GedFire

GedFire is a command-line tool that lets an AI agent help with your family history research without giving it write access to your GEDCOM file. The agent writes its findings as a JSON proposal; you review it, approve the items you want, and GedFire applies them, keeping each citation attached to the claim it supports. It can then generate a static family-page site from the result.

agent research -> JSON proposal -> your review -> verified GEDCOM -> static HTML

GedFire works only with local files and makes no network requests. Your chosen AI client controls where tool results are processed.

Why not just let the agent edit the file? GEDCOM looks like plain text, but the level hierarchy, cross-record pointers, and continuation rules are easy to get wrong — agents asked to rewrite raw GEDCOM tend to produce broken levels, dangling references, or files that no longer validate. GedFire instead applies typed operations to a parsed document and refuses to write anything invalid, so a valid input file stays valid. As a bonus, the agent doesn't have to read and reproduce whole GEDCOM records, which saves a lot of tokens.

Browse a live generated family-page site → Generated from the synthetic family in docs/demo, rebuilt by CI on every push. Facts retain their source citations, available as hover-popover footnotes in the HTML.

MCP server

GedFire also runs as a Model Context Protocol server, so clients including Claude Desktop, Claude Code, Cursor, Windsurf, Gemini CLI, and Codex can query your GEDCOM directly, in conversation, instead of shelling out to the CLI:

gedfire mcp --input family.ged

Install the global .NET tool before configuring a client. The command above starts a long-running stdio server, so waiting silently for a client connection is normal.

Most MCP clients accept the same local stdio server entry. Add this block to the client's MCP configuration, replacing the GEDCOM path with an absolute path:

{
  "mcpServers": {
    "gedfire": {
      "command": "gedfire",
      "args": [
        "mcp",
        "--input",
        "/absolute/path/to/family.ged"
      ]
    }
  }
}

Use that mcpServers entry in the location your client supports:

Codex uses TOML instead of the JSON wrapper above. Add this to .codex/config.toml in the project or ~/.codex/config.toml:

[mcp_servers.gedfire]
command = "gedfire"
args = ["mcp", "--input", "/absolute/path/to/family.ged"]

Two optional flags follow --input in args (or after --input <path> on the claude mcp add / TOML command lines above):

On Windows, JSON paths use escaped backslashes such as C:\\Users\\me\\family.ged; forward slashes also work. The gedfire command must be available on the environment PATH inherited by the client, or command must contain the absolute path of the executable. GedFire needs no environment variables, API keys, or other credentials.

Restart or reload the client after changing its configuration, approve the local server if prompted, and confirm that it discovers find_person, date_calc, get_document_stats, get_record, describe_changeset_ops, validate_changeset, validate_document, and apply_changeset.

As a smoke test, ask "How many people and families are in this file?" The client should call get_document_stats and report both counts.

The server binds to one document over stdio and exposes eight tools. Seven are read-only; apply_changeset is the only one that writes to the file, and only after validation and in-memory verification both pass (or not at all, if the server was started with --read-only). The server also watches the bound file and reloads automatically if it changes on disk — including a change apply_changeset itself just wrote — no restart needed:

date_calc, find_person, get_document_stats, and get_record also have a one-shot CLI mirror — find-person, get-record, get-document-stats, and date-calc — that runs the same engine and prints the same JSON without starting a server. validate_changeset and apply_changeset mirror the CLI's own apply --dry-run and apply, and validate_document mirrors validate, described under "Command reference" below, rather than having a same-named CLI counterpart of their own.

For example, an MCP client can call find_person with:

{
  "query": "Frederick Morrill",
  "hints": {
    "birth": { "year": 1841, "place": "New Hampshire" },
    "parents": { "father": "Wyman Morrill" },
    "spouse": {
      "name": "Sarah Blake",
      "marriage": { "year": 1865, "place": "Maine" }
    }
  },
  "maxResults": 20
}

Every hint leaf is optional, but each supplied object must contain at least one fact. Birth and death places are event-specific; census or otherwise unclassified places are not hints. Parent names require a known father or mother role. All fields under spouse describe one marriage and are never combined across different marriages. Hints rank only people already recalled by the name query, and missing candidate data is not penalized.

Every result has the same top-level fields: matchType, confidentMatchXref, confidentMatchScore, person, candidates, suggestions, totalMatches, and truncated. Candidates and suggestions always include matchScore. Scores rank evidence within this matcher; they are not statistical probabilities. Use matchType and confidentMatchXref to decide whether the lookup resolved one person. maxResults changes only the returned comparison-list length, never recall, ranking, or confidence classification.

apply_changeset is the only tool that writes to the file, and it applies the same numbered JSON changeset you'd review by hand — an agent proposing a change still writes a changeset for you to see, not a second, unreviewed path to your data; apply_changeset is how that reviewed changeset gets applied without leaving the conversation, instead of shelling out to gedfire apply. Start the server with --read-only if you want an agent to look and propose but never write, regardless of what it's asked to do. GedFire itself makes no network requests and sends no telemetry; the MCP client you choose is responsible for what it does with tool results. Every returned xref belongs to the one GEDCOM bound by --input; do not reuse it against another file.

