Automation MCP Gatekeeping

Automation & MCP Gatekeeping

Purpose

Decide whether an external automation connector or MCP (Model Context Protocol) server should be activated at all — and if so, with the minimum scope, an explicit approval record, and a concrete, reversible smoke test before any real action is taken. External automation (Rube/Composio, Zapier-style connectors, real Slack/Gmail/Notion/Jira/HubSpot/Sheets/payment/CRM tools) can read private data, send messages, move money, and mutate production systems.

The default posture is closed: no external connector is activated without a task classification, a least-privilege scope definition, and an explicit approval step. A local task that could be done with code, files, a test suite, or a local browser check must never pull in an external connector "just in case" or to save time.

When to use

• A task asks to touch a real external service (Slack, Gmail, Calendar, Notion, Sheets, Linear, Jira, HubSpot, Airtable, Stripe, a CRM, or an admin panel).
• Someone proposes installing, configuring, or enabling an MCP server, Rube, Composio, or any other vendor automation skill.
• An agent or skill requests new credentials, OAuth scopes, API keys, or tokens for an external service.
• You are reviewing whether an existing connector's permissions are wider than the current task requires.
• A recurring automation workflow is being designed and the tool chain needs a safety and scope review before first run.

When not to use

• The task is entirely local: editing code, running tests, building, reading files, or using a local browser. These never need an external connector.
• Reading public documentation or running offline analysis tools.
• The task is to configure the secrets manager or credential store itself — that is infrastructure work, not connector gatekeeping.

Procedure

1. Classify the task. Assign it to exactly one category: local work (code, files, tests, build, local DB, local browser), external-service work (a one-off action against a live external system), or recurring automation (a workflow that will run repeatedly, possibly unattended). Only the last two can justify activating a connector. If classification is local work, stop — no connector needed, and activating one adds unnecessary scope and risk.

2. Check for an already-approved path first. Before proposing any new connector, verify whether the task can be done with: (a) a native first-party integration already configured in the project, (b) an MCP server or automation tool already installed and in scope, or (c) a project-approved workflow. Use the approved path if one exists. Do not add a new vendor layer when an existing one covers the need.

3. Define the minimum scope precisely. Name the exact service, the exact operation (read a calendar event, post to a specific Slack channel, create a Linear issue), and the narrowest possible credential scope that performs it (e.g., channels:read + chat:write for a single channel — not admin). For OAuth flows, identify the minimum scopes by name. For API keys, identify the minimum permission tier offered by the service.

4. Require explicit approval before enabling. Installing, authenticating, configuring, or turning on any MCP server or external connector is a gated action. Present the request as a structured proposal (service, operation, scope, smoke test, revocation path, risk tier). Do not self-approve. Do not proceed until a human approves the proposal in writing.

5. Define a concrete smoke test. Before using the connector for any real or production action, define and run a safe, reversible test: read one item (not all), post to a sandbox or test channel, create a draft (not a sent message), query metadata (not data). The smoke test must be explicitly safe — it must not modify real data, send real messages, or charge real money.

6. Never simulate success. If no active tool exists, or if approval was not granted, report the gap plainly: "No active connector for Gmail exists. Approval is required before activation. The action was not performed." Do not narrate a success that did not happen.

7. Record the activation. After a successful smoke test and before any real use, document: what was activated, its exact scope, who approved it, the date, and the steps to revoke it. Store this record where the team can review it (e.g., a project decision log, a ticket, or a config comment).

Concrete checks

• Task is correctly classified as local / external-service / recurring — and the classification is shown, not assumed.
• A native or already-approved path was checked before proposing a new connector.
• Requested scope is least-privilege: read-only where the task only needs to read, single resource/channel/repo rather than account-wide.
• Credentials come from an env var or secret manager — never hardcoded, never printed in any output.
• Write, send, or destructive operations have explicit human approval recorded before execution.
• A reversible smoke test is defined and run before any production action.
• Activation, scope, approver name, approval date, and revocation steps are documented.
• The MCP server or connector source is trusted and has been reviewed for supply-chain risk (see 50-dependency-supply-chain-review).
• The connector is task-gated, not left always-on after the task completes.
• No action was narrated as complete without a real tool call confirming it.

Decision flow

task → classify: local / external-service / recurring
         │
         ├─ local ──────────────────────────────────────> NO connector. Do it locally.
         │
         └─ external-service or recurring
                  │
                  ▼
         native or first-party connector available? ──yes──> use it (still apply least-scope)
                  │ no
                  ▼
         approved MCP/automation already in scope? ──yes──> use it (confirm scope still fits)
                  │ no
                  ▼
         propose: service + operation + min scope + smoke test + revocation path + risk tier
                  │
                  ▼
         explicit approval received? ──no──> STOP. Report gap. Do NOT simulate success.
                  │ yes
                  ▼
         enable with least scope → run smoke test → confirm working → record activation
                  │
                  ▼
         execute real action → revoke or scope-down connector when task is complete

Risk tiers (gate strength calibrated to blast radius)

Commands

# Inspect which MCP servers are currently configured (Claude/Cursor/etc.)
# Locations vary by platform:
cat ~/.config/claude/claude_desktop_config.json 2>/dev/null | python3 -m json.tool | grep -A5 '"mcpServers"' || true
cat .mcp.json 2>/dev/null | python3 -m json.tool || true
cat .cursor/mcp.json 2>/dev/null | python3 -m json.tool || true

