CalDAV calendars

io.github.ni-c/caldav-mcpv0.1.5Calendar & Time

Read and write CalDAV calendars: events, tasks and journal entries over the open standard

The current version, v0.1.5, was published to the official MCP registry on 2026-10-13. It is distributed as @ni-c/caldav-mcp on npm and as the Docker image ghcr.io/ni-c/caldav-mcp:0.1.5, filed under Calendar & Time by this index, and declares 14 environment variables. Removals and unreachable sources are measured across every server this index tracks, contract drift across the servers that answer in consecutive snapshots; the index's current counts put this record in context.

In-path gate · all MCP tools

Using CalDAV calendars in Claude, Cursor, Gemini CLI, Cline, or Zed?

MCP tool contracts can change remotely with no version bump. The mcpindex gate pins each contract and HOLDs the call when it drifts-before your agent acts. Zero credentials. This is not the package install for this server itself (use Install this server for that).

Install the mcpindex gate (one command)

Rewrites your MCP host config so each server launches behind the gate. Inspect first: curl -fsSL https://mcpindex.ai/install.sh | less

uv tool install mcpindex-gate && mcpindex-config-wire

Auditable install path →Watch it hold a drift →

Trust verdict · v1 advisory · method

REVIEWstatus: PARTIALfresh until 2026-11-06 01:59 UTC

screened 2026-09-06tier: scannedgranularity: description-levelsource: registry

Semantic screen found no manipulation pattern in the description. Conformance probe not yet run.

mcpindex.integrity.descriptionpassINFO

evidence“Normal capability description”via static_description

Limits of this verdict

- Semantic screen only - the deterministic conformance probe has not run on this server
- Confidence is reported but not yet calibrated (v1)
- Screen reads the tool description, not the live behavior
- advisory
- registry description only no input schema
- screen model 8b
- Still current: the description we screened is unchanged, re-checked against the registry
- The registry listing (version, packages, links) changed after this screen ran - the description we assessed did not

Semantic screen: an LLM judge reads the tool description for hidden instructions (status PARTIAL). A pass means the description is not lying, not that the tool is safe: a high-capability tool with an honest description still warrants caution. The deterministic conformance probe has not been run on this server yet, so the screen here is semantic-only. Posture: advisory. Confidences are reported but not yet calibrated (calibrated=false at v1). Full verdict history is not shown on this page.

Own this server? Test a description on the public screen → It is a separate check from the verdict above, so the two can differ.

That verdict was true at screening time (snapshot 2026-10-30).

Contracts can change after screening, with no version bump. The gate pins CalDAV calendars’s tool contracts on first sight and holds any silent change before your agent acts - the check that keeps being true on Tuesday.

See your first HOLD in 2 minutes →

Cite this record

People vet a server before wiring it in. One line on your project site or docs answers that with an independent record: screening verdict, registry provenance, contract drift history. It stays current as new screens and drift events land.

Markdown

[Independent trust record for CalDAV calendars](https://mcpindex.ai/server/io-github-ni-c-caldav-mcp) - screening verdict, registry provenance, and contract drift monitoring.

HTML

<a href="https://mcpindex.ai/server/io-github-ni-c-caldav-mcp">Independent trust record for CalDAV calendars</a> - screening verdict, registry provenance, and contract drift monitoring.

Embed this badge

A live verdict badge for your README or listing. It reflects the current screen, links back here, and updates when the verdict does.

Markdown

[![mcpindex](https://mcpindex.ai/api/v1/badge/io-github-ni-c-caldav-mcp)](https://mcpindex.ai/server/io-github-ni-c-caldav-mcp)

HTML

<a href="https://mcpindex.ai/server/io-github-ni-c-caldav-mcp"><img src="https://mcpindex.ai/api/v1/badge/io-github-ni-c-caldav-mcp" alt="mcpindex verdict" height="20" /></a>

Environment variables

CALDAV_URL

required

Root of the CalDAV server, e.g. https://dav.example.net. A calendar collection URL also works.

CALDAV_USERNAME

Account name. Most hosted services want an app-specific password with it.

CALDAV_PASSWORD

secret

Password or app-specific password. Deleted from the environment once read.

CALDAV_TOKEN

secret

Bearer token, as an alternative to username and password. Not both.

CALDAV_CALENDARS

Comma-separated calendars this server may touch, by path or final path segment. Default: all of them.