If the server does not start, run gedfire --version in a new terminal to confirm that the installed command is available, then verify the input path exists. Check the client's MCP status or server log for startup errors. An absolute executable path in command avoids PATH differences between a terminal and a desktop application.

Why should I use GedFire?

• GedFire keeps the agent's hands off your master file. The agent writes a numbered JSON proposal instead of editing the GEDCOM, so nothing changes until you've reviewed it.
• GedFire applies changes as typed operations against a parsed document rather than raw text edits, so it can't produce broken levels, dangling pointers, or a file that no longer validates.
• You can dry-run a proposal with --dry-run and then apply all of its numbered items or only the ones you agree with.
• Citations stay attached to the claims they support, from the agent's finding all the way into the GEDCOM and the generated pages.
• GedFire generates a static family-page site directly from the reviewed GEDCOM, so the published pages and the evidence never drift apart.
• Because the agent works with compact operations instead of reading and reproducing whole GEDCOM records, the workflow uses considerably fewer agent tokens.
• GedFire is also a scriptable GEDCOM 7 validator, a GEDCOM 5.5 converter, a GEDZIP packer, and a JSON name-index exporter, so it can anchor a genealogy build pipeline on its own.
• GedFire runs as an MCP server (gedfire mcp), so agents like Claude Desktop or Claude Code can look up people and records in your GEDCOM, and validate or apply a reviewed changeset, directly in conversation instead of shelling out to the CLI — or start it with --read-only to keep the agent to lookups and previews only.

In other words, use GedFire if you want AI help with your research but final say over your family history.

Installation

Download a release

Download the archive for your platform from GitHub Releases, extract it, and run the binary directly:

.\GedFire.exe help

On Linux and macOS, run ./GedFire help from the extracted directory.

Install as a .NET tool

With the .NET 10 SDK installed:

dotnet tool install -g gedfire
gedfire --version

Demo

The repository includes a fictional Ash family and a proposed set of findings. From the repository root, copy the GEDCOM, dry-run the proposal, apply it, and generate the site:

cp docs/demo/ash-whitfield.ged family.ged
gedfire apply --input family.ged --changes docs/demo/proposed-findings.json --items all --dry-run
gedfire apply --input family.ged --changes docs/demo/proposed-findings.json --items all
gedfire generate --input family.ged --output-dir site --template docs/demo/template.html

The dry run confirms exactly what would be accepted:

validation OK (3 ops, items 1,2)

The real apply reports each approved operation and verifies the written file:

applied: createOrUpdateSource @S00003@: created
applied: createOrUpdateVital DEAT on @I2@: updated (cited @S00003@)
applied: item 1: applied (@I2@ Mercy Whitfield -> cite her death, currently uncited)
...
verify OK: round-trip byte-stable, pointers resolve, deltas {SOUR +1}

Open site/index.html to browse the generated family pages. The input family, records, places, and sources are entirely fictional.

Safety model

• --dry-run validates selected items without touching the GEDCOM.
• You can apply all numbered items or just the ones you accept.
• If any operation fails validation, nothing is written.
• A path-based apply holds an exclusive file lock from its initial read through validation and verified write, preventing two GedFire writers from racing to allocate the same record identity.
• Before creating a person, validation uses the same identity matcher as find_person and rejects a high-confidence duplicate. Creating families, sources, and media does not use person duplicate detection.
• Multiple marriages between the same people are allowed, but creating a second marriage to the same person on the same exact date is rejected.
• After a successful write, the file is reparsed and checked: the round trip must be byte-stable, pointers must resolve, and record counts must change by exactly the expected amounts.
• GedFire works on local files and sends no family data or telemetry anywhere.

How changesets work

Suppose an agent finds a death certificate for Mercy Whitfield, whose death is already recorded but uncited. Instead of editing the GEDCOM, the agent proposes a source and a numbered claim in JSON:

{
  "proposal": "mercy-whitfield-death-record",
  "newSources": [
    { "xref": "@NewSource1@", "ops": [
      { "op": "createOrUpdateSource", "xref": "@NewSource1@",
        "auth": "New Hampshire Bureau of Vital Records (fictional)",
        "title": "Death certificate, Mercy (Whitfield) Ash, 1870",
        "accessed": "2026-07-22" } ] }
  ],
  "items": [
    { "item": 1,
      "target": "@I2@ Mercy Whitfield -> cite her death, currently uncited",
      "ops": [
        { "op": "createOrUpdateVital", "record": "@I2@", "fact": "DEAT",
          "value": { "date": "19 JAN 1870", "place": "Salisbury, Hartwell County, New Hampshire" },
          "citation": { "source": "@NewSource1@", "page": "cert. 1870-0114",
                        "dataText": "Mercy Ash, widow of Nathaniel, died 19 Jan 1870, aged 75",
                        "quay": 2 } } ] }
  ]
}

New records use reserved @New<token>@ placeholders rather than caller-selected GEDCOM xrefs. The token can contain letters, digits, and underscores. Its first creating operation fixes the record kind, and every later use of that placeholder in the changeset resolves to the same real xref. Here, apply allocates @S00003@ for @NewSource1@, creates the source once, and resolves the citation to it. Library callers receive the complete placeholder-to-xref map in ApplyResult.MintedXrefs; the CLI names the minted xrefs in its operation log.

