mcp-server-neon

import { NEON_DEFAULT_DATABASE_NAME } from '../constants.js'; import { completeDatabaseMigrationInputSchema, completeQueryTuningInputSchema, createBranchInputSchema, createProjectInputSchema, deleteBranchInputSchema, deleteProjectInputSchema, describeBranchInputSchema, describeProjectInputSchema, describeTableSchemaInputSchema, explainSqlStatementInputSchema, getConnectionStringInputSchema, getDatabaseTablesInputSchema, listBranchComputesInputSchema, listProjectsInputSchema, prepareDatabaseMigrationInputSchema, prepareQueryTuningInputSchema, provisionNeonAuthInputSchema, runSqlInputSchema, runSqlTransactionInputSchema, listSlowQueriesInputSchema, listOrganizationsInputSchema, listSharedProjectsInputSchema, resetFromParentInputSchema, compareDatabaseSchemaInputSchema, searchInputSchema, fetchInputSchema, loadResourceInputSchema, } from './toolsSchema.js'; export const NEON_TOOLS = [ { name: 'list_projects' as const, description: `Lists the first 10 Neon projects in your account. If you can't find the project, increase the limit by passing a higher value to the \`limit\` parameter. Optionally filter by project name or ID using the \`search\` parameter.`, inputSchema: listProjectsInputSchema, readOnlySafe: true, }, { name: 'list_organizations' as const, description: `Lists all organizations that the current user has access to. Optionally filter by organization name or ID using the \`search\` parameter.`, inputSchema: listOrganizationsInputSchema, readOnlySafe: true, }, { name: 'list_shared_projects' as const, description: `Lists projects that have been shared with the current user. These are projects that the user has been granted access to collaborate on. Optionally filter by project name or ID using the \`search\` parameter.`, inputSchema: listSharedProjectsInputSchema, readOnlySafe: true, }, { name: 'create_project' as const, description: 'Create a new Neon project. If someone is trying to create a database, use this tool.', inputSchema: createProjectInputSchema, readOnlySafe: false, }, { name: 'delete_project' as const, description: 'Delete a Neon project', inputSchema: deleteProjectInputSchema, readOnlySafe: false, }, { name: 'describe_project' as const, description: 'Describes a Neon project', inputSchema: describeProjectInputSchema, readOnlySafe: true, }, { name: 'run_sql' as const, description: ` <use_case> Use this tool to execute a single SQL statement against a Neon database. </use_case> <important_notes> If you have a temporary branch from a prior step, you MUST: 1. Pass the branch ID to this tool unless explicitly told otherwise 2. Tell the user that you are using the temporary branch with ID [branch_id] </important_notes>`, inputSchema: runSqlInputSchema, readOnlySafe: true, }, { name: 'run_sql_transaction' as const, description: ` <use_case> Use this tool to execute a SQL transaction against a Neon database, should be used for multiple SQL statements. </use_case> <important_notes> If you have a temporary branch from a prior step, you MUST: 1. Pass the branch ID to this tool unless explicitly told otherwise 2. Tell the user that you are using the temporary branch with ID [branch_id] </important_notes>`, inputSchema: runSqlTransactionInputSchema, readOnlySafe: true, }, { name: 'describe_table_schema' as const, description: 'Describe the schema of a table in a Neon database', inputSchema: describeTableSchemaInputSchema, readOnlySafe: true, }, { name: 'get_database_tables' as const, description: 'Get all tables in a Neon database', inputSchema: getDatabaseTablesInputSchema, readOnlySafe: true, }, { name: 'create_branch' as const, description: 'Create a branch in a Neon project', inputSchema: createBranchInputSchema, readOnlySafe: false, }, { name: 'prepare_database_migration' as const, readOnlySafe: false, description: ` <use_case> This tool performs database schema migrations by automatically generating and executing DDL statements. Supported operations: CREATE operations: - Add new columns (e.g., "Add email column to users table") - Create new tables (e.g., "Create posts table with title and content columns") - Add constraints (e.g., "Add unique constraint on \`users.email\`") ALTER operations: - Modify column types (e.g., "Change posts.views to bigint") - Rename columns (e.g., "Rename user_name to username