WeCom (Enterprise WeChat)

Connect Hermes to WeCom (企业微信), Tencent's enterprise messaging platform. The adapter uses WeCom's AI Bot WebSocket gateway for real-time bidirectional communication — no public endpoint or webhook needed.

Prerequisites

• A WeCom organization account
• An AI Bot created in the WeCom Admin Console
• The Bot ID and Secret from the bot's credentials page
• Python packages: aiohttp and httpx

Setup

1. Create an AI Bot

1. Log in to the WeCom Admin Console
2. Navigate to Applications → Create Application → AI Bot
3. Configure the bot name and description
4. Copy the Bot ID and Secret from the credentials page

2. Configure Hermes

Run the interactive setup:

hermes gateway setup

Select WeCom and enter your Bot ID and Secret.

Or set environment variables in ~/.hermes/.env:

WECOM_BOT_ID=your-bot-id
WECOM_SECRET=your-secret

# Optional: restrict access
WECOM_ALLOWED_USERS=user_id_1,user_id_2

# Optional: home channel for cron/notifications
WECOM_HOME_CHANNEL=chat_id

3. Start the gateway

hermes gateway start

Features

• WebSocket transport — persistent connection, no public endpoint needed
• DM and group messaging — configurable access policies
• Per-group sender allowlists — fine-grained control over who can interact in each group
• Media support — images, files, voice, video upload and download
• AES-encrypted media — automatic decryption for inbound attachments
• Quote context — preserves reply threading
• Markdown rendering — rich text responses
• Reply-mode streaming — correlates responses to inbound message context
• Auto-reconnect — exponential backoff on connection drops

Configuration Options

Set these in config.yaml under platforms.wecom.extra:

Key	Default	Description
bot_id	—	WeCom AI Bot ID (required)
secret	—	WeCom AI Bot Secret (required)
websocket_url	wss://openws.work.weixin.qq.com	WebSocket gateway URL
dm_policy	open	DM access: open, allowlist, disabled, pairing
group_policy	open	Group access: open, allowlist, disabled
allow_from	[]	User IDs allowed for DMs (when dm_policy=allowlist)
group_allow_from	[]	Group IDs allowed (when group_policy=allowlist)
groups	{}	Per-group configuration (see below)

Access Policies

DM Policy

Controls who can send direct messages to the bot:

Value	Behavior
open	Anyone can DM the bot (default)
allowlist	Only user IDs in allow_from can DM
disabled	All DMs are ignored
pairing	Pairing mode (for initial setup)

WECOM_DM_POLICY=allowlist

Group Policy

Controls which groups the bot responds in:

Value	Behavior
open	Bot responds in all groups (default)
allowlist	Bot only responds in group IDs listed in group_allow_from
disabled	All group messages are ignored

WECOM_GROUP_POLICY=allowlist

Per-Group Sender Allowlists

For fine-grained control, you can restrict which users are allowed to interact with the bot within specific groups. This is configured in config.yaml:

platforms:
  wecom:
    enabled: true
    extra:
      bot_id: "your-bot-id"
      secret: "your-secret"
      group_policy: "allowlist"
      group_allow_from:
        - "group_id_1"
        - "group_id_2"
      groups:
        group_id_1:
          allow_from:
            - "user_alice"
            - "user_bob"
        group_id_2:
          allow_from:
            - "user_charlie"
        "*":
          allow_from:
            - "user_admin"

How it works:

1. The group_policy and group_allow_from controls determine whether a group is allowed at all.
2. If a group passes the top-level check, the groups.<group_id>.allow_from list (if present) further restricts which senders within that group can interact with the bot.
3. A wildcard "*" group entry serves as a default for groups not explicitly listed.
4. Allowlist entries support the * wildcard to allow all users, and entries are case-insensitive.
5. Entries can optionally use the wecom:user: or wecom:group: prefix format — the prefix is stripped automatically.

If no allow_from is configured for a group, all users in that group are allowed (assuming the group itself passes the top-level policy check).

Media Support

Inbound (receiving)

The adapter receives media attachments from users and caches them locally for agent processing:

Type	How it's handled
Images	Downloaded and cached locally. Supports both URL-based and base64-encoded images.
Files	Downloaded and cached. Filename is preserved from the original message.
Voice	Voice message text transcription is extracted if available.
Mixed messages	WeCom mixed-type messages (text + images) are parsed and all components extracted.

Quoted messages: Media from quoted (replied-to) messages is also extracted, so the agent has context about what the user is replying to.

