# io.github.syncday-app/sync-day (remote · sync.day)

Free no-signup group scheduling; share a link and rank times by who's free.

- Trust score: 79/100 (medium)
- Change this week: 0
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- remote · `sync.day`: 79/100 (this document), [markdown](https://verifymcp.io/servers/syncday-app-sync-day/sync.md), [page](https://verifymcp.io/servers/syncday-app-sync-day/sync)

## Channel facts

- Endpoint: `https://sync.day/mcp/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (remove_participant).
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 66/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 2091 tokens (~261/item across 8 items; 8 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 100/100
  - No destabilizing schema changes in the last 30 days.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - All 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.
  - An AI judge read all 9 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the io.github.syncday-app/sync-day MCP server?

io.github.syncday-app/sync-day is a hosted endpoint at https://sync.day/mcp/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http syncday-app-sync-day 'https://sync.day/mcp/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "syncday-app-sync-day": {
      "url": "https://sync.day/mcp/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "syncday-app-sync-day": {
      "type": "http",
      "url": "https://sync.day/mcp/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.syncday-app-sync-day]
url = "https://sync.day/mcp/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "syncday-app-sync-day": {
      "type": "remote",
      "url": "https://sync.day/mcp/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add syncday-app-sync-day --url 'https://sync.day/mcp/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  syncday-app-sync-day:
    url: "https://sync.day/mcp/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "syncday-app-sync-day": {
      "Transport": "http",
      "Url": "https://sync.day/mcp/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add syncday-app-sync-day -t streamable-http -u 'https://sync.day/mcp/mcp'
```

### Other

```json
{
  "mcpServers": {
    "syncday-app-sync-day": {
      "type": "http",
      "url": "https://sync.day/mcp/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-10-07 (score 79, 0)

- [security] Stability: 0.97 → pass

### 2026-10-04 (score 79, +1)

No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-28 (score 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-25 (score 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-06 (score 0)

- [functional improvement] Stability: unverified → 0.03

### 2026-09-05 (score 0)

First indexed and scored.

## MCP tools (8)

### `create_event` (~409 tokens)

Create event

Create a sync.day availability poll and get its share link. Candidate days run from startDate to endDate (inclusive; or give days instead). Each day offers candidate START times from hourFrom, every startStepMinutes, as long as start + durationMinutes <= hourTo. Returns slug, public url (share this), adminUrl and adminKey (keep private; needed for update_event / remove_participant). Example: 周六周日下午聚餐 3 小时 -> {title:'周末聚餐', startDate:'2026-09-05', endDate:'2026-09-06', hourFrom:13, hourTo:18, durationMinutes:180, startStepMinutes:60}.

Input parameters:

- `days` (integer): Number of consecutive days from startDate (1-21); alternative to endDate.
- `durationMinutes` (required): Event length in minutes. One of 30, 60, 90, 120, 180, 240, 480.
- `endDate` (string): Last candidate day, inclusive, YYYY-MM-DD (same as startDate for a single day; at most 21 days). Give this or days; endDate wins when both are set.
- `hourFrom` (integer, required): Earliest hour of each day (0-23). e.g. 9
- `hourTo` (integer, required): End of each day's window, exclusive (1-24), must be > hourFrom. e.g. 22
- `question` (string): Optional prompt shown to participants, max 200 chars. e.g. 哪天晚上有空？
- `startDate` (string, required): First candidate day, YYYY-MM-DD. e.g. 2026-09-05
- `startStepMinutes`: Gap between candidate start times in minutes: 30 or 60 (default 60).
- `title` (string, required): Event name, max 60 chars. e.g. 周末聚餐, Team sync

### `parse_event_text` (~109 tokens)

Parse event text

Turn a natural-language sentence (Chinese works best) into create_event input using sync.day's AI parser. Does NOT create anything; review the result, then call create_event. Example: '下周六或周日下午聚餐，大概 3 小时'.

Input parameters:

- `text` (string, required): One sentence describing the event, max 300 chars.
- `today` (string): Reference date for relative words like 明天/下周, YYYY-MM-DD. Defaults to today in Asia/Shanghai.

### `get_event` (~114 tokens)

Get event

Read an event: settings, every candidate start key per day (startOptions), who has answered (participants with their start keys; names may repeat), the top 10 start times by head-count (ranked), the starts EVERYONE with picks can make with their votes (voteOptions), each person's vote (votes) and decidedStart. No key needed.

Input parameters:

- `slug` (string, required): Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821)

### `submit_availability` (~267 tokens)

Submit availability

Save (or replace) one person's availability: the candidate start keys they can make, from get_event.startOptions. The person is identified by `identity`, not by name: the same identity later overwrites the same row (and can rename it), a different identity with the same name is a second participant. Keys outside the event's start options are rejected. Returns the updated ranking.

Input parameters:

- `identity` (string, required): Random secret for this person that you generate and keep per person, 16-256 chars (e.g. 32 hex chars; NOT a plain user id or name, since anyone who guesses it can act as them). Same identity = same p…
- `name` (string, required): Display name, 1-20 chars, may repeat. e.g. 小明
- `slug` (string, required): Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821)
- `starts` (array, required): Start keys like 2026-09-05T14:00. Empty array clears this person's picks.

### `remove_participant` (~112 tokens)

Remove participant

Organiser only: remove one participant by name (the oldest row with that name when it repeats), together with their vote. Requires the adminKey from create_event.