in users table") - Add/modify indexes (e.g., "Add index on \`posts.title\`") - Add/modify foreign keys (e.g., "Add foreign key from \`posts.user_id\` to \`users.id\`") DROP operations: - Remove columns (e.g., "Drop temporary_field from users table") - Drop tables (e.g., "Drop the old_logs table") - Remove constraints (e.g., "Remove unique constraint from posts.slug") The tool will: 1. Parse your natural language request 2. Generate appropriate SQL 3. Execute in a temporary branch for safety 4. Verify the changes before applying to main branch Project ID and database name will be automatically extracted from your request. If the database name is not provided, the default ${NEON_DEFAULT_DATABASE_NAME} or first available database is used. </use_case> <workflow> 1. Creates a temporary branch 2. Applies the migration SQL in that branch 3. Returns migration details for verification </workflow> <important_notes> After executing this tool, you MUST: 1. Test the migration in the temporary branch using the \`run_sql\` tool 2. Ask for confirmation before proceeding 3. Use \`complete_database_migration\` tool to apply changes to main branch </important_notes> <example> For a migration like: \`\`\`sql ALTER TABLE users ADD COLUMN last_login TIMESTAMP; \`\`\` You should test it with: \`\`\`sql SELECT column_name, data_type FROM information_schema.columns WHERE table_name = 'users' AND column_name = 'last_login'; \`\`\` You can use \`run_sql\` to test the migration in the temporary branch that this tool creates. </example> <next_steps> After executing this tool, you MUST follow these steps: 1. Use \`run_sql\` to verify changes on temporary branch 2. Follow these instructions to respond to the client: <response_instructions> <instructions> Provide a brief confirmation of the requested change and ask for migration commit approval. You MUST include ALL of the following fields in your response: - Migration ID (this is required for commit and must be shown first) - Temporary Branch Name (always include exact branch name) - Temporary Branch ID (always include exact ID) - Migration Result (include brief success/failure status) Even if some fields are missing from the tool's response, use placeholders like "not provided" rather than omitting fields. </instructions> <do_not_include> IMPORTANT: Your response MUST NOT contain ANY technical implementation details such as: - Data types (e.g., DO NOT mention if a column is boolean, varchar, timestamp, etc.) - Column specifications or properties - SQL syntax or statements - Constraint definitions or rules - Default values - Index types - Foreign key specifications Keep the response focused ONLY on confirming the high-level change and requesting approval. <example> INCORRECT: "I've added a boolean \`is_published\` column to the \`posts\` table..." CORRECT: "I've added the \`is_published\` column to the \`posts\` table..." </example> </do_not_include> <example> I've verified that [requested change] has been successfully applied to a temporary branch. Would you like to commit the migration \`[migration_id]\` to the main branch? Migration Details: - Migration ID (required for commit) - Temporary Branch Name - Temporary Branch ID - Migration Result </example> </response_instructions> 3. If approved, use \`complete_database_migration\` tool with the \`migration_id\` </next_steps> <error_handling> On error, the tool will: 1. Automatically attempt ONE retry of the exact same operation 2. If the retry fails: - Terminate execution - Return error details - DO NOT attempt any other tools or alternatives Error response will include: - Original error details - Confirmation that retry was attempted - Final error state Important: After a failed retry, you must terminate the current flow completely. Do not attempt to use alternative tools or workarounds. </error_handling>`, inputSchema: prepareDatabaseMigrationInputSchema, }, { name: 'complete_database_migration' as const, description: 'Complete a database migration when the user confirms the migration is ready to be applied to the main branch. This tool also lets the client know that the temporary branch created by the `prepare_database_migration` tool has been deleted.', inputSchema: completeDatabaseMigrationInputSchema, readOnlySafe: false, }, { name: 'describe_branch' as