> ## Documentation Index > Fetch the complete documentation index at: https://docs.formal.ai/llms.txt > Use this file to discover all available pages before exploring further. # PlanetScale > Inspect PlanetScale databases, branches, and schemas, and run SQL queries. Data Publisher: PlanetScale Route PlanetScale MCP traffic through Formal to control and log what AI agents do in PlanetScale: * **Block** risky tools, such as `planetscale_execute_read_query`. * **Mask** sensitive data in tool results, such as emails and phone numbers in `planetscale_execute_read_query` responses. * **Keep credentials at the Connector**, so users and agents never see PlanetScale tokens. * **Log** every tool call with the user, the MCP client and its parameters. Cloud agents Laptop / VM Endpoint [https://mcp.pscale.dev/mcp/planetscale](https://mcp.pscale.dev/mcp/planetscale) Connector ![](https://docs.formal.ai/static/brands/mcp/planetscale.svg) ## 0. Prepare your Connector The Connector needs an MCP listener and a hostname with wildcard DNS and TLS. Set them up once by following [Deploy the Connector](https://docs.formal.ai/docs/guides/core-concepts/connectors/mcp-gateway.md#deploy-the-connector). Every MCP server reuses them. ## 1. Add PlanetScale MCP server to your Resources > [tab] UI > > 1. Open the [Admin Catalog](https://app.formal.ai/catalog) and click **Add MCP**. > 2. Select the **PlanetScale** template. > 3. Enter a DNS-label **Name**, such as `planetscale`. > 4. Choose the **Space** containing your Connector, such as `default`. > 5. Configure upstream authentication as described below, then save. > > If no Connector is in the selected Space, the **Configuration** tab shows **MCP clients can't connect directly yet**. > The reason reads: `No Connector is in this server's Space.` > > Adding PlanetScale to the Admin Catalog > [tab] Terraform > > Set `space_id` to the ID of the Space containing your Connector. > > ```hcl theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > resource "formal_resource" "planetscale" { > name = "planetscale" > technology = "mcp" > hostname = "mcp.pscale.dev" > space_id = "" > native_users_v3_enabled = true > port = 443 > tags = { > "mcp-endpoint" = "/mcp/planetscale" > } > } > > resource "formal_resource_oauth_settings" "planetscale" { > resource_id = formal_resource.planetscale.id > } > ``` > [tab] Pulumi > > Set `spaceId` to the ID of the Space containing your Connector. > > ```ts theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > import * as formal from "@formalco/pulumi"; > > const resource = new formal.Resource("mcp", { > name: "planetscale", > technology: "mcp", > hostname: "mcp.pscale.dev", > port: 443, > spaceId: "", > tags: { "mcp-endpoint": "/mcp/planetscale" }, > nativeUsersV3Enabled: true, > }); > > new formal.ResourceOauthSettings("mcpOAuth", { > resourceId: resource.id, > }); > ``` > [tab] API > > Create a Resource with the MCP endpoint and its Space ID. > > ```bash theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > export FORMAL_API_KEY="" > RESOURCE_RESPONSE=$(curl --fail --silent --show-error \ > --request POST \ > https://api.formal.ai/core.v1.ResourceService/CreateResource \ > --header "x-api-key: ${FORMAL_API_KEY}" \ > --header "Content-Type: application/json" \ > --data-binary @- < { > "name": "planetscale", > "hostname": "mcp.pscale.dev", > "port": 443, > "technology": "mcp", > "spaceId": "", > "tags": [ > { > "key": "mcp-endpoint", > "value": "/mcp/planetscale" > } > ] > } > JSON > ) > RESOURCE_ID=$(printf '%s' "${RESOURCE_RESPONSE}" | jq -r '.resource.id') > curl --fail --silent --show-error \ > --request POST \ > https://api.formal.ai/core.v1.ResourceService/CreateResourceOAuthSettings \ > --header "x-api-key: ${FORMAL_API_KEY}" \ > --header "Content-Type: application/json" \ > --data-binary @- < { > "resourceId": "${RESOURCE_ID}" > } > JSON > ``` ## 2. Setup Authentication > [tab] Linked Accounts (Recommended) > > Each user links their own PlanetScale account once in the Employee Catalog, and the Connector sends that user's token to PlanetScale. > > ![Linked Accounts selected under How does Formal authenticate to this resource?](https://mintcdn.com/formal/vzPMpIcsF4BYmdx8/assets/images/mcp-servers/auth-linked-accounts.png?fit=max\&auto=format\&n=vzPMpIcsF4BYmdx8\&q=85\&s=dc448db2a373faa6e1bf49fd5ffaf7c4) > > Under **OAuth app**, choose one of the two options. > > #### 1. Formal's App (default) > > Formal has a registered OAuth app with PlanetScale, so you register nothing. > Users see Formal on PlanetScale's consent screen. > > #### 2. Your OAuth App > > Users see your app's name on PlanetScale's consent screen. > > > [accordion] Set up your own PlanetScale OAuth app > > > > See [PlanetScale OAuth documentation](https://planetscale.com/docs/api/reference/oauth) and [register an app](https://app.planetscale.com). > > > > **1. Open OAuth applications** > > > > In your [PlanetScale organization](https://app.planetscale.com), open **Settings** → **OAuth applications**. > > > > **2. Register the application** > > > > Click **Create new application** and enter **Name**. > > > > **3. Set the callback** > > > > Set **Domain** to the callback’s domain, then paste Formal’s **Redirect URI** into **Redirect URI**. > > > > **4. Limit access scopes** > > > > Select only necessary access scopes, then click **Save access scopes**. > > > > **5. Copy credentials** > > > > Copy **Client ID** and the one-time **Client secret** shown after creating the application. > > > > **6. Enter the app in Formal** > > > > > [tab] UI > > > > > > Back in the Admin Catalog, enter the **Client ID** and **Client secret**, then save. > > > Users then link their accounts on the PlanetScale server's page in the [Employee Catalog](https://catalog.formal.ai). > > > > > > ![Your OAuth App selected in the Admin Catalog, with the Redirect URI, Client ID and Client secret fields](https://mintcdn.com/formal/R-3CwVgs8IU6liji/assets/images/mcp-servers/your-oauth-app.png?fit=max\&auto=format\&n=R-3CwVgs8IU6liji\&q=85\&s=00584678f4f2696805678de060eaea0a) > > > > > [tab] Terraform > > > > > > Use these OAuth settings instead of the ones from step 1. > > > > > > ```hcl theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > > > variable "planetscale_oauth_client_secret" { > > > type = string > > > sensitive = true > > > } > > > > > > resource "formal_resource_oauth_settings" "planetscale" { > > > resource_id = formal_resource.planetscale.id > > > upstream_oauth_mode = "pre_registered" > > > client_id = "" > > > client_secret_wo = var.planetscale_oauth_client_secret > > > client_secret_wo_version = 1 > > > } > > > ``` > > > > > [tab] Pulumi > > > > > > Use these OAuth settings instead of the ones from step 1. > > > Store the secret with `pulumi config set --secret planetscaleOauthClientSecret`. > > > > > > ```ts theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > > > import * as pulumi from "@pulumi/pulumi"; > > > > > > const config = new pulumi.Config(); > > > > > > new formal.ResourceOauthSettings("mcpOAuth", { > > > resourceId: resource.id, > > > upstreamOauthMode: "pre_registered", > > > clientId: "", > > > clientSecret: config.requireSecret("planetscaleOauthClientSecret"), > > > }); > > > ``` > > > > > [tab] API > > > > > > Use this call instead of the `CreateResourceOAuthSettings` call from step 1. > > > The OAuth app is fixed at creation. > > > > > > ```bash theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > > > curl --fail --silent --show-error \ > > > --request POST \ > > > https://api.formal.ai/core.v1.ResourceService/CreateResourceOAuthSettings \ > > > --header "x-api-key: ${FORMAL_API_KEY}" \ > > > --header "Content-Type: application/json" \ > > > --data-binary @- < > > { > > > "resourceId": "${RESOURCE_ID}", > > > "upstreamOauthMode": "pre_registered", > > > "clientId": "", > > > "clientSecret": "" > > > } > > > JSON > > > ``` > > > > > [!WARNING] > > > > > > Switching between Formal's App and your OAuth app unlinks every account. Users must link again. > [tab] Shared Credentials > > An administrator stores one PlanetScale token in Formal, and the Connector sends it on every user's requests without showing it to them. > > ![Shared Credentials selected under How does Formal authenticate to this resource?](https://mintcdn.com/formal/R-3CwVgs8IU6liji/assets/images/mcp-servers/auth-shared-credentials.png?fit=max\&auto=format\&n=R-3CwVgs8IU6liji\&q=85\&s=91032e202518088292ee1cf39451b9ef) > > PlanetScale's MCP endpoint accepts a [service token](https://planetscale.com/docs/connect/mcp-service-token) as a Bearer token. > Create one at [app.planetscale.com](https://app.planetscale.com). > Limit read\_database/read\_branch to target databases; add read\_databases for organization-wide listing and branch-specific connect/delete-credential permissions for SQL. > > 1. Open this server from the [Admin Catalog](https://app.formal.ai/catalog). > 2. Select **Configuration**, then **Authentication**. > 3. Choose **Shared Credentials**, then select **Add credential**. > 4. Enter the credential, make it the default, and select **Save authentication**. > > See [Native Users](https://docs.formal.ai/docs/guides/core-concepts/resources/native-users.md). > > For HTTP Bearer authentication, enter the raw token. The Connector adds the `Bearer ` prefix. > > In the Terraform tab, set `native_users_v3_enabled = true` on the Resource and `upstream_oauth_mode = "none"` on its OAuth settings. > > ```hcl theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > variable "mcp_shared_credential" { > type = string > sensitive = true > } > > resource "formal_native_user_v3" "mcp_shared_credential" { > resource_id = formal_resource.planetscale.id > label = "shared-credential" > > http_bearer { > header = "Authorization" > token { > literal_wo = var.mcp_shared_credential > literal_wo_version = 1 > } > } > } > > resource "formal_resource_native_user_selection" "mcp_shared_credential" { > resource_id = formal_resource.planetscale.id > cel = "\"${formal_native_user_v3.mcp_shared_credential.id}\"" > } > ``` > [tab] Pass Through > > Each user sends their own PlanetScale sign-in or token from their MCP client, and Formal forwards it unchanged without storing it. > > ![Pass Through selected under How does Formal authenticate to this resource?](https://mintcdn.com/formal/R-3CwVgs8IU6liji/assets/images/mcp-servers/auth-pass-through.png?fit=max\&auto=format\&n=R-3CwVgs8IU6liji\&q=85\&s=c14ae61de2dba8b567626cba03aae2cf) > > Nothing in the request identifies the Formal user. Formal attributes these requests only when they come through the [Formal Endpoint](https://docs.formal.ai/docs/guides/core-concepts/connectors/mcp-gateway.md#identity-headers). Pass-through servers have no Connector address, so cloud agents can't use them. > > For OAuth, each MCP client signs in to PlanetScale itself. ## 3. Route Endpoint traffic Auth is managed at the Connector level when you use Linked Accounts or Shared Credentials, so the Endpoint needs to forward the MCP traffic to it. Laptops and VMs with the Formal Endpoint keep using `https://mcp.pscale.dev/mcp/planetscale`, and a network rule sends that traffic to the Connector. > [tab] UI > > 1. Go to [Network Rules](https://app.formal.ai/network-rules) and create a rule named `planetscale-mcp`. > 2. Paste this expression, set the rule to **Active**, then save: > > ```javascript theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > { > "condition": { > "pre_tcp": process.is_agent, > // Every MCP server added to Formal: process.is_agent && resource.technology == "mcp" > "pre_tls": process.is_agent && hostname == "mcp.pscale.dev", > "post_tls": true > }, > "outputs": { > "forward_to_connector": true > } > } > ``` > [tab] Terraform > > ```hcl theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > resource "formal_network_rule" "planetscale_mcp" { > name = "planetscale-mcp" > description = "Forward PlanetScale MCP traffic from agents to the Connector" > status = "active" > > # Every MCP server added to Formal: set pre_tls to process.is_agent && resource.technology == "mcp" > cel_expression = <<-EOT > { > "condition": { > "pre_tcp": process.is_agent, > "pre_tls": process.is_agent && hostname == "mcp.pscale.dev", > "post_tls": true > }, > "outputs": { > "forward_to_connector": true > } > } > EOT > } > ``` > [tab] Pulumi > > ```ts theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > import * as formal from "@formalco/pulumi"; > > new formal.NetworkRule("planetscaleMcp", { > name: "planetscale-mcp", > description: "Forward PlanetScale MCP traffic from agents to the Connector", > status: "active", > // Every MCP server added to Formal: set pre_tls to process.is_agent && resource.technology == "mcp" > celExpression: ` > { > "condition": { > "pre_tcp": process.is_agent, > "pre_tls": process.is_agent && hostname == "mcp.pscale.dev", > "post_tls": true > }, > "outputs": { > "forward_to_connector": true > } > } > `, > }); > ``` > [tab] API > > ```bash theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > export FORMAL_API_KEY="" > # Every MCP server added to Formal: set pre_tls to process.is_agent && resource.technology == "mcp" > CEL_EXPRESSION=$(cat <<'CEL' > { > "condition": { > "pre_tcp": process.is_agent, > "pre_tls": process.is_agent && hostname == "mcp.pscale.dev", > "post_tls": true > }, > "outputs": { > "forward_to_connector": true > } > } > CEL > ) > jq -n --arg cel "${CEL_EXPRESSION}" '{ > name: "planetscale-mcp", > description: "Forward PlanetScale MCP traffic from agents to the Connector", > status: "active", > celExpression: $cel > }' | curl --fail --silent --show-error \ > --request POST \ > https://api.formal.ai/core.v1.DesktopService/CreateDesktopRoutingRule \ > --header "x-api-key: ${FORMAL_API_KEY}" \ > --header "Content-Type: application/json" \ > --data-binary @- > ``` The rule matches [known agents](https://docs.formal.ai/docs/guides/network-rules.md#known-agent-identities) only. See [Identity headers](https://docs.formal.ai/docs/guides/core-concepts/connectors/mcp-gateway.md#identity-headers). Cloud agents such as Claude, ChatGPT and Cursor Cloud Agents don't run the Endpoint. Point them at this server's Connector address, `https://planetscale./mcp`. Find it in the [Admin Catalog](https://app.formal.ai/catalog): open