CALDAV_TIMEZONE

IANA zone for timestamps that carry no offset, e.g. Europe/Berlin (default: UTC)

CALDAV_USER_EMAIL

The address you are invited as, so respond_to_event can find your own attendee line

CALDAV_MAX_EVENTS

Entries a listing returns by default, 1 to 500 (default: 100)

CALDAV_READ_ONLY

Set to true to register only the read tools (default: false)

CALDAV_INSECURE_TLS

Set to true to accept a self-signed certificate on the configured host only (default: false)

CALDAV_ALLOW_PLAINTEXT

Set to true to allow a plain http:// URL to a host that is not loopback, which sends the credentials unencrypted (default: false)

CALDAV_ALLOW_TOOLS

Comma-separated tool names or list_* prefixes to register; 'essential' selects a curated preset (default: all tools)

CALDAV_DENY_TOOLS

Comma-separated tool names or list_* prefixes to remove from whatever the allow list left

ELICITATION

Deliberately unprefixed, and reaches every MCP server in the environment. Set to false to make guarded tools use the two-call token instead of a dialog (default: true)

CALDAV_URL

required

Root of the CalDAV server, e.g. https://dav.example.net. A calendar collection URL also works.

CALDAV_USERNAME

Account name. Most hosted services want an app-specific password with it.

CALDAV_PASSWORD

secret

Password or app-specific password. Deleted from the environment once read.

CALDAV_TOKEN

secret

Bearer token, as an alternative to username and password. Not both.

CALDAV_CALENDARS

Comma-separated calendars this server may touch, by path or final path segment. Default: all of them.

CALDAV_TIMEZONE

IANA zone for timestamps that carry no offset, e.g. Europe/Berlin (default: UTC)

CALDAV_USER_EMAIL

The address you are invited as, so respond_to_event can find your own attendee line

CALDAV_MAX_EVENTS

Entries a listing returns by default, 1 to 500 (default: 100)

CALDAV_READ_ONLY

Set to true to register only the read tools (default: false)

CALDAV_INSECURE_TLS

Set to true to accept a self-signed certificate on the configured host only (default: false)

CALDAV_ALLOW_PLAINTEXT

Set to true to allow a plain http:// URL to a host that is not loopback, which sends the credentials unencrypted (default: false)

CALDAV_ALLOW_TOOLS

Comma-separated tool names or list_* prefixes to register; 'essential' selects a curated preset (default: all tools)

CALDAV_DENY_TOOLS

Comma-separated tool names or list_* prefixes to remove from whatever the allow list left

ELICITATION

Deliberately unprefixed, and reaches every MCP server in the environment. Set to false to make guarded tools use the two-call token instead of a dialog (default: true)

MCP quality score · maturity, not trust · methodology

freshness

completeness

installability

documentation

stability

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Install this server

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "caldav-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "--",
        "@ni-c/caldav-mcp"
      ],
      "env": {
        "CALDAV_URL": "<caldav_url>",
        "CALDAV_USERNAME": "<caldav_username>",
        "CALDAV_PASSWORD": "<your-caldav_password>",
        "CALDAV_TOKEN": "<your-caldav_token>",
        "CALDAV_CALENDARS": "<caldav_calendars>",
        "CALDAV_TIMEZONE": "<caldav_timezone>",
        "CALDAV_USER_EMAIL": "<caldav_user_email>",
        "CALDAV_MAX_EVENTS": "<caldav_max_events>",
        "CALDAV_READ_ONLY": "<caldav_read_only>",
        "CALDAV_INSECURE_TLS": "<caldav_insecure_tls>",
        "CALDAV_ALLOW_PLAINTEXT": "<caldav_allow_plaintext>",
        "CALDAV_ALLOW_TOOLS": "<caldav_allow_tools>",
        "CALDAV_DENY_TOOLS": "<caldav_deny_tools>",
        "ELICITATION": "<elicitation>"
      }
    }
  }
}

Cursor (.cursor/mcp.json)

{
  "mcpServers": {
    "caldav-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "--",
        "@ni-c/caldav-mcp"
      ],
      "env": {
        "CALDAV_URL": "<caldav_url>",
        "CALDAV_USERNAME": "<caldav_username>",
        "CALDAV_PASSWORD": "<your-caldav_password>",
        "CALDAV_TOKEN": "<your-caldav_token>",
        "CALDAV_CALENDARS": "<caldav_calendars>",
        "CALDAV_TIMEZONE": "<caldav_timezone>",
        "CALDAV_USER_EMAIL": "<caldav_user_email>",
        "CALDAV_MAX_EVENTS": "<caldav_max_events>",
        "CALDAV_READ_ONLY": "<caldav_read_only>",
        "CALDAV_INSECURE_TLS": "<caldav_insecure_tls>",
        "CALDAV_ALLOW_PLAINTEXT": "<caldav_allow_plaintext>",
        "CALDAV_ALLOW_TOOLS": "<caldav_allow_tools>",
        "CALDAV_DENY_TOOLS": "<caldav_deny_tools>",
        "ELICITATION": "<elicitation>"
      }
    }
  }
}

Cline (cline_mcp_settings.json)