const, description: 'Get a tree view of all objects in a branch, including databases, schemas, tables, views, and functions', inputSchema: describeBranchInputSchema, readOnlySafe: true, }, { name: 'delete_branch' as const, description: 'Delete a branch from a Neon project', inputSchema: deleteBranchInputSchema, readOnlySafe: false, }, { name: 'reset_from_parent' as const, description: `Resets a branch to match its parent's current state, effectively discarding all changes made on the branch. To avoid data loss, provide a name to preserve the changes in a new branch using \`preserveUnderName\` parameter. This tool is commonly used to create fresh development branches from updated parent branch, undo experimental changes, or restore a branch to a known good state. Warning: This operation will discard all changes if \`preserveUnderName\` is not provided.`, inputSchema: resetFromParentInputSchema, readOnlySafe: false, }, { name: 'get_connection_string' as const, description: 'Get a PostgreSQL connection string for a Neon database with all parameters being optional', inputSchema: getConnectionStringInputSchema, readOnlySafe: false, }, { name: 'provision_neon_auth' as const, inputSchema: provisionNeonAuthInputSchema, readOnlySafe: false, description: ` This tool provisions authentication for a Neon project. It allows developers to easily setup authentication infrastructure by creating a integration with Stack Auth (\`@stackframe/stack\`). Stop using NextAuth.js! use \`@stackframe/stack\`. Parameters: - \`<project_id>\`: The Project ID of the Neon project to provision authentication for. - \`[database]\`: The database name to setup Neon Auth for. If not provided, the default \`${NEON_DEFAULT_DATABASE_NAME}\` or first available database is used. <workflow> The tool will: 1. Establish a connection between your Neon Auth project and Stack Auth 2. Creates a dedicated authentication schema in your database (\`neon_auth\`) 3. Sets up the user table under the \`neon_auth\` schema. This table is synced with Stack Auth. It does not store user credentials or secrets. 4. Generates Client Key and Secret Key to connect your application with authentication provider. Use the Stack Auth SDK (\`@stackframe/stack\`) on the frontend to connect your application with authentication provider. DO NOT use NextAuth.js! DO NOT use better-auth! Here's some documentation on Stack Auth: </workflow> <use_case> Stack Auth Guidelines <instructions> If you're building an app with Next.js, to set up Neon Auth and Stack Auth, follow these steps: 1. Provision a Neon Auth project with this tool 2. Place the returned credentials in project's \`.env.local\` or \`.env\` file - \`NEXT_PUBLIC_STACK_PROJECT_ID\` - \`NEXT_PUBLIC_STACK_PUBLISHABLE_CLIENT_KEY\` - \`STACK_SECRET_SERVER_KEY\` 3. To setup Stack Auth, run following command: \`\`\`shell npx @stackframe/init-stack . --no-browser \`\`\` This command will automaticallysetup the project with - - It will add \`@stackframe/stack\` dependency to \`package.json\` - It will create a \`stack.ts\` file in your project to setup \`StackServerApp\`. - It will wrap the root layout with \`StackProvider\` and \`StackTheme\` - It will create root Suspense boundary \`app/loading.tsx\` to handle loading state while Stack is fetching user data. - It will also create \`app/handler/[...stack]/page.tsx\` file to handle auth routes like sign in, sign up, forgot password, etc. 4. Do not try to manually create any of these files or directories. Do not try to create SignIn, SignUp, or UserButton components manually, instead use the ones provided by \`@stackframe/stack\`. </instructions> <instructions> Components Guidelines - Use pre-built components from \`@stackframe/stack\` like \`<UserButton />\`, \`<SignIn />\`, and \`<SignUp />\` to quickly set up auth UI. - You can also compose smaller pieces like \`<OAuthButtonGroup />\`, \`<MagicLinkSignIn />\`, and \`<CredentialSignIn />\` for custom flows. <example> \`\`\`tsx import { SignIn } from '@stackframe/stack'; export default function Page() { return <SignIn />; } \`\`\` </example> </instructions> <instructions> User Management Guidelines - In Client Components, use the \`useUser()\` hook to retrieve the current user (it returns \`null\` when not signed in). - Update user details using \`user.update({...