AES-Encrypted Media Decryption

WeCom encrypts some inbound media attachments with AES-256-CBC. The adapter handles this automatically:

• When an inbound media item includes an aeskey field, the adapter downloads the encrypted bytes and decrypts them using AES-256-CBC with PKCS#7 padding.
• The AES key is the base64-decoded value of the aeskey field (must be exactly 32 bytes).
• The IV is derived from the first 16 bytes of the key.
• This requires the cryptography Python package (pip install cryptography).

No configuration is needed — decryption happens transparently when encrypted media is received.

Outbound (sending)

Method	What it sends	Size limit
send	Markdown text messages	4000 chars
send_image / send_image_file	Native image messages	10 MB
send_document	File attachments	20 MB
send_voice	Voice messages (AMR format only for native voice)	2 MB
send_video	Video messages	10 MB

Chunked upload: Files are uploaded in 512 KB chunks through a three-step protocol (init → chunks → finish). The adapter handles this automatically.

Automatic downgrade: When media exceeds the native type's size limit but is under the absolute 20 MB file limit, it is automatically sent as a generic file attachment instead:

• Images > 10 MB → sent as file
• Videos > 10 MB → sent as file
• Voice > 2 MB → sent as file
• Non-AMR audio → sent as file (WeCom only supports AMR for native voice)

Files exceeding the absolute 20 MB limit are rejected with an informational message sent to the chat.

Reply-Mode Stream Responses

When the bot receives a message via the WeCom callback, the adapter remembers the inbound request ID. If a response is sent while the request context is still active, the adapter uses WeCom's reply-mode (aibot_respond_msg) with streaming to correlate the response directly to the inbound message. This provides a more natural conversation experience in the WeCom client.

If the inbound request context has expired or is unavailable, the adapter falls back to proactive message sending via aibot_send_msg.

Reply-mode also works for media: uploaded media can be sent as a reply to the originating message.

Connection and Reconnection

The adapter maintains a persistent WebSocket connection to WeCom's gateway at wss://openws.work.weixin.qq.com.

Connection Lifecycle

1. Connect: Opens a WebSocket connection and sends an aibot_subscribe authentication frame with the bot_id and secret.
2. Heartbeat: Sends application-level ping frames every 30 seconds to keep the connection alive.
3. Listen: Continuously reads inbound frames and dispatches message callbacks.

Reconnection Behavior

On connection loss, the adapter uses exponential backoff to reconnect:

Attempt	Delay
1st retry	2 seconds
2nd retry	5 seconds
3rd retry	10 seconds
4th retry	30 seconds
5th+ retry	60 seconds

After each successful reconnection, the backoff counter resets to zero. All pending request futures are failed on disconnect so callers don't hang indefinitely.

Deduplication

Inbound messages are deduplicated using message IDs with a 5-minute window and a maximum cache of 1000 entries. This prevents double-processing of messages during reconnection or network hiccups.

All Environment Variables

Variable	Required	Default	Description
WECOM_BOT_ID	✅	—	WeCom AI Bot ID
WECOM_SECRET	✅	—	WeCom AI Bot Secret
WECOM_ALLOWED_USERS	—	(empty)	Comma-separated user IDs for the gateway-level allowlist
WECOM_HOME_CHANNEL	—	—	Chat ID for cron/notification output
WECOM_WEBSOCKET_URL	—	wss://openws.work.weixin.qq.com	WebSocket gateway URL
WECOM_DM_POLICY	—	open	DM access policy
WECOM_GROUP_POLICY	—	open	Group access policy

Troubleshooting

Problem	Fix
WECOM_BOT_ID and WECOM_SECRET are required	Set both env vars or configure in setup wizard
WeCom startup failed: aiohttp not installed	Install aiohttp: pip install aiohttp
WeCom startup failed: httpx not installed	Install httpx: pip install httpx
invalid secret (errcode=40013)	Verify the secret matches your bot's credentials
Timed out waiting for subscribe acknowledgement	Check network connectivity to openws.work.weixin.qq.com
Bot doesn't respond in groups	Check group_policy setting and ensure the group ID is in group_allow_from
Bot ignores certain users in a group	Check per-group allow_from lists in the groups config section
Media decryption fails	Install cryptography: pip install cryptography
cryptography is required for WeCom media decryption	The inbound media is AES-encrypted. Install: pip install cryptography
Voice messages sent as files	WeCom only supports AMR format for native voice. Other formats are auto-downgraded to file.
File too large error	WeCom has a 20 MB absolute limit on all file uploads. Compress or split the file.
Images sent as files	Images > 10 MB exceed the native image limit and are auto-downgraded to file attachments.
Timeout sending message to WeCom	The WebSocket may have disconnected. Check logs for reconnection messages.
WeCom websocket closed during authentication	Network issue or incorrect credentials. Verify bot_id and secret.