# List what scopes an OAuth token was granted (GitHub example)
curl -sH "Authorization: Bearer $GITHUB_TOKEN" https://api.github.com/rate_limit \
  -I 2>/dev/null | grep -i "x-oauth-scopes"

# Slack: verify a token's granted scopes (read-only API call)
curl -sH "Authorization: Bearer $SLACK_TOKEN" \
  https://slack.com/api/auth.test | python3 -m json.tool | grep -E '"ok"|"user"|"team"'

# Linear: confirm read-only token vs write token (check scopes in token settings)
curl -sH "Authorization: Bearer $LINEAR_TOKEN" \
  https://api.linear.app/graphql \
  -d '{"query":"{ viewer { id name } }"}' | python3 -m json.tool

# Smoke test pattern: read one item before any write
# Gmail (read-only, list one message ID only):
# curl -sH "Authorization: Bearer $GMAIL_TOKEN" \
#   "https://gmail.googleapis.com/gmail/v1/users/me/messages?maxResults=1" | python3 -m json.tool

# Verify credential is from env, never hardcoded:
rg -n "(SLACK|GMAIL|NOTION|STRIPE|LINEAR|JIRA|HUBSPOT)\w*\s*=\s*['\"][A-Za-z0-9_-]{10,}" \
  -g '!*.lock' -g '!node_modules' . 2>/dev/null || echo "No hardcoded tokens found"

# Check connector is not always-on (should be task-gated)
rg -n "mcpServers\|composio\|rube" .env .env.local .claude/settings.json 2>/dev/null | head -10

# Record activation (append to a project decision log)
# Replace variables with actuals before running
cat >> docs/connector-activations.md <<'EOF'
## Activation record
- Date: $(date -u +%Y-%m-%dT%H:%M:%SZ)
- Service: <service name>
- Operation: <exact operation>
- Scope granted: <scope names>
- Approved by: <name>
- Smoke test: <what was tested and the result>
- Revocation: <steps to revoke>
- Auto-revoke date: <date if applicable>
EOF

# Revoke a GitHub fine-grained token (read its ID first)
# curl -sH "Authorization: Bearer $GITHUB_TOKEN" https://api.github.com/installation/token \
#   | python3 -m json.tool | grep '"id"'
# Then: DELETE /installation/token/:id  (requires admin scope)

Scope minimization reference

Common issues & anti-patterns

• Activating a broad connector for a one-off read: an account-wide Gmail connector enabled to read one email. The connector lingers with full inbox access after the task. Apply least scope, and revoke or scope-down when the task is complete.
• Account-wide OAuth when a single resource would do: requesting repo (all repositories) when contents:read on a single repo is sufficient. Many services now offer fine-grained token scopes — use them.
• Installing an MCP server from an unreviewed source: a third-party MCP server runs with the same permissions as the agent using it. An unreviewed MCP server is an unreviewed dependency — apply the same supply-chain review you would apply to an npm package. Check the source, the maintainer, and what network calls the server makes.
• Hardcoding tokens in a skill or agent configuration file: "token": "xoxb-..." in .mcp.json or a skill file commits the token to the repository. Tokens must come from environment variables or a secret manager.
• "It probably worked" without a real tool call: narrating a success for an action that no active tool actually performed. If the connector is not active, the action did not happen. Report the gap, do not simulate.
• Treating Rube/Composio as always-on: keeping a write-capable connector active between tasks means every subsequent agent run inherits the capability. Task-gate connectors: enable for the task, revoke or scope-down after.
• Leaving no documented revocation path: "I enabled Slack write access" with no note on how to revoke it. A connector without a revocation path is a permanent footprint.
• Skipping the smoke test: proceeding directly to a real write action without first confirming the connector works on a safe, reversible operation. A write operation to a production channel that fails halfway is worse than a failed smoke test on a test channel.

Required output

Report in this structure:

## MCP / Automation Gatekeeping Decision

### Task classification
- Category: local / external-service / recurring
- Justification: one sentence.

### Approved path check
- Native/first-party connector available: yes/no
- Already-approved MCP/automation in scope: yes/no
- Path used: <name> or "none — new connector proposed"

### Connector proposal (if new activation needed)
- Service: <name>
- Operation: <exact action>
- Minimum scope: <scope names>
- Risk tier: read-only non-PII / read private-PII / write-outbound / money-production-destructive

### Approval status
- Approval received: yes/no
- Approved by: <name> / pending

### Smoke test plan
- Test action: <safe reversible action>
- Test target: <sandbox/test channel/draft>
- Pass criterion: <expected response>
- Result: pass / fail / not yet run

### Data and safety risk
- Data accessed: <description>
- Reversible: yes/no
- Audit log: yes/no

### Revocation steps
1. <specific step to remove or scope-down the connector>
2. ...

### Gap (if activation declined or tool unavailable)
- No active connector for <service>. Approval required before activation.
  The requested action was NOT performed.

Safety

• Default-closed: no external automation is activated without explicit approval. The absence of a "no" is not a "yes."
• Never print, log, or commit credentials, tokens, OAuth codes, or secrets — reference env var names only.
• Never run a money, production, or destructive external action without written approval and, where available, a dry-run or staging execution first.
• Only activate MCP servers and automation connectors from trusted, reviewed sources. Treat an unreviewed MCP server as untrusted code.
• Always leave a documented, actionable way to revoke access. If you cannot describe the revocation steps, do not activate the connector.
• If a task is misclassified as external when it is actually local, correct the classification and do the work locally — do not activate a connector unnecessarily.