@cyanheads/openfec-mcp-server

Public Hosted Server: https://openfec.caseyjhand.com/mcp

Overview

US federal campaign finance data from the FEC's OpenFEC API. Search candidates, committees, and filings, trace contributions (Schedule A), disbursements (Schedule B), and independent and coordinated party expenditures (Schedules E/F), and look up election races, legal documents, and filing deadlines. Runs as a stdio process, a local Streamable HTTP server, or the public hosted endpoint above.

Tools

Resources

The same data is reachable through openfec_search_candidates, openfec_search_committees, and openfec_lookup_elections for tool-only clients.

Prompts

Related MCP server: fec-mcp

Capability reference

openfec_search_candidates tool

• query name search filtered by state, district, office, party, cycle, election_year, incumbent_challenge, candidate_status, and has_raised_funds, up to 100 per page; or a candidate_id lookup (H/S/P + eight letters or digits) returning one full record

• include_totals (default on for an ID lookup) adds per-cycle totals rows and caps a search page at 35 candidates when cycle or election_year scopes the totals, 5 when they span every cycle; candidates the totals fetch didn't reach are listed in missing_totals

• Typed errors: candidate_not_found, inputs_not_applicable_to_id_lookup

openfec_search_committees tool

• query name search filtered by candidate_id, state, party, committee_type, designation, cycle, and treasurer_name, up to 100 per page; or a committee_id lookup (C + eight digits)

• Typed errors: committee_not_found, inputs_not_applicable_to_id_lookup

openfec_get_committee_totals tool

• mode: "single" (default) takes a committee_id and returns one row per two-year cycle; mode: "by_entity_type" ranks every committee of one entity_type (presidential, pac, party, pac-party, house-senate, ie-only), filterable by state, type, designation, organization type, and receipts/disbursements bounds; up to 100 per page

• Rows carry receipts, disbursements, cash on hand, debts, and the itemized/unitemized split; the output mode says whether rows are cycles or committees

• Typed errors: committee_id_required_for_single_mode, entity_type_required_for_group_mode, committee_totals_not_found

openfec_search_contributions tool

• itemized (default) needs a committee_id and filters by contributor name, employer, occupation, city, state, ZIP, date and amount ranges, and is_individual, 30 rows per page; by_size / by_state take a committee_id or candidate_id, by_employer / by_occupation a committee_id

• The output mode becomes by_size_candidate or by_state_candidate when scoped by candidate, a different row shape; itemized responses carry next_cursor, count, and count_is_approximate

• Typed errors: itemized_requires_committee_id, aggregate_requires_committee_id

openfec_search_disbursements tool

• committee_id required in every mode: itemized (default; recipient name, state, city, and committee ID, description, purpose category, date and amount ranges, 30 rows per page), by_purpose, by_recipient, by_recipient_id

• Itemized responses carry next_cursor, count, and count_is_approximate; aggregate modes page by number

openfec_search_expenditures tool

• itemized (default) filters by committee, candidate, support_oppose, payee, targeted office/state/district, party, is_notice (24/48-hour notices), dates, and amounts; most_recent defaults to true; 60 rows per page when scoped by committee_id, 30 otherwise

• by_candidate totals need a candidate_id or a full race scope (candidate_office=P alone, S plus candidate_office_state, H plus state and candidate_office_district), or fail as by_candidate_requires_scope

openfec_search_coordinated_expenditures tool

• Scope by spending party committee_id, benefiting candidate_id, cycle, payee, dates, and amounts; unscoped queries span all years

• Page-based, 80 rows per page when scoped by committee_id and 25 otherwise; rows carry subordinate_committee_id, the committee the spending is attributed to

openfec_search_filings tool

• Filters: committee_id, candidate_id, filer_name, form_type (F3, F3P, F3X, F24, F1, F2, F5), report_type, report_year, cycle, is_amended, and receipt date range; 65 rows per page

• most_recent defaults to true, hiding superseded amendments; rows carry form and report type, financial totals, and pdf_url

openfec_lookup_elections tool

• office and an even cycle are required; Senate also needs state and House state plus district, unless a zip scopes a search

