuration format where it remains available.

Which URL field does Antigravity CLI use for Narwhal?

Antigravity CLI uses serverUrl with the Streamable HTTP endpoint https://api.narwhalapi.com/mcp. Add the Authorization Bearer header in headers and verify the connection with /mcp.

Can Antigravity read the key from an environment reference?

The docs do not describe environment variable expansion in headers, so the file stores the key value. Keep the user or workspace configuration file private and out of version control.

Troubleshooting

Symptom	Check
Narwhal does not appear in Antigravity CLI	Check the user or workspace `mcp_config.json` entry, confirm it uses `serverUrl` and inspect `/mcp`.
The server returns `401 invalid_api_key`	Check that the header contains `Bearer` followed by a space and an active key, rather than an unexpanded environment reference.
An Antigravity connection using httpUrl fails	Change the remote entry to `serverUrl` and Streamable HTTP; Antigravity does not support `httpUrl` or the old SSE transport.
Gemini CLI no longer serves the account tier	Use Antigravity CLI for individual accounts and follow its configuration format instead of the Gemini CLI settings format.