PlanetScale, then copy **Connector address** on the **Configuration** tab. ## 4. Create policies ### Tools The Admin Catalog lists these tools for PlanetScale: | Tool | Description | | - | - | | `planetscale_list_organizations` | List your PlanetScale organizations. | | `planetscale_list_databases` | List databases in an organization. | | `planetscale_get_database` | Get a database's details. | | `planetscale_list_branches` | List a database's branches. | | `planetscale_get_branch_schema` | Get a branch's schema. | | `planetscale_execute_read_query` | Run a read-only SQL query. | | `planetscale_execute_write_query` | Run a SQL query that changes data. | ### Policies examples > [tab] Block a tool > > This policy blocks the tools that change data, so agents can only read PlanetScale. > > ```rego theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > package formal.v2 > > import future.keywords.if > import future.keywords.in > > write_tools := { > "planetscale_execute_write_query", > } > > request := { > "action": "block", > "type": "block_with_custom_message", > "message": "Writing to PlanetScale is not allowed.", > } if { > input.resource.name == "planetscale" > input.mcp.method == "tools/call" > input.mcp.tool_name in write_tools > } > ``` > [tab] Mask a tool's output > > This policy replaces email addresses in results returned by `planetscale_execute_read_query`. > > ```rego theme={"languages":{"custom":["/languages/cel.json","/languages/rego.json"]}} > package formal.v2 > > import future.keywords.if > import future.keywords.in > > email_pattern := `[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}` > > response := { > "action": "rewrite", > "body": regex.replace(input.http.body, email_pattern, "[REDACTED-EMAIL]"), > "reason": "Mask emails in PlanetScale results", > } if { > input.resource.name == "planetscale" > input.mcp.tool_name in {"planetscale_execute_read_query"} > regex.match(email_pattern, input.http.body) > } > ``` See [MCP resources](https://docs.formal.ai/docs/guides/policies/evaluation.md#mcp-resources) for the `input.mcp` fields and [Rewrite Action](https://docs.formal.ai/docs/guides/policies/enforcement.md#rewrite-action) for body rewrites. ## 5. Check the logs Open [Logs](https://app.formal.ai/logs) and search for `resource.name:planetscale`. Each PlanetScale tool call is one `request` log with the user, the MCP client and the tool. Open a log to see its tool parameters and the policies it triggered. A blocked write shows the block policy and its message. A masked search shows the rewrite policy. PlanetScale tool calls in Logs, including a masked response and a blocked write See [Logs](https://docs.formal.ai/docs/guides/observability/logs.md) for search syntax and filters. ## Troubleshooting > [accordion] The agent says Formal has no current sign-in > > The agent relays: `Formal has no current planetscale sign-in for you. Link or re-link your planetscale account in Formal…` > > **Cause:** The user never linked PlanetScale, or the token expired and couldn't be refreshed. > > **Fix:** Open the server in the [Employee Catalog](https://catalog.formal.ai) and link PlanetScale again. > [accordion] The agent says PlanetScale rejected your credentials > > The agent relays: `planetscale rejected your credentials. Link or re-link your planetscale account in Formal…` > > **Cause:** PlanetScale no longer accepts the linked token, for example after the user revoked access in PlanetScale. > > **Fix:** Link PlanetScale again from the [Employee Catalog](https://catalog.formal.ai). > > With Shared Credentials, the message asks the user to contact an administrator. Replace the token in the server's **Shared Credentials**. > [accordion] Laptop traffic doesn't appear in Logs > > **Cause:** The Endpoint isn't running, or the network rule doesn't match the client. > > **Fix:** Check the Endpoint is connected. The rule above only matches [known agents](https://docs.formal.ai/docs/guides/network-rules.md#known-agent-identities). Other clients, such as a browser, reach PlanetScale directly unless the rule also matches them. See [Network rules](https://docs.formal.ai/docs/guides/network-rules.md). > [accordion] MCP clients can't connect directly yet > > **Cause:** The **Configuration** tab lists the reason, most often `No Connector is in this server's Space.` > > **Fix:** Edit the server and choose the Space containing its Connector. ## Next Steps > [card] [MCP Gateway](https://docs.formal.ai/docs/guides/core-concepts/connectors/mcp-gateway.md) > > Configure Connector routing and downstream access > [card] [All MCP servers](https://docs.formal.ai/docs/guides/core-concepts/connectors/mcp-servers/index.md) > > Browse every MCP server template This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.