• mode: "search" (default) returns the race's candidates with totals and candidate_pcc_id / candidate_pcc_name, that cycle's principal campaign committee; mode: "summary" returns one aggregate race row

• Typed errors: cycle_must_be_even, missing_state_for_office, missing_district_for_house, summary_does_not_support_zip

openfec_search_legal tool

• type (advisory_opinions, murs, adrs, admin_fines, statutes), query, ao_number, case_number, respondent, citations, penalty bounds, or dates; at least one is required (missing_filter), and a date bound needs type plus a date_kind that type records

• Citations, penalty bounds, respondent, ao_number, and case_number each filter only some types; one sent with a type it doesn't filter fails as filter_not_valid_for_type, and with type omitted the search returns only the types they all apply to, with a total over those types. On MURs and ADRs a citation can't be combined with case_number, respondent, a penalty bound, or an open/close date bound, which upstream would ignore; the two citation fields together match either one

• Citations take the form upstream parses — 52 U.S.C. 30104 or 11 CFR 110.1 (USC, C.F.R., §, and suffixes like 30104(g) are fine); a bare 30106 or 110.1 fails as invalid_citation instead of silently returning unfiltered results. One citation per field: upstream applies only the first citation in a value, so 52 U.S.C. 30104, 52 U.S.C. 30118 fails the same way

• Offset paging via from_hit / hits_returned, up to 200 per type within a 10,000-result window

• Results are trimmed: documents becomes document_count and document_categories, dispositions becomes disposition_count and disposition_categories, highlights stop at 3 with their <em> match markup removed and render one per line, and commission_votes shrink to a date and a 200-character action; openfec_get_legal_document returns the full record

• Each response stays under 100,000 bytes: whole results are admitted one type at a time until the next would not fit, and a page that held some back reports truncated, shown, and nextFromHit — the from_hit that continues each type, passed back with that type

openfec_get_legal_document tool

• doc_type is the plural of a search result's document_type (mur → murs); no is that result's no field

• Returns the untrimmed record, including documents, commission_votes, and dispositions; fails as legal_document_not_found

• A record over 100,000 bytes returns its scalar fields, the arrays that fit (smallest first), and withheld — each held-back array with its entry count and size; re-call with array and offset for that array's entries while they fit, plus next_offset. An array the record lacks fails as array_not_in_record

openfec_lookup_calendar tool

• events (default; category, one of 18 codes, and description), filing_deadlines (report_type, report_year), or election_dates (state, office, district, election_year); min_date / max_date apply in every mode, up to 100 per page

• A district filter never matches an at-large race; pair it with state

openfec://candidate/{candidate_id} resource

• Candidate record merged with its financial totals and principal_committees (current designation P, not scoped to a cycle)

• candidate_id comes from openfec_search_candidates; fails as candidate_not_found

openfec://committee/{committee_id} resource

• Committee record merged with its financial totals, which are absent for a committee that files no Form 3/3X/3P

• committee_id comes from openfec_search_committees; fails as committee_not_found

openfec://election/{cycle}/{office} resource

• Presidential races (office P), with totals for the full election period

• First page only: a longer race carries truncation_notice pointing to openfec_lookup_elections, and an empty one empty_result_notice

openfec://election/{cycle}/{office}/{state} resource

• Senate races, or an at-large House race in a single-district state (office S or H)

• Same first-page limit and notices as the presidential template

openfec://election/{cycle}/{office}/{state}/{district} resource

• House district races (office H)

• Same first-page limit and notices as the presidential template

openfec_money_trail prompt

• Arguments: candidate_name or candidate_id (one required), optional cycle

• Seven steps: identify the candidate, resolve the cycle's principal committee via candidate_pcc_id, then direct fundraising, independent expenditures, coordinated party spending, disbursements, and a synthesis

openfec_campaign_analysis prompt

• Arguments: candidate_name or candidate_id (one required), optional cycle

• Seven steps: candidate overview, principal committee and per-cycle trajectory, fundraising mix, burn rate, competitive position, outside money, and an assessment

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.

