Set API_KEY in your .env to require an API key for all requests:

API_KEY=your-secret-key

Clients can send the key in any of these headers:

Leave API_KEY empty or unset to allow all requests without authentication.

The health-probe routes (/healthz, /readyz, /livez) are the one exception — they stay reachable without a key so orchestrators can poll them. See 🏥 Performance & Health Probes below.

Set UPLOAD_STRATEGY=S3 and provide:

Credential modes:

• Explicit credentials — Set all three of AWS_ACCESS_KEY, AWS_SECRET_ACCESS_KEY, and AWS_REGION. Recommended for simple setups.

• AWS default credential chain — Leave the credential variables unset and boto3 will automatically discover credentials from the standard chain:

  • AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY environment variables
  • Shared credential / config files (~/.aws/credentials)
  • AWS SSO sessions (aws sso login) — useful for local development
  • IRSA (IAM Roles for Service Accounts) — for AWS EKS deployments
  • ECS container credentials / EC2 instance metadata (IMDSv2)

  In this mode only S3_BUCKET is required; region is resolved automatically.

Set UPLOAD_STRATEGY=GCS and provide:

Mount the credentials file via docker-compose.yml volumes.

Set UPLOAD_STRATEGY=AZURE and provide:

Set UPLOAD_STRATEGY=MINIO and provide:

Make sure the bucket exists and your credentials have PutObject/GetObject permissions.

⚠️ Note: This feature is not yet implemented in the official LibreChat repository. It requires a custom LibreChat build with MCP file artifact support. A test version is available at:

👉 https://github.com/geodanchev/LibreChat/tree/feature/mcp-ms-office-docs-integration

Set UPLOAD_STRATEGY=LIBRECHAT to enable seamless document generation within LibreChat conversations. Documents are uploaded to LibreChat's service endpoint and returned as MCP file artifacts that appear as attachments in the chat UI.

Typical URLs:

• Inside Docker network: http://api:3080/api/service/files
• Local development: http://localhost:3080/api/service/files

Generate a service token:

openssl rand -hex 32

LibreChat librechat.yaml configuration:

mcpServers:
  Office-documents:
    type: streamable-http
    url: http://mcp-office-docs:8958/mcp
    headers:
      X-User-Id: "{{LIBRECHAT_USER_ID}}"
      X-User-Email: "{{LIBRECHAT_USER_EMAIL}}"

The X-User-Id and X-User-Email headers are automatically populated by LibreChat and used to associate uploaded files with the correct user.

The server exposes health-check endpoints that Kubernetes (or any orchestrator) can use for startup/readiness/liveness probes. Each returns 200 with a short plain-text body:

These three routes are not protected by API_KEY. They are registered at the Starlette layer (via FastMCP's @custom_route), so they sit outside the MCP middleware stack and deliberately bypass the API-key check described under 🔐 Authentication above — this lets kubelet poll them without credentials. They expose no data beyond the static strings above.

Use HTTP probes rather than TCP ones: a TCP probe only proves the socket still accepts connections, so a wedged Python process with a bound listener would never be restarted. An HTTP probe forces the application itself to answer.

Thread-pool offloading: By default (RUN_BLOCKING_BY_ASYNCIO_THREAD_ENABLED=true), all blocking document-generation work is dispatched to a bounded thread pool (RUN_BLOCKING_MAX_WORKERS threads, default 4). This keeps the asyncio event loop free to respond to health probes and handle concurrent requests — critical for Kubernetes deployments where blocked probes lead to pod restarts.

Set RUN_BLOCKING_BY_ASYNCIO_THREAD_ENABLED=false only for local debugging or to rule out threading-related issues.

Tool parameters (create_powerpoint_presentation):

Every slide takes type plus optional title, notes (speaker notes) and layout.

Sections. Every section slide also starts a section in PowerPoint's outline pane and slide sorter, so the presenter sees the deck's structure rather than a flat list. Slides before the first section slide go in a "Default Section", as PowerPoint would name it.

Blank slides are the escape hatch for the one layout no typed slide fits. Elements draw in order, so a later one sits on top; a text element takes the same inline markdown as a bullet, a shape is one of rectangle, rounded_rectangle, ellipse, chevron, arrow with an optional fill and centred text, and an image keeps its aspect ratio within its box. Anything that would run past the slide edge is shrunk to fit and reported in warnings; anything starting off the slide is skipped and reported.

Body text. body takes either a Markdown bullet string or explicit bullet objects. Prefer the string:

{"type": "content", "title": "Q3 results",
 "body": "- Revenue **up 12%**\n  - EMEA +18%\n  - APAC +4%\n- Churn flat"}

Indent child items with any consistent unit — two spaces, four spaces or a tab. A line without a - marker becomes a top-level bullet. The explicit form is [{"text": "…", "level": 2}], where level is 1 (outermost) to 5.