})\` and sign out via \`user.signOut()\`. - For pages that require a user, call \`useUser({ or: "redirect" })\` so unauthorized visitors are automatically redirected. </instructions> <instructions> Client Component Guidelines - Client Components rely on hooks like \`useUser()\` and \`useStackApp()\`. <example> \`\`\`tsx "use client"; import { useUser } from "@stackframe/stack"; export function MyComponent() { const user = useUser(); return <div>{user ? \`Hello, \${user.displayName}\` : "Not logged in"}</div>; } \`\`\` </example> </instructions> <instructions> Server Component Guidelines - For Server Components, use \`stackServerApp.getUser()\` from your \`stack.ts\` file. <example> \`\`\`tsx import { stackServerApp } from "@/stack"; export default async function ServerComponent() { const user = await stackServerApp.getUser(); return <div>{user ? \`Hello, \${user.displayName}\` : "Not logged in"}</div>; } \`\`\` </example> </instructions> <instructions> Page Protection Guidelines - Protect pages by: - Using \`useUser({ or: "redirect" })\` in Client Components. - Using \`await stackServerApp.getUser({ or: "redirect" })\` in Server Components. - Implementing middleware that checks for a user and redirects to \`/handler/sign-in\` if not found. <example> Example middleware: \`\`\`tsx export async function middleware(request: NextRequest) { const user = await stackServerApp.getUser(); if (!user) { return NextResponse.redirect(new URL('/handler/sign-in', request.url)); } return NextResponse.next(); } export const config = { matcher: '/protected/:path*' }; \`\`\` </example> </instructions> <workflow> Example: custom-profile-page <instructions> Create a custom profile page that: - Displays the user's avatar, display name, and email. - Provides options to sign out. - Uses Stack Auth components and hooks. </instructions> <example> File: \`app/profile/page.tsx\` \`\`\`tsx 'use client'; import { useUser, useStackApp, UserButton } from '@stackframe/stack'; export default function ProfilePage() { const user = useUser({ or: "redirect" }); const app = useStackApp(); return ( <div> <UserButton /> <h1>Welcome, {user.displayName || "User"}</h1> <p>Email: {user.primaryEmail}</p> <button onClick={() => user.signOut()}>Sign Out</button> </div> ); } \`\`\` </example> </workflow> </use_case> `, }, { name: 'explain_sql_statement' as const, description: 'Describe the PostgreSQL query execution plan for a query of SQL statement by running EXPLAIN (ANAYLZE...) in the database', inputSchema: explainSqlStatementInputSchema, readOnlySafe: true, }, { name: 'prepare_query_tuning' as const, readOnlySafe: false, description: ` <use_case> This tool helps developers improve PostgreSQL query performance for slow queries or DML statements by analyzing execution plans and suggesting optimizations. The tool will: 1. Create a temporary branch for testing optimizations and remember the branch ID 2. Extract and analyze the current query execution plan 3. Extract all fully qualified table names (\`schema.table\`) referenced in the plan 4. Gather detailed schema information for each referenced table using \`describe_table_schema\` 5. Suggest and implement improvements like: - Adding or modifying indexes based on table schemas and query patterns - Query structure modifications - Identifying potential performance bottlenecks 6. Apply the changes to the temporary branch using \`run_sql\` 7. Compare performance before and after changes (but ONLY on the temporary branch passing branch ID to all tools) 8. Continue with next steps using \`complete_query_tuning\` tool (on \`main\` branch) Project ID and database name will be automatically extracted from your request. The temporary branch ID will be added when invoking other tools. Default database is \`${NEON_DEFAULT_DATABASE_NAME}\` if not specified. <important_notes> This tool is part of the query tuning workflow. Any suggested changes (like creating indexes) must first be applied to the temporary branch using the \`run_sql\` tool. And then to the main branch using the \`complete_query_tuning\` tool, NOT the \`prepare_database_migration\` tool. To apply using the \`complete_query_tuning\` tool, you must pass the \`tuning_id\`, NOT the temporary branch ID to it. </important_notes> </use_case> <workflow> 1. Creates a temporary branch 