OpenFEC-specific:

• Type-safe client for the OpenFEC REST API with retry and a configurable timeout; error messages have the API key stripped and HTTP failures carry recovery hints

• Cycles are even years covering two calendar years (2024 = Jan 2023 – Dec 2024); itemized Schedule A/B/E default to the current cycle when cycle is omitted, and election_full (default true) widens a race total to the full election period (4yr president, 6yr senate, 2yr house)

• Itemized contributions and disbursements scope to a committee_id, not a candidate_id. Committee designation and principal_committees reflect current designation only, so for a cycle's principal committee read candidate_pcc_id from openfec_lookup_elections

• Itemized Schedule A/B/E page with an opaque next_cursor, valid only for an otherwise-identical call; other tools page by number, and legal search by offset

Agent-friendly output:

• Effective-query echo: every tool response carries search_criteria with the post-default filters, and an empty result carries a notice on how to broaden it

• Response budget of 100,000 bytes per surface: high-volume tools cap rows per page and report truncated, shown, and cap when a page falls below the requested per_page (page-based tools also echo the applied size in pagination.per_page); legal search holds back whole results and reports nextFromHit, and a large legal document pages its arrays by offset; a single-committee query lifts that committee into one top-level committee field instead of repeating it per row

• Typed contracts: multi-mode tools echo the resolved mode and reject a filter the mode can't apply (itemized_only_filters_in_aggregate_mode, inputs_not_applicable_to_mode) instead of dropping it; every failure carries a typed reason and recovery text, and estimated totals are flagged count_is_approximate

Getting started

Public Hosted Instance

A public instance is available at https://openfec.caseyjhand.com/mcp — no installation required. Point any MCP client at it via Streamable HTTP:

{
  "mcpServers": {
    "openfec-mcp-server": {
      "type": "streamable-http",
      "url": "https://openfec.caseyjhand.com/mcp"
    }
  }
}

Self-Hosted / Local

Add the following to your MCP client configuration file.

{
  "mcpServers": {
    "openfec-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/openfec-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "FEC_API_KEY": "your-api-key"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "openfec-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/openfec-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "FEC_API_KEY": "your-api-key"
      }
    }
  }
}

Or with Docker:

{
  "mcpServers": {
    "openfec-mcp-server": {
      "type": "stdio",
      "command": "docker",
      "args": ["run", "-i", "--rm", "-e", "MCP_TRANSPORT_TYPE=stdio", "-e", "FEC_API_KEY=your-api-key", "ghcr.io/cyanheads/openfec-mcp-server:latest"]
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 FEC_API_KEY=your-key bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• Bun v1.4.0 or higher (or Node.js v24+).

• Optional: a free OpenFEC API key raises the rate limit from 30 to 1,000 requests per hour over the default DEMO_KEY.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/openfec-mcp-server.git

2. Navigate into the directory:

cd openfec-mcp-server

3. Install dependencies:

bun install

4. Configure environment:

cp .env.example .env
# edit .env and set FEC_API_KEY (optional)

Configuration

See .env.example for the full list of optional overrides.

Running the server

Local development

• Build and run:

  bun run rebuild
  bun run start:stdio   # or start:http

• Run checks and tests:

  bun run devcheck      # Lint, format, typecheck, security audit
  bun run test          # Vitest test suite
  bun run lint:mcp      # Validate MCP definitions against spec

Docker

docker build -t openfec-mcp-server .
docker run --rm -e FEC_API_KEY=your-key -p 3010:3010 openfec-mcp-server

The Dockerfile defaults to HTTP transport, stateless session mode, and logs to /var/log/openfec-mcp-server. OpenTelemetry peer dependencies are installed by default — build with --build-arg OTEL_ENABLED=false to omit them.

Project structure

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic

• Use ctx.log for logging, ctx.state for storage

• Register new tools and resources in the barrels at src/mcp-server/*/definitions/index.ts

• Wrap the OpenFEC API: validate raw → normalize to domain type → return the output schema; never fabricate fields the upstream response omitted

Contributing

Issues are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.