HiveMCP

Generates and edits PowerPoint, Word and Excel files for OpenWebUI. Runs as a container, exposed both as an MCP Streamable HTTP server and as an OpenAPI tool server from the same FastAPI app.

Why both: OpenWebUI renders inline iframes only for tool results carrying Content-Disposition: inline, and that path exists for OpenAPI tool servers but not for the native MCP surface. MCP gives protocol compatibility, OpenAPI gives the configuration GUI. See docs/IMPLEMENTATION_PLAN.md for the full reasoning and the milestone plan.

Status

Related MCP server: office-mcp-server

Quick start

uv venv && source .venv/bin/activate
uv pip install -e ".[dev]"
cp .env.example .env

pytest
python -m hivemcp          # http://localhost:8080/healthz

Docker

make up      # build, start, wait for healthy
make smoke   # verify it actually works
make logs
make down

make owui additionally starts an OpenWebUI instance on http://localhost:3000, which is what the M0 integration spikes need.

Without make:

docker compose -f deploy/docker-compose.yml up --build -d --wait
./deploy/smoke.sh

Two things the compose file does deliberately:

• Named volume, not a bind mount. The container runs as uid 10001; a host directory would arrive owned by your user and every write would fail with Permission denied.

• HIVE_SIGNING_KEY is fixed. Left unset, each start generates a new key and every download link minted before the restart stops working.

Connecting OpenWebUI

Both surfaces are added under Admin Settings → Integrations → +. Adding MCP servers is admin-only; regular users may only add OpenAPI servers.

Use http://host.docker.internal:8080 instead when OpenWebUI runs in a container and HiveMCP does not. Set Auth to None unless you configured HIVE_AUTH_TOKEN: choosing Bearer without filling in the key sends an empty Authorization header, which most servers reject outright.

Paste this into the connection's Headers field so tool calls carry the caller's identity. OpenWebUI expands the tokens server-side:

{
  "X-Hive-User-Id": "{{USER_ID}}",
  "X-Hive-User-Email": "{{USER_EMAIL}}",
  "X-Hive-Groups": "{{USER_GROUPS}}",
  "X-Hive-Chat-Id": "{{CHAT_ID}}"
}

Both can be registered at once. MCP gives protocol compatibility with other clients; OpenAPI is the surface that can return Rich UI embeds, which the configuration GUI needs in M5.

Layout

hivemcp/
  app.py                  FastAPI factory: health, download, both surfaces
  config.py               HIVE_* settings; refuses to start unauthenticated in prod
  auth.py                 bearer check, identity headers, HMAC-signed UI links
  surfaces/
    mcp_server.py         MCP Streamable HTTP, stateless, mounted at /mcp
    openapi_tools.py      /tools/* with explicit operation ids
  core/
    service.py            shared logic: validation, render semaphore, delivery
    models.py             DeckSpec / DocSpec / SheetSpec / RenderOptions
    delivery.py           signed URL, OpenWebUI upload, composite with fallback
    render/               pptx.py, docx.py, xlsx.py, theme.py
    files/owui_client.py  OpenWebUI Files API
    files/workdir.py      artifact store on the PVC, with TTL sweep
deploy/                   Dockerfile, docker-compose.yml, smoke.sh
docs/IMPLEMENTATION_PLAN.md
tests/

The renderers know nothing about FastAPI or MCP. Both surfaces are thin adapters over core/, which keeps them from drifting apart and makes the interesting logic testable without HTTP.

Design notes worth knowing

Specs are strict. Every model sets extra="forbid". A model that invents a field gets a validation error it can correct on the next turn rather than a silently dropped value and a wrong-looking document.

Untrusted text never becomes an Excel formula. Cell values starting with =, +, - or @ are prefixed with ' unless the column is explicitly typed formula. Spreadsheet content originates from model output and uploaded documents, so this is the formula injection boundary.

Fonts are a name, not a file. OOXML stores only the font name; if the reader's machine lacks it, their viewer substitutes silently. Fonts outside the set that ships with Office produce a warning on the render result.

Page counts are estimates. Word paginates at open time using the installed fonts and printer driver, so no library can know the real count. The result field is called page_estimate for that reason.

Errors name their location. A failure on slide 7 says so, because the model needs to know where to fix the spec, not just what was wrong.

Configuration

See .env.example. Two settings matter more than they look:

• HIVE_SIGNING_KEY — must be set explicitly when running more than one replica. Each pod otherwise generates its own key at start-up, and download links break whenever a request lands on a different pod than the one that signed the link.

• HIVE_ENVIRONMENT=prod — makes the service refuse to start without an auth token and OpenWebUI credentials, rather than coming up silently unauthenticated.