MCP — Slack Server

Enforce Scopebound policies on agents using the Slack MCP server.

Install

pip install scopebound

Role template

from scopebound import ScopeboundSDK
from scopebound.adapters.mcp_slack import SlackMCPAdapter

sb = ScopeboundSDK(base_url="https://your-partner.api.scopebound.ai", api_key="sb-...")

role = SlackMCPAdapter.role_template(
    name="slack-agent",
    allowed_channels=["#engineering", "#alerts", "#scopebound-demo"],
    block_external_dms=True,          # block DMs to users outside your workspace
    approval_required_external=True   # HITL on any send to an external-facing channel
)
sb.create_role(**role)

Integration

from scopebound.adapters.mcp_slack import SlackMCPAdapter

adapter = SlackMCPAdapter(sb, role_id="slack-agent")

@server.pre_call
def enforce(tool_name: str, arguments: dict) -> None:
    adapter.enforce(tool_name, arguments)

Enforced tools

Tool	Default policy	Notes
`list_channels`	Allow	No channel restriction on listing
`send_message`	Allow	Channel must be in `allowed_channels`
`post_to_channel`	Allow	Channel must be in `allowed_channels`
`send_dm`	Deny	Blocked entirely when `block_external_dms=True`

External channel sends

If approval_required_external=True, any post_to_channel or send_message targeting a channel outside your internal whitelist triggers HITL approval before delivery.

Deny codes

Code	Trigger
`SCOPE_VIOLATION`	Tool not in role's `allowed_tools`
`PARAMETER_VIOLATION`	Channel not in `allowed_channels`, or DM to external user blocked
`MCP_SERVER_UNAUTHORIZED`	Agent's JWT does not include `slack` in `allowed_mcp_servers`
`MCP_TOOL_NOT_FOUND`	Tool name not in Slack MCP server's declared manifest
`MCP_ARGUMENT_SCHEMA_VIOLATION`	Required argument (`channel` or `user`) missing from call

Example: block message to unlisted channel

from scopebound import ScopeboundDenyError

try:
    adapter.enforce("post_to_channel", {"channel": "#all-company", "text": "Hello!"})
except ScopeboundDenyError as e:
    print(e.deny_code)   # PARAMETER_VIOLATION
    print(e.reason)      # "channel #all-company is not in allowed_channels"

Direct endpoint

curl -X POST https://your-partner.api.scopebound.ai/v1/mcp/enforce \
  -H "X-Scopebound-API-Key: sb-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "jwt": "your-session-jwt",
    "tool_name": "post_to_channel",
    "arguments": {"channel": "#engineering", "text": "Deploy complete"},
    "mcp_server": "slack",
    "mcp_tool_schema": {"required": ["channel", "text"]}
  }'