SHEARLINE

What SHEARLINE MCP server does

The SHEARLINE MCP server exposes analyst-oriented severe-weather data for a latitude and longitude in the United States. Its tools cover active tornado, severe-thunderstorm, and flash-flood warnings; SPC convective outlooks; RAP-derived instability and shear; MRMS hail and rotation estimates; GOES-East lightning; real-time and historical Local Storm Reports; radar metadata; and a synthesized threat brief.

Warning results include polygon information, point-in-polygon status, expiration, storm motion, and machine-readable Impact-Based Warning details such as hail, wind, and tornado threat tags. Environmental calculations include CAPE, CIN, LCL, vertical shear, storm-relative helicity, effective inflow measures, SCP, and STP. The trend tool compares several RAP forecast hours to describe whether conditions are intensifying, stabilizing, or holding steady.

How it works

Each tool accepts geographic coordinates, with radius, time-window, date, or outlook-day parameters where applicable. The threat brief runs the available analyses concurrently and combines them into a threat level, ranked hazards, environmental context, nearby storm signatures, stated decision logic, and an attention window.

Responses use structured JSON. Numeric values identify their units, while an interpretation field provides plain-language context. A degraded field identifies upstream sources that were unavailable, allowing partial results to be distinguished from a complete failure. Responses also include a safety disclaimer and a semver-stable schema version.

The underlying inputs are public and anonymous. RAP profile quantities are calculated with MetPy, while radar-derived values come from MRMS and the nearest WSR-88D metadata tool. Historical storm reports cover approximately 2005 onward but represent preliminary LSR data rather than the final NCEI record.

Setup and configuration

Python 3.12 or newer and uv are required. The published package can be launched without a permanent installation:

uvx shearline

For Claude Code, register the command with claude mcp add shearline -- uvx shearline. Claude Desktop can use a server entry whose command is uvx and whose argument is shearline.

The SHEARLINE MCP server can also expose streamable HTTP:

uvx shearline --http --port 8741

The MCP endpoint is served at /mcp. HTTP deployments can set SHEARLINE_PORT, SHEARLINE_RATE_RPM, SHEARLINE_RATE_BURST, SHEARLINE_HTTP_LOG, SHEARLINE_LOG_LEVEL, and SHEARLINE_UPSTREAM_CONCURRENCY. These settings control the macOS launcher port, per-client rate limiting, request logging, logger verbosity, and concurrent upstream fetches. No API keys are needed.

Tools and capabilities

Available tools include:

• get_active_warnings for nearby warning polygons, IBW tags, motion, expiration, and point inclusion.
• get_spc_outlook for categorical and hazard-specific SPC probabilities on outlook days one through three.
• get_point_environment and get_environment_trend for current RAP-derived parameters and short forecast trajectories.
• get_mrms_severe, get_radar_snapshot, and get_lightning for radar, hail, rotation, echo-top, and lightning indicators.
• get_storm_reports and get_historical_storm_reports for current-window or date-specific reported impacts.
• get_threat_brief for a concurrent synthesis of the other severe-weather signals.

Limitations and notes

The SHEARLINE MCP server is informational and does not replace official NWS warnings, weather.gov, or local authorities. Radar products, model environments, reports, and public feeds can be delayed, incomplete, or degraded; the response metadata identifies reported upstream failures. Historical reports are preliminary LSRs, and derived radar or model quantities should be interpreted as analysis rather than direct observation. The HTTP transport applies client rate limits and can return HTTP 429 when its configured token bucket is exceeded.