Inline formatting works in every text field, table cells included: **bold**, *italic*, ***bold italic***, ~~strikethrough~~, __underline__, `code`, ^superscript^, ~subscript~, and [links](https://example.com). The same grammar drives the Word tool, so text formats identically in both. A marker only formats when it hugs its text (**bold**, not ** bold **), so prose like 5 * 3 * 2 = 30 is left alone. Escape a literal marker with \*, or wrap it in backticks.

Tables take raw values — numbers and null are fine, not just strings:

{"type": "kpi", "title": "At a glance",
 "items": [{"value": "€4.2M", "label": "ARR", "delta": "+12% vs Q2"},
           {"value": "18%", "label": "Churn"}]}

{"type": "table", "title": "Pricing",
 "rows": [["Plan", "Users", "Price"], ["Basic", 5, 9.0], ["Pro", 25, 29.0]],
 "align": ["left", "right", "right"], "header_color": "accent1"}

Colours accept 6-digit hex with or without #, or a theme name (accent1…accent6, dark1, dark2, light1, light2). Prefer a theme name so the deck follows your template's palette.

Images take an https URL or an inline data URI, so an image you already hold can be placed without publishing it first:

{"type": "image", "source": "data:image/png;base64,iVBORw0KGgo…", "caption": "Fig 1"}

Warnings. When the deck is produced but not exactly as asked — an image that would not load, body text shrunk to fit, a footer dropped because the layout has no placeholder — the result carries a warnings list alongside the file instead of leaving it in the server log:

{"file": "https://…/deck.pptx", "slide_count": 12,
 "warnings": ["slide 4: body text is about 1.9x the space available and will be shrunk to fit; consider splitting it across slides."]}

Compatibility. The previous key names (slide_type, slide_title, slide_text, indentation_level, speaker_notes, table_data, alternate_rows, image_url, image_caption, quote_text, quote_author, left_column, right_column, chart_data, has_legend, legend_position) are still accepted and mapped onto the current ones, with a note in the log. They will be removed in a future release.

Clients that cannot send objects. slides is published as one flat object schema — every field of every slide type in a single properties map, each saying which types accept it — rather than as a oneOf union of the fourteen types. A union is the better model but not a portable declaration: clients that bridge MCP to a provider without oneOf/$ref drop what they cannot express, show the model slides: array of string, and then reject the call against the union they kept, so every call fails with a schema error no matter what the model sends. Validation is unchanged — it runs on this server, against the union, and names the slide and field it rejected.

As a last resort a slide sent as a string is read rather than refused: a JSON object is the slide it encodes, and anything else is markdown for one slide (# Heading plus text is a title slide, otherwise a content slide with the rest as its body). The whole deck arriving as one JSON string is unpacked the same way. A string that starts like JSON but does not parse is reported instead — a deck truncated in transit must not quietly arrive as one slide titled with the raw JSON. This fallback covers titles and bullets only — send slide objects for everything else.

Tool parameters (create_word_from_markdown):

Block elements (each on its own line, separated by blank lines):

⚠️ Don't confuse --- (page break) with *** (horizontal line).

💡 Numbered paragraphs of a filing keep counting across the section titles, evidence notes and exhibit lists between them — write 3., 4., … and they render as one numbered list, not as paragraphs with typed-in numbers.

💡 A single numbered line is only treated as a list when it starts at 1., continues the count of an earlier list, or is followed by another item. This means a standalone date like 23. června 2026 renders as plain text, not a list. Two cases stay ambiguous and need the dot escaped to render as text: a day-1 date (1. června 2026), which is indistinguishable from a one-item list, and a date whose day happens to be the next number in a running count (3. září 2026 right after item 2.) — write them as 1\. června 2026 / 3\. září 2026.

Inline formatting (works in paragraphs, headings, list items, table cells, quotes):

Nesting and combinations work, e.g. **bold with *italic* inside**, **~~bold strikethrough~~**.

Table features — place the directive on the line directly above the table:

Text alignment (HTML tags, single- or multi-line):

<center>centered text</center>
<div align="right">right-aligned</div>
<div align="justify">justified paragraph…</div>

Soft line break: end a line with two trailing spaces to break within the same paragraph.

Custom styles (issue #66) — remap built-in styles or apply an ad-hoc one:

<!-- style: Callout -->
This paragraph uses the "Callout" style from your template.

The <!-- style: Name --> directive applies a style to the next block only — one paragraph, one heading, the whole table, or the top-level items of a list (nested items keep the List Bullet 2/3 / List Number 2/3 styles). On a numbered list the style's own numbering is used: the list restarts at 1. with the style's numeral format and indents. The directive must be alone on its line, and the name must match the Word style name exactly. Unknown styles fall back to the default with a warning. To remap styles globally or per template, see Custom Templates.

Tool parameters (create_excel_from_markdown):

Sheets & tables:

Formulas & references (put a formul