Blocks Slack message-write calls whose destination resolves to a direct conversation — a 1:1 DM, a message posted to a user ID (which Slack auto-opens as a…

slack.ingress.deny_direct_messages

slack access-control governance ingress

slack · ingress

Slack: Redact Sensitive Information from Messages

Redacts sensitive content from outgoing Slack message arguments before the call reaches Slack.

slack.ingress.redact_sensitive_info

slack pii secrets dlp redaction ingress

About these policies

Reusable DTwo policies for Slack MCP servers (the official Anthropic Slack MCP server and compatible implementations).

Available policies

Policy	Direction	Purpose
block-secrets	ingress	Deny send-message calls whose body looks like an API key, password, token, or private key.
deny-channel-creation	ingress	Deny Slack channel-creation tool calls; all other Slack tools pass through.
deny-read-search-summarize-sensitive-channels	ingress	Deny read, search, and summarize operations targeting sensitive channels (matched by channel ID).
deny-direct-messages	ingress	Deny message-write calls addressed to a direct conversation (1:1 DM, user ID, or group DM).
redact-sensitive-info	ingress	Redact secrets and PII from outgoing message content to `[REDACTED]` (transform-only); all other Slack tools pass through.

Tool naming on the DTwo gateway

DTwo prefixes tool names with the MCP server name configured on the gateway. A Slack MCP server registered as slack-mcp will surface tools like slack-mcp-slack-post-message, while one registered as slack will surface slack-slack-post-message. The policies in this directory match on the suffix (slack-post-message, slack-send-message, etc.) so they stay portable across naming conventions — but you should always confirm the exact tool name your gateway sends using the dump-input debug technique before deploying.

Identity claims

These policies do not require any specific IdP claims. If you want to add identity-based exemptions (e.g., an InfoSec break-glass user), gate the relevant allow rule with object.get(input.subject.claims, "<claim>", "<default>").

Contributing

To add a Slack policy:

Create apps/slack/<policy-slug>/ with policy.md and a tests.yaml test file.
Add a row to the table above.
Declare apps: ["slack"] in the policy frontmatter, plus any industry / bundle slugs that apply.
If the policy fits an industry or bundle (e.g. bundles/slack or bundles/im-messaging), link to it from the matching landing page.
Run pnpm manifest from the repo root.

See CONTRIBUTING.md for the full process.