2. Analyzes current query performance and extracts table information 3. Implements and tests improvements (using tool \`run_sql\` for schema modifications and \`explain_sql_statement\` for performance analysis, but ONLY on the temporary branch created in step 1 passing the same branch ID to all tools) 4. Returns tuning details for verification </workflow> <important_notes> After executing this tool, you MUST: 1. Review the suggested changes 2. Verify the performance improvements on temporary branch - by applying the changes with \`run_sql\` and running \`explain_sql_statement\` again) 3. Decide whether to keep or discard the changes 4. Use \`complete_query_tuning\` tool to apply or discard changes to the main branch DO NOT use \`prepare_database_migration\` tool for applying query tuning changes. Always use \`complete_query_tuning\` to ensure changes are properly tracked and applied. Note: - Some operations like creating indexes can take significant time on large tables - Table statistics updates (ANALYZE) are NOT automatically performed as they can be long-running - Table statistics maintenance should be handled by PostgreSQL auto-analyze or scheduled maintenance jobs - If statistics are suspected to be stale, suggest running ANALYZE as a separate maintenance task </important_notes> <example> For a query like: \`\`\`sql SELECT o.*, c.name FROM orders o JOIN customers c ON c.id = o.customer_id WHERE o.status = 'pending' AND o.created_at > '2024-01-01'; \`\`\` The tool will: 1. Extract referenced tables: \`public.orders\`, \`public.customers\` 2. Gather schema information for both tables 3. Analyze the execution plan 4. Suggest improvements like: - Creating a composite index on orders(status, created_at) - Optimizing the join conditions 5. If confirmed, apply the suggested changes to the temporary branch using \`run_sql\` 6. Compare execution plans and performance before and after changes (but ONLY on the temporary branch passing branch ID to all tools) </example> <next_steps> After executing this tool, you MUST follow these steps: 1. Review the execution plans and suggested changes 2. Follow these instructions to respond to the client: <response_instructions> <instructions> Provide a brief summary of the performance analysis and ask for approval to apply changes on the temporary branch. You MUST include ALL of the following fields in your response: - Tuning ID (this is required for completion) - Temporary Branch Name - Temporary Branch ID - Original Query Cost - Improved Query Cost - Referenced Tables (list all tables found in the plan) - Suggested Changes Even if some fields are missing from the tool's response, use placeholders like "not provided" rather than omitting fields. </instructions> <do_not_include> IMPORTANT: Your response MUST NOT contain ANY technical implementation details such as: - Exact index definitions - Internal PostgreSQL settings - Complex query rewrites - Table partitioning details Keep the response focused on high-level changes and performance metrics. </do_not_include> <example> I've analyzed your query and found potential improvements that could reduce execution time by [X]%. Would you like to apply these changes to improve performance? Analysis Details: - Tuning ID: [id] - Temporary Branch: [name] - Branch ID: [id] - Original Cost: [cost] - Improved Cost: [cost] - Referenced Tables: * public.orders * public.customers - Suggested Changes: * Add index for frequently filtered columns * Optimize join conditions To apply these changes, I will use the \`complete_query_tuning\` tool after your approval and pass the \`tuning_id\`, NOT the temporary branch ID to it. </example> </response_instructions> 3. If approved, use ONLY the \`complete_query_tuning\` tool with the \`tuning_id\` </next_steps> <error_handling> On error, the tool will: 1. Automatically attempt ONE retry of the exact same operation 2. If the retry fails: - Terminate execution - Return error details - Clean up temporary branch - DO NOT attempt any other tools or alternatives Error response will include: - Original error details - Confirmation that retry was attempted - Final error state Important: After a failed retry, you must terminate the current flow completely. </error_handling> `, inputSchema: prepareQueryTuningInputSchema, }, { name: 