Input parameters:

- `adminKey` (string, required): Organiser key returned by create_event (the ?key= part of adminUrl).
- `name` (string, required): Exact participant name to remove.
- `slug` (string, required): Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821)

### `update_event` (~367 tokens)

Update event

Organiser only: change any event settings (same fields and rules as create_event; omitted fields keep their current value; endDate wins over days). Existing picks are kept; those no longer valid starts are just hidden.

Input parameters:

- `adminKey` (string, required): Organiser key returned by create_event (the ?key= part of adminUrl).
- `days` (integer): Number of consecutive days from startDate (1-21); alternative to endDate.
- `durationMinutes`: Event length in minutes. One of 30, 60, 90, 120, 180, 240, 480.
- `endDate` (string): Last candidate day, inclusive, YYYY-MM-DD (same as startDate for a single day; at most 21 days). Give this or days; endDate wins when both are set.
- `hourFrom` (integer): Earliest hour of each day (0-23). e.g. 9
- `hourTo` (integer): End of each day's window, exclusive (1-24), must be > hourFrom. e.g. 22
- `question` (string): Optional prompt shown to participants, max 200 chars. e.g. 哪天晚上有空？
- `slug` (string, required): Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821)
- `startDate` (string): First candidate day, YYYY-MM-DD. e.g. 2026-09-05
- `startStepMinutes`: Gap between candidate start times in minutes: 30 or 60 (default 60).
- `title` (string): Event name, max 60 chars. e.g. 周末聚餐, Team sync

### `vote_time` (~325 tokens)

Approve start times

Approval voting: set every start one person accepts (replaces their earlier approvals; an empty list clears them). The voter is the `identity` used in submit_availability and must have at least one start saved. Only keys listed in get_event.voteOptions are accepted; the error lists the current options otherwise. Rejected once the organiser decided. Example: {slug:'calm-otter-4821', identity:'3f9a1c77b2e04d5e8a61f0c9d2b7e415', starts:['2026-09-05T15:00','2026-09-06T10:00']}. `start` is shorthand for a single-item `starts`.

Input parameters:

- `identity` (string, required): Random secret for this person that you generate and keep per person, 16-256 chars (e.g. 32 hex chars; NOT a plain user id or name, since anyone who guesses it can act as them). Same identity = same p…
- `slug` (string, required): Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821)
- `start` (string): Shorthand for starts: [start]
- `starts` (array): All start keys this person accepts (from get_event.voteOptions); [] clears their approvals

### `decide_time` (~125 tokens)

Decide the time

Organiser only: settle on a start time (locks availability picking and voting; the page shows 已定). Pass start=null to reopen. Requires the adminKey from create_event.

Input parameters:

- `adminKey` (string, required): Organiser key returned by create_event (the ?key= part of adminUrl).
- `slug` (string, required): Event slug from the URL, e.g. calm-otter-4821 (sync.day/calm-otter-4821)
- `start` (required): A candidate start key of the event (normally one of voteOptions), or null to reopen.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/syncday-app-sync-day/sync#diagnostics

## Score history

- 2026-11-05: 79
- 2026-11-04: 79
- 2026-11-03: 79
- 2026-11-02: 79
- 2026-11-01: 79
- 2026-10-31: 79
- 2026-10-30: 79
- 2026-10-29: 79
- 2026-10-28: 79
- 2026-10-27: 79
- 2026-10-26: 79
- 2026-10-25: 79
- 2026-10-24: 79
- 2026-10-23: 79
- 2026-10-22: 79
- 2026-10-21: 79
- 2026-10-20: 79
- 2026-10-19: 79
- 2026-10-18: 79
- 2026-10-17: 79
- 2026-10-16: 79
- 2026-10-15: 79
- 2026-10-14: 79
- 2026-10-13: 79
- 2026-10-12: 79
- 2026-10-10: 79
- 2026-10-07: 79
- 2026-10-04: 79
- 2026-10-03: 78
- 2026-10-02: 78

## Common questions

### What is the io.github.syncday-app/sync-day MCP server?

io.github.syncday-app/sync-day is an MCP server listed in the public MCP registry as io.github.syncday-app/sync-day. Free no-signup group scheduling; share a link and rank times by who's free. This page covers its hosted endpoint (https://sync.day/mcp/mcp).

### Is the io.github.syncday-app/sync-day MCP server safe to use?

io.github.syncday-app/sync-day scores 79 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the io.github.syncday-app/sync-day MCP server expose?

io.github.syncday-app/sync-day exposes 8 tools: create_event, parse_event_text, get_event, submit_availability, remove_participant, and 3 more. Their descriptions and schemas cost roughly 1,828 tokens of context every time the server is loaded.

### Does the io.github.syncday-app/sync-day MCP server require authentication?

No. We connected to io.github.syncday-app/sync-day without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the io.github.syncday-app/sync-day MCP server still maintained?

io.github.syncday-app/sync-day is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://sync.day/mcp/mcp
- Website: https://sync.day/
- Changelog RSS feed: https://verifymcp.io/servers/syncday-app-sync-day/sync.xml
- Changelog JSON feed: https://verifymcp.io/servers/syncday-app-sync-day/sync.json
- HTML version of this page: https://verifymcp.io/servers/syncday-app-sync-day/sync