{
  "mcpServers": {
    "caldav-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "--",
        "@ni-c/caldav-mcp"
      ],
      "env": {
        "CALDAV_URL": "<caldav_url>",
        "CALDAV_USERNAME": "<caldav_username>",
        "CALDAV_PASSWORD": "<your-caldav_password>",
        "CALDAV_TOKEN": "<your-caldav_token>",
        "CALDAV_CALENDARS": "<caldav_calendars>",
        "CALDAV_TIMEZONE": "<caldav_timezone>",
        "CALDAV_USER_EMAIL": "<caldav_user_email>",
        "CALDAV_MAX_EVENTS": "<caldav_max_events>",
        "CALDAV_READ_ONLY": "<caldav_read_only>",
        "CALDAV_INSECURE_TLS": "<caldav_insecure_tls>",
        "CALDAV_ALLOW_PLAINTEXT": "<caldav_allow_plaintext>",
        "CALDAV_ALLOW_TOOLS": "<caldav_allow_tools>",
        "CALDAV_DENY_TOOLS": "<caldav_deny_tools>",
        "ELICITATION": "<elicitation>"
      }
    }
  }
}

Zed (~/.config/zed/settings.json)

Merge into the context_servers block of your Zed settings.

{
  "context_servers": {
    "caldav-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "--",
        "@ni-c/caldav-mcp"
      ],
      "env": {
        "CALDAV_URL": "<caldav_url>",
        "CALDAV_USERNAME": "<caldav_username>",
        "CALDAV_PASSWORD": "<your-caldav_password>",
        "CALDAV_TOKEN": "<your-caldav_token>",
        "CALDAV_CALENDARS": "<caldav_calendars>",
        "CALDAV_TIMEZONE": "<caldav_timezone>",
        "CALDAV_USER_EMAIL": "<caldav_user_email>",
        "CALDAV_MAX_EVENTS": "<caldav_max_events>",
        "CALDAV_READ_ONLY": "<caldav_read_only>",
        "CALDAV_INSECURE_TLS": "<caldav_insecure_tls>",
        "CALDAV_ALLOW_PLAINTEXT": "<caldav_allow_plaintext>",
        "CALDAV_ALLOW_TOOLS": "<caldav_allow_tools>",
        "CALDAV_DENY_TOOLS": "<caldav_deny_tools>",
        "ELICITATION": "<elicitation>"
      }
    }
  }
}

Claude Code (claude mcp add)

claude mcp add --scope user caldav-mcp -- npx -y -- @ni-c/caldav-mcp

Gemini CLI (gemini mcp add)

gemini mcp add -s user caldav-mcp npx -y -- @ni-c/caldav-mcp

Claude Desktop (Docker)

{
  "mcpServers": {
    "caldav-mcp": {
      "command": "docker",
      "args": [
        "run",
        "--rm",
        "-i",
        "--",
        "ghcr.io/ni-c/caldav-mcp:0.1.5"
      ],
      "env": {
        "CALDAV_URL": "<caldav_url>",
        "CALDAV_USERNAME": "<caldav_username>",
        "CALDAV_PASSWORD": "<your-caldav_password>",
        "CALDAV_TOKEN": "<your-caldav_token>",
        "CALDAV_CALENDARS": "<caldav_calendars>",
        "CALDAV_TIMEZONE": "<caldav_timezone>",
        "CALDAV_USER_EMAIL": "<caldav_user_email>",
        "CALDAV_MAX_EVENTS": "<caldav_max_events>",
        "CALDAV_READ_ONLY": "<caldav_read_only>",
        "CALDAV_INSECURE_TLS": "<caldav_insecure_tls>",
        "CALDAV_ALLOW_PLAINTEXT": "<caldav_allow_plaintext>",
        "CALDAV_ALLOW_TOOLS": "<caldav_allow_tools>",
        "CALDAV_DENY_TOOLS": "<caldav_deny_tools>",
        "ELICITATION": "<elicitation>"
      }
    }
  }
}

Verdict API

curl -s mcpindex.ai/api/v1/trust/server/io-github-ni-c-caldav-mcp

Free-tier verdict as JSON: decision + dimensions + severity. Call it from your agent before it invokes a tool it just discovered.

Details

version: v0.1.5
category: Calendar & Time
verdict expires: 2026-11-06
quality: 90 / 100
operator: ni-c

Listing

Listed from the official MCP registry. Unclaimed by its maintainer. Maintainer? Email us →

Provenance

Each verdict is bound to a hash of the exact description it judged, so a re-crawl that changes the text produces a new record rather than silently inheriting this one. Verdict history is hash-chained and anchored to Bitcoin via OpenTimestamps (latest confirmed at block 973,647). Verify it yourself.

Links

Repository →Website →