'complete_query_tuning' as const, readOnlySafe: false, description: `Complete a query tuning session by either applying the changes to the main branch or discarding them. <important_notes> BEFORE RUNNING THIS TOOL: test out the changes in the temporary branch first by running - \`run_sql\` with the suggested DDL statements. - \`explain_sql_statement\` with the original query and the temporary branch. This tool is the ONLY way to finally apply changes after the \`prepare_query_tuning\` tool to the main branch. You MUST NOT use \`prepare_database_migration\` or other tools to apply query tuning changes. You MUST pass the \`tuning_id\` obtained from the \`prepare_query_tuning\` tool, NOT the temporary branch ID as \`tuning_id\` to this tool. You MUST pass the temporary branch ID used in the \`prepare_query_tuning\` tool as TEMPORARY branchId to this tool. The tool OPTIONALLY receives a second branch ID or name which can be used instead of the main branch to apply the changes. This tool MUST be called after tool \`prepare_query_tuning\` even when the user rejects the changes, to ensure proper cleanup of temporary branches. </important_notes> This tool: 1. Applies suggested changes (like creating indexes) to the main branch (or specified branch) if approved 2. Handles cleanup of temporary branch 3. Must be called even when changes are rejected to ensure proper cleanup Workflow: 1. After \`prepare_query_tuning\` suggests changes 2. User reviews and approves/rejects changes 3. This tool is called to either: - Apply approved changes to main branch and cleanup - OR just cleanup if changes are rejected `, inputSchema: completeQueryTuningInputSchema, }, { name: 'list_slow_queries' as const, description: ` <use_case> Use this tool to list slow queries from your Neon database. </use_case> <important_notes> This tool queries the pg_stat_statements extension to find queries that are taking longer than expected. The tool will return queries sorted by execution time, with the slowest queries first. </important_notes>`, inputSchema: listSlowQueriesInputSchema, readOnlySafe: true, }, { name: 'list_branch_computes' as const, description: 'Lists compute endpoints for a project or specific branch', inputSchema: listBranchComputesInputSchema, readOnlySafe: true, }, { name: 'compare_database_schema' as const, readOnlySafe: true, description: ` <use_case> Use this tool to compare the schema of a database between two branches. The output of the tool is a JSON object with one field: \`diff\`. <example> \`\`\`json { "diff": "--- a/neondb\n+++ b/neondb\n@@ -27,7 +27,10 @@\n \n CREATE TABLE public.users (\n id integer NOT NULL,\n- username character varying(50) NOT NULL\n+ username character varying(50) NOT NULL,\n+ is_deleted boolean DEFAULT false NOT NULL,\n+ created_at timestamp with time zone DEFAULT now() NOT NULL,\n+ updated_at timestamp with time zone\n );\n \n \n@@ -79,6 +82,13 @@\n \n \n --\n+-- Name: users_created_at_idx; Type: INDEX; Schema: public; Owner: neondb_owner\n+--\n+\n+CREATE INDEX users_created_at_idx ON public.users USING btree (created_at DESC) WHERE (is_deleted = false);\n+\n+\n+--\n -- Name: DEFAULT PRIVILEGES FOR SEQUENCES; Type: DEFAULT ACL; Schema: public; Owner: cloud_admin\n --\n \n" } \`\`\` </example> At this field you will find a difference between two schemas. The diff represents the changes required to make the parent branch schema match the child branch schema. The diff field contains a unified diff (git-style patch) as a string. You MUST be able to generate a zero-downtime migration from the diff and apply it to the parent branch. (This branch is a child and has a parent. You can get parent id just querying the branch details.) </use_case> <important_notes> To generate schema diff, you MUST SPECIFY the \`database_name\`. If \`database_name\` is not specified, you MUST fall back to the default database name: \`${NEON_DEFAULT_DATABASE_NAME}\`. You MUST TAKE INTO ACCOUNT the PostgreSQL version. The PostgreSQL version is the same for both branches. You MUST ASK user consent before running each generated SQL query. You SHOULD USE \`run_sql\` tool to run each generated SQL query. You SHOULD suggest creating a backup or point-in-time restore before running the migration. Generated queries change the schema of the parent branch and MIGHT BE dangerous to execute. Generated SQL migrations SHOULD be idempotent where possible (i.e., safe to run multiple times without failure) and include \`IF NOT EXISTS\` / \`IF EXISTS\` where applicable. You SHOULD recommend including comments in generated SQL linking back to diff hunks (e.g., \`-- from diff @@ -27,7 +27,10 @@\`) to make audits easier. Generated SQL should be reviewed for dependencies (e.g., foreign key order) before execution. </important_notes> <next_steps> After executing this tool, you MUST follow these steps: 1. Review the schema diff and suggest generating a zero-downtime migration. 