Creating a new person is additionally checked against existing and other planned people using the find_person matcher. A high-confidence match is a validation error, so an already-applied person-creation proposal cannot silently create another copy on retry. Ambiguous candidates do not block a reviewed creation.

The complete demo proposal adds a second item as well. More examples covering relationships, notes, media, deletion, and person merges live in GedCore.Tests/TestData/Changesets.

Date arithmetic

date-calc performs genealogical calendar arithmetic without reading a GEDCOM file:

gedfire date-calc --op normalize --date "11 FEB 1691/2"
gedfire date-calc --op add --date "27 SEP 1777" --age "63y 4m 2d"
gedfire date-calc --op sub --date "29 JAN 1841" --age "63y 4m 2d"
gedfire date-calc --op diff --from "27 SEP 1777" --to "29 JAN 1841"

The commands print 11 FEB 1692, 29 JAN 1841, 27 SEP 1777, and 63y 4m 2d, respectively. Arithmetic requires exact Gregorian dates; qualified, partial, BCE, and non-Gregorian dates are rejected rather than having uncertainty invented or discarded. GEDCOM reading, writing, and HTML generation continue to preserve original date text such as 1860, BEF 1860, and dual dates.

The MCP server exposes the same operations through date_calc. Its operation is normalize, add, sub, or diff; the advertised schema describes which fields each operation requires. For example:

{
  "operation": "diff",
  "from": "27 SEP 1777",
  "to": "29 JAN 1841"
}

The result is { "operation": "diff", "date": null, "age": "63y 4m 2d" }. The other operations return the canonical result in date and set age to null.

Command reference

Run gedfire help for syntax, then gedfire <command> with the options above.

When to use it

Use GedFire if you want an AI agent helping with family history research without handing it the master file, if you need a scriptable GEDCOM validation or publishing pipeline, or if you want your published pages to be reproducible from the GEDCOM itself. It's a data-processing tool — not a graphical family-tree editor, a research provider, or a hosted genealogy service.

Roadmap

• GEDCOM interoperability report — the next patch release will add a read-only gedfire audit command. It will summarize GEDCOM 7 conformance, declared and undeclared extensions, unresolved pointers, and GEDZIP/media sharing readiness so researchers can understand a file before sending it to another tool or collaborator.
• MCP write support — shipped. gedfire mcp now exposes validate_changeset and apply_changeset, extending the MCP server through the same reviewed changeset-and-approval path the CLI's apply/apply --dry-run already enforce, rather than opening a second way to mutate a GEDCOM. Start the server with --read-only to keep apply_changeset disabled for a given run — validate_changeset and every lookup tool stay available either way. describe_changeset_ops ships alongside them so the changeset format itself is discoverable over MCP — no external documentation needed to compose one from scratch.
• Agent skills — companion Claude Code skills for the full research workflow (evidence grading, identity correlation, record harvesting, and driving GedFire safely) are being prepared for publication as a separate repository.
• GedCore library package — publish the parser/apply engine on NuGet for embedding in other .NET projects, if there is interest.

GedFire is newly public — if you're interested in the agent skills, watch or star the repo to follow along.

Building from source

GedFire requires the .NET 10 SDK.

git clone https://github.com/morrillonline/GedFire.git
cd GedFire
dotnet build --nologo
dotnet test --nologo
.\GedFire\bin\Debug\net10.0\GedFire.exe help

The solution contains GedCore (the GEDCOM engine), GedFire (the CLI), and GedCore.Tests (the test suite).

Versions use 4.0.<build>, beginning with 4.0.1. Local builds default to build 1; CI supplies its increasing workflow run number, and release builds take the build number from their v4.0.<build> tag. To reproduce another build locally, pass -p:BuildNumber=<build> to dotnet build, test, or publish.

Standards

GedFire is an independent implementation designed to work with FamilySearch GEDCOM 7, the current GEDCOM specification stewarded by FamilySearch. It is not affiliated with or endorsed by FamilySearch or The Church of Jesus Christ of Latter-day Saints.

For specification questions, proposed standard changes, and registered extensions, see the official GEDCOM repository and GEDCOM registries.

Contributing

Bug reports and pull requests are welcome — edge-case GEDCOM fixtures especially. Please don't include private family data in an issue, fixture, or pull request, and run dotnet test --nologo before opening a PR.

License

GedFire is released under the MIT License.