import { z } from 'zod';
import type { ToolContext, ToolPrivilegeLevel } from './types.js';
import { executeSqlWithFallback, isSqlErrorResponse } from './utils.js';
// Output schema for trigger definition
const GetTriggerDefinitionOutputSchema = z.object({
schema_name: z.string(),
table_name: z.string(),
trigger_name: z.string(),
trigger_timing: z.string(),
trigger_level: z.string(),
events: z.array(z.string()),
function_schema: z.string(),
function_name: z.string(),
enabled: z.string(),
definition: z.string(),
function_definition: z.string().nullable(),
});
// Input schema
const GetTriggerDefinitionInputSchema = z.object({
schema: z.string().default('public').describe('Schema name (defaults to public).'),
table: z.string().describe('Table name the trigger is on.'),
trigger_name: z.string().describe('Name of the trigger.'),
include_function: z.boolean().optional().default(true).describe('Include the trigger function source code.'),
});
type GetTriggerDefinitionInput = z.infer<typeof GetTriggerDefinitionInputSchema>;
// Static JSON Schema for MCP capabilities
const mcpInputSchema = {
type: 'object',
properties: {
schema: {
type: 'string',
default: 'public',
description: 'Schema name (defaults to public).',
},
table: {
type: 'string',
description: 'Table name the trigger is on.',
},
trigger_name: {
type: 'string',
description: 'Name of the trigger.',
},
include_function: {
type: 'boolean',
default: true,
description: 'Include the trigger function source code.',
},
},
required: ['table', 'trigger_name'],
};
// SQL identifier validation pattern
const identifierPattern = /^[a-zA-Z_][a-zA-Z0-9_$]*$/;
export const getTriggerDefinitionTool = {
name: 'get_trigger_definition',
description: 'Gets the full definition of a trigger, optionally including its function source code.',
privilegeLevel: 'regular' as ToolPrivilegeLevel,
inputSchema: GetTriggerDefinitionInputSchema,
mcpInputSchema: mcpInputSchema,
outputSchema: GetTriggerDefinitionOutputSchema,
execute: async (input: GetTriggerDefinitionInput, context: ToolContext) => {
const client = context.selfhostedClient;
const { schema, table, trigger_name, include_function } = input;
// Validate identifiers
if (!identifierPattern.test(schema)) {
throw new Error(`Invalid schema name: ${schema}`);
}
if (!identifierPattern.test(table)) {
throw new Error(`Invalid table name: ${table}`);
}
if (!identifierPattern.test(trigger_name)) {
throw new Error(`Invalid trigger name: ${trigger_name}`);
}
const sql = `
SELECT
n.nspname AS schema_name,
c.relname AS table_name,
t.tgname AS trigger_name,
CASE
WHEN t.tgtype::int & 2 > 0 THEN 'BEFORE'
WHEN t.tgtype::int & 64 > 0 THEN 'INSTEAD OF'
ELSE 'AFTER'
END AS trigger_timing,
CASE WHEN t.tgtype::int & 1 > 0 THEN 'ROW' ELSE 'STATEMENT' END AS trigger_level,
ARRAY_REMOVE(ARRAY[
CASE WHEN t.tgtype::int & 4 > 0 THEN 'INSERT' END,
CASE WHEN t.tgtype::int & 8 > 0 THEN 'DELETE' END,
CASE WHEN t.tgtype::int & 16 > 0 THEN 'UPDATE' END,
CASE WHEN t.tgtype::int & 32 > 0 THEN 'TRUNCATE' END
], NULL) AS events,
pn.nspname AS function_schema,
p.proname AS function_name,
CASE t.tgenabled
WHEN 'O' THEN 'ENABLED'
WHEN 'D' THEN 'DISABLED'
WHEN 'R' THEN 'REPLICA'
WHEN 'A' THEN 'ALWAYS'
ELSE t.tgenabled::text
END AS enabled,
pg_catalog.pg_get_triggerdef(t.oid, true) AS definition,
${include_function ? 'pg_catalog.pg_get_functiondef(p.oid)' : 'NULL'} AS function_definition
FROM pg_catalog.pg_trigger t
JOIN pg_catalog.pg_class c ON c.oid = t.tgrelid
JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
JOIN pg_catalog.pg_proc p ON p.oid = t.tgfoid
JOIN pg_catalog.pg_namespace pn ON pn.oid = p.pronamespace
WHERE n.nspname = '${schema}'
AND c.relname = '${table}'
AND t.tgname = '${trigger_name}'
LIMIT 1
`;
const result = await executeSqlWithFallback(client, sql, true);
if (isSqlErrorResponse(result)) {
throw new Error(result.error.message || 'Failed to get trigger definition');
}
const rows = result as unknown[];
if (rows.length === 0) {
throw new Error(`Trigger "${trigger_name}" not found on ${schema}.${table}.`);
}
return GetTriggerDefinitionOutputSchema.parse(rows[0]);
},
};