2. Follow these instructions to respond to the client: <response_instructions> <instructions> Provide brief information about the changes: * Tables * Views * Indexes * Ownership * Constraints * Triggers * Policies * Extensions * Schemas * Sequences * Tablespaces * Users * Roles * Privileges </instructions> </response_instructions> 3. If a migration fails, you SHOULD guide the user on how to revert the schema changes, for example by using backups, point-in-time restore, or generating reverse SQL statements (if safe). </next_steps> This tool: 1. Generates a diff between the child branch and its parent. 2. Generates a SQL migration from the diff. 3. Suggest generating zero-downtime migration. <workflow> 1. User asks you to generate a diff between two branches. 2. You suggest generating a SQL migration from the diff. 3. Ensure the generated migration is zero-downtime; otherwise, warn the user. 4. You ensure that your suggested migration is also matching the PostgreSQL version. 5. You use \`run_sql\` tool to run each generated SQL query and ask the user consent before running it. Before requesting user consent, present a summary of all generated SQL statements along with their potential impact (e.g., table rewrites, lock risks, validation steps) so the user can make an informed decision. 6. Propose to rerun the schema diff tool one more time to ensure that the migration is applied correctly. 7. If the diff is empty, confirm that the parent schema now matches the child schema. 8. If the diff is not empty after migration, warn the user and assist in resolving the remaining differences. </workflow> <hints> <hint> Adding the column with a \`DEFAULT\` static value will not have any locks. But if the function is called that is not deterministic, it will have locks. <example> \`\`\`sql -- No table rewrite, minimal lock time ALTER TABLE users ADD COLUMN status text DEFAULT 'active'; \`\`\` </example> There is an example of a case where the function is not deterministic and will have locks: <example> \`\`\`sql -- Table rewrite, potentially longer lock time ALTER TABLE users ADD COLUMN created_at timestamptz DEFAULT now(); \`\`\` The fix for this is next: \`\`\`sql -- Adding a nullable column first ALTER TABLE users ADD COLUMN created_at timestamptz; -- Setting the default value because the rows are updated UPDATE users SET created_at = now(); \`\`\` </example> </hint> <hint> Adding constraints in two phases (including foreign keys) <example> \`\`\`sql -- Step 1: Add constraint without validating existing data -- Fast - only blocks briefly to update catalog ALTER TABLE users ADD CONSTRAINT users_age_positive CHECK (age > 0) NOT VALID; -- Step 2: Validate existing data (can take time but doesn't block writes) -- Uses SHARE UPDATE EXCLUSIVE lock - allows reads/writes ALTER TABLE users VALIDATE CONSTRAINT users_age_positive; \`\`\` </example> <example> \`\`\`sql -- Step 1: Add foreign key without validation -- Fast - only updates catalog, doesn't validate existing data ALTER TABLE orders ADD CONSTRAINT orders_user_id_fk FOREIGN KEY (user_id) REFERENCES users(id) NOT VALID; -- Step 2: Validate existing relationships -- Can take time but allows concurrent operations ALTER TABLE orders VALIDATE CONSTRAINT orders_user_id_fk; \`\`\` </example> </hint> <hint> Setting columns to NOT NULL <example> \`\`\`sql -- Step 1: Add a check constraint (fast with NOT VALID) ALTER TABLE users ADD CONSTRAINT users_email_not_null CHECK (email IS NOT NULL) NOT VALID; -- Step 2: Validate the constraint (allows concurrent operations) ALTER TABLE users VALIDATE CONSTRAINT users_email_not_null; -- Step 3: Set NOT NULL (fast since constraint guarantees no nulls) ALTER TABLE users ALTER