fcc-spectrum-mcp-server

@cyanheads/fcc-spectrum-mcp-server Search FCC radio licenses, find nearby licensed sites, and see who is licensed on a frequency via MCP. STDIO or Streamable HTTP. 5 Tools • 2 Resources

Public Hosted Server: https://fcc-spectrum.caseyjhand.com/mcp

Overview

US radio spectrum licensing from the FCC's Universal Licensing System, searchable offline. Look up a callsign, licensee, or market; read a license's sites, antennas, frequencies, and microwave paths; find transmitters near a point; and see who's authorized on any frequency or band. Covers land mobile, microwave, cellular, paging, amateur, and more; full-power broadcast stations and satellite earth stations aren't included. No API key required.

Tools

Resources

License records are also reachable via fcc_spectrum_get_license. The investigation guide is available to clients through resources/list and resources/read.

Capability reference

fcc_spectrum_search_licenses tool

• Filters: callsign, licensee (every word must match the start of a word in the name), frn, market_code (a geographic-area license's market, matched exactly: PEA016, CMA020, D06037, NW; pea16 reads as PEA016), radio_service, and state (the licensee's mailing state) — at least one required; status narrows to A (default), C, E, L, P, T, X, or any
• Positive integer limit (default 25, capped at 100) with cursor paging; each row carries the usi to pass to fcc_spectrum_get_license, plus isLease, licenseeRedacted, and location and frequency counts
• Typed errors: no_criteria, unknown_radio_service, service_not_indexed, invalid_cursor, index_not_ready

fcc_spectrum_get_license tool

• Exactly one of callsign or usi (identifier_required otherwise); a callsign shared by several records returns the active one, else the most recent, and lists the others in otherCallsignRecords
• Pages large records: whole locations up to 50 sites, 100 antennas, and 100 microwave paths (a location larger than that is listed alone), up to 100 leases, and max_frequencies frequency rows (positive integer, default 100, capped at 1000) per call; nextLocationOffset and nextLeaseOffset feed location_offset and lease_offset on the next call
• Microwave paths (FCC PA records) are listed in paths under the antenna that transmits them: path number, type, passive flag, and receiving callsign as filed, and a receive end with its location and antenna numbers, coordinates when the license files exactly one valid site under the receive number, siteCount when it files none or several, and antennaFiled: false when no antenna record matches. pathTotal counts the record's paths across all locations (absent on an index built before paths were indexed, until mirror:init rebuilds it), and when more locations follow, the notice reports the paths listed against it
• location_number starts the locations at a site's locationNumber from fcc_spectrum_find_transmitters or fcc_spectrum_search_frequencies; combined with a nonzero location_offset it fails (location_start_conflict)
• A miss returns found: false with guidance and up to 5 callsign-prefix candidates, not an error; technicalRetained: false marks a record whose status keeps no sites or frequencies

fcc_spectrum_find_transmitters tool

• latitude / longitude as decimal degrees or DMS strings, radius_km 0.1–100 (default 5); optional frequency_low / frequency_high in unit (kHz, MHz default, GHz), radio_service, location_type (one ULS location type code, case-insensitive: F keeps fixed sites only, M mobile and T temporary-fixed areas), and status (A default, L, X, or any for all three)
• Sites nearest first, positive integer limit (default 25, capped at 100) with cursor paging; each site lists up to max_frequencies_per_site frequencies (positive integer, default 10, capped at 50), with frequencyCount carrying the full count
• Each site carries locationTypeCode, locationTypeLabel, radiusKm, locationClassCode, and locationClassLabel when filed; a mobile or temporary-fixed area is returned at its filed center, and distanceKm measures to that center. location_class (case-insensitive C, L, P, R, or T) keeps one FCC class; results describe authorization, not actual on-air activity
• Typed errors: invalid_frequency_range, unknown_radio_service, service_not_indexed, invalid_cursor, index_not_ready

fcc_spectrum_search_frequencies tool

• frequency_low required, frequency_high optional, in unit; a site assignment matches when its occupied band (widened by its emission bandwidth) overlaps the query, a market block when its filed edges do; kind is site, market, or both (default)
• Narrow by state, radio_service, licensee, frn, market_code, and status (A default, L, X, any); positive integer limit (default 50, capped at 200) with cursor paging, frequency ascending; each row's kind says whether it is a site assignment or a market block
• market_code and frn filter site rows and market rows alike; an frn search returns individual licensees redacted. Single-site rows carry locationTypeCode, locationTypeLabel, radiusKm, locationClassCode, and locationClassLabel when filed; shared-number rows and market blocks omit them
• Typed errors: invalid_frequency_range, unknown_radio_service, service_not_indexed, invalid_cursor, index_not_ready

fcc_spectrum_list_reference tool

• topic: radio_services, station_classes, license_statuses, location_types, antenna_types, applicant_types, operator_classes, or coverage; filter narrows radio services and station classes to entries containing every token in their code and label, with case/accent folding and punctuation separating tokens
• A searchable filter must contain an ASCII letter or digit (invalid_filter otherwise); blank means unset. Other topics ignore the filter and say so
• Decode a station class with {"topic":"station_classes","filter":"FXO"} (FXO is Operational Fixed, FB2 Mobile Relay, MO Mobile). Labels come from a bundled 266-code table of the FCC's uls_code_definitions_20240718.txt (archived copy); an unmapped code returns no entries. These are licensed categories, not actual on-air activity
• coverage reports index.status (none, building, ready), per-group record, site, and frequency counts with snapshot times, and whether redaction is on; it works before the index is built. index.antennaCoverageIncomplete: true marks an older index that dropped unnumbered antennas, and index.pathCoverageIncomplete: true one built before microwave paths were indexed; bun run mirror:init rebuilds either

fcc-spectrum://license/{callsign} resource

• The first page of fcc_spectrum_get_license (up to 100 frequency rows, with its microwave paths) as application/json, with dataAsOf, totals, and a notice naming the tool call that reads the rest; cached 1 hour
• Typed errors: index_not_ready, license_not_found

Features

Built on @cyanheads/mcp-ts-core: stdio and Streamable HTTP transports, pluggable auth (none / jwt / oauth), swappable storage (in-memory, filesystem, Supabase, Cloudflare KV/R2/D1), structured logging with optional OpenTelemetry tracing.

FCC ULS-specific:

• Keyless and local at request time — every query reads the SQLite index; network access is needed only to build and refresh it
• Occupied-band frequency matching — each assignment's band is widened by the bandwidth parsed from its emission designators, so a query near a wide channel's edge still finds it
• Spectrum leases are first-class records — isLease marks them, the licensee shown is the lessee, and lease links are listed in both directions
• Site state is derived from coordinates when the filing leaves it blank (common for microwave and BRS/EBS), and flagged stateFromCoordinates
• Individual licensees are redacted by default, and contact details are never ingested — see Individual-licensee redaction

Agent-friendly output:

• Freshness and filter echo — every data response carries dataAsOf, an