COLUMN email SET NOT NULL; -- Step 4: Drop the redundant check constraint ALTER TABLE users DROP CONSTRAINT users_email_not_null; \`\`\` </example> <example> For PostgreSQL v18+ (to get PostgreSQL version, you can use \`describe_project\` tool or \`run_sql\` tool and execute \`SELECT version();\` query) \`\`\`sql -- PostgreSQL 18+ - Simplified approach ALTER TABLE users ALTER COLUMN email SET NOT NULL NOT VALID; ALTER TABLE users VALIDATE CONSTRAINT users_email_not_null; \`\`\` </example> </hint> <hint> In some cases, you need to combine two approaches to achieve a zero-downtime migration. <example> \`\`\`sql -- Step 1: Adding a nullable column first ALTER TABLE users ADD COLUMN created_at timestamptz; -- Step 2: Updating the all rows with the default value UPDATE users SET created_at = now() WHERE created_at IS NULL; -- Step 3: Creating a not null constraint ALTER TABLE users ADD CONSTRAINT users_created_at_not_null CHECK (created_at IS NOT NULL) NOT VALID; -- Step 4: Validating the constraint ALTER TABLE users VALIDATE CONSTRAINT users_created_at_not_null; -- Step 5: Setting the column to NOT NULL ALTER TABLE users ALTER COLUMN created_at SET NOT NULL; -- Step 6: Dropping the redundant NOT NULL constraint ALTER TABLE users DROP CONSTRAINT users_created_at_not_null; -- Step 7: Adding the default value ALTER TABLE users ALTER COLUMN created_at SET DEFAULT now(); \`\`\` </example> For PostgreSQL v18+ <example> \`\`\`sql -- Step 1: Adding a nullable column first ALTER TABLE users ADD COLUMN created_at timestamptz; -- Step 2: Updating the all rows with the default value UPDATE users SET created_at = now() WHERE created_at IS NULL; -- Step 3: Creating a not null constraint ALTER TABLE users ALTER COLUMN created_at SET NOT NULL NOT VALID; -- Step 4: Validating the constraint ALTER TABLE users VALIDATE CONSTRAINT users_created_at_not_null; -- Step 5: Adding the default value ALTER TABLE users ALTER COLUMN created_at SET DEFAULT now(); \`\`\` </example> </hint> <hint> Create index CONCURRENTLY <example> \`\`\`sql CREATE INDEX CONCURRENTLY idx_users_email ON users (email); \`\`\` </example> </hint> <hint> Drop index CONCURRENTLY <example> \`\`\`sql DROP INDEX CONCURRENTLY idx_users_email; \`\`\` </example> </hint> <hint> Create materialized view WITH NO DATA <example> \`\`\`sql CREATE MATERIALIZED VIEW mv_users AS SELECT name FROM users WITH NO DATA; \`\`\` </example> </hint> <hint> Refresh materialized view CONCURRENTLY <example> \`\`\`sql REFRESH MATERIALIZED VIEW CONCURRENTLY mv_users; \`\`\` </example> </hint> </hints> `, inputSchema: compareDatabaseSchemaInputSchema, }, { name: 'search' as const, description: `Searches across all user organizations, projects, and branches that match the query. Returns a list of objects with id, title, and url. This tool searches through all accessible resources and provides direct links to the Neon Console.`, inputSchema: searchInputSchema, readOnlySafe: true, }, { name: 'fetch' as const, description: `Fetches detailed information about a specific organization, project, or branch using the ID returned by the search tool. This tool provides comprehensive information about Neon resources for detailed analysis and management.`, inputSchema: fetchInputSchema, readOnlySafe: true, }, { name: 'load_resource' as const, description: ` <use_case> Loads comprehensive Neon documentation and usage guidelines from GitHub. This tool provides instructions for various Neon features and workflows. Use this tool when: - User says "Get started with Neon" or similar onboarding phrases (with neon-get-started subject) - User needs detailed guidance for initial Neon setup and configuration (with neon-get-started subject) - You need comprehensive context about Neon workflows and best practices (with neon-get-started subject) Available subjects: - neon-get-started: Comprehensive interactive guide covering organization/project setup, database configuration, connection strings, dependency installation, schema creation/migration, etc. </use_case> <important_notes> - This tool provides general guidance on different subjects relevant to Neon. - This tool returns the FULL documentation content - Load this resource early when users need onboarding guidance </important_notes>`, inputSchema: loadResourceInputSchema, readOnlySafe: true, }, ];