feat: shadow-mode SQL pre-validation telemetry

packages/opencode/src/altimate/telemetry/index.ts

@@ -637,6 +637,20 @@ export namespace Telemetry {
         total_cost: number
       }
   // altimate_change end
+    // altimate_change start — pre-execution SQL validation telemetry
+    | {
+        type: "sql_pre_validation"
+        timestamp: number
+        session_id: string
+        /** skipped = no cache or stale, passed = valid SQL, blocked = invalid SQL caught, error = validation itself failed */
+        outcome: "skipped" | "passed" | "blocked" | "error"
+        /** why: no_cache, stale_cache, empty_cache, valid, non_structural, structural_error, validation_exception */
+        reason: string
+        schema_columns: number
+        duration_ms: number
+        error_message?: string
+      }
+    // altimate_change end
 
   /** SHA256 hash a masked error message for anonymous grouping. */
   export function hashError(maskedMessage: string): string {

packages/opencode/src/altimate/tools/sql-execute.ts

@@ -9,6 +9,9 @@ import { Telemetry } from "../telemetry"
 // altimate_change start — progressive disclosure suggestions
 import { PostConnectSuggestions } from "./post-connect-suggestions"
 // altimate_change end
+// altimate_change start — pre-execution SQL validation via cached schema
+import { getCache } from "../native/schema/cache"
+// altimate_change end
 
 export const SqlExecuteTool = Tool.define("sql_execute", {
   description: "Execute SQL against a connected data warehouse. Returns results as a formatted table.",
@@ -34,6 +37,14 @@ export const SqlExecuteTool = Tool.define("sql_execute", {
     }
     // altimate_change end
 
+    // altimate_change start — shadow-mode pre-execution SQL validation
+    // Runs validation against cached schema and emits sql_pre_validation telemetry,
+    // but does NOT block execution. Used to measure catch rate before deciding
+    // whether to enable blocking in a future release. Fire-and-forget so it
+    // doesn't add latency to the sql_execute hot path.
+    preValidateSql(args.query, args.warehouse).catch(() => {})
+    // altimate_change end
+
     try {
       const result = await Dispatcher.call("sql.execute", {
         sql: args.query,
@@ -91,6 +102,135 @@ export const SqlExecuteTool = Tool.define("sql_execute", {
   },
 })
 
+// altimate_change start — pre-execution SQL validation via cached schema
+const CACHE_TTL_MS = 24 * 60 * 60 * 1000 // 24 hours
+
+interface PreValidationResult {
+  blocked: boolean
+  error?: string
+}
+
+async function preValidateSql(sql: string, warehouse?: string): Promise<PreValidationResult> {
+  const startTime = Date.now()
+  try {
+    const cache = await getCache()
+    const status = cache.cacheStatus()
+
+    // Find the target warehouse in cache
+    const warehouseName = warehouse || status.warehouses[0]?.name
+    if (!warehouseName) {
+      trackPreValidation("skipped", "no_cache", 0, Date.now() - startTime)
+      return { blocked: false }
+    }
+
+    const warehouseStatus = status.warehouses.find((w) => w.name === warehouseName)
+    if (!warehouseStatus?.last_indexed) {
+      trackPreValidation("skipped", "no_cache", 0, Date.now() - startTime)
+      return { blocked: false }
+    }
+
+    // Check cache freshness
+    const cacheAge = Date.now() - new Date(warehouseStatus.last_indexed).getTime()
+    if (cacheAge > CACHE_TTL_MS) {
+      trackPreValidation("skipped", "stale_cache", 0, Date.now() - startTime)
+      return { blocked: false }
+    }
+
+    // Build schema context from cached columns
+    const columns = cache.listColumns(warehouseName, 10_000)
+    if (columns.length === 0) {
+      trackPreValidation("skipped", "empty_cache", 0, Date.now() - startTime)
+      return { blocked: false }
+    }
+
+    const schemaContext: Record<string, any> = {}
+    for (const col of columns) {
+      const tableName = col.schema_name ? `${col.schema_name}.${col.table}` : col.table
+      if (!schemaContext[tableName]) {
+        schemaContext[tableName] = []
+      }
+      schemaContext[tableName].push({
+        name: col.name,
+        type: col.data_type || "VARCHAR",
+        nullable: col.nullable,
+      })
+    }
+
+    // Validate SQL against cached schema
+    const validationResult = await Dispatcher.call("altimate_core.validate", {
+      sql,
+      schema_path: "",
+      schema_context: schemaContext,
+    })
+
+    const data = (validationResult.data ?? {}) as Record<string, any>
+    const errors = Array.isArray(data.errors) ? data.errors : []
+    const isValid = data.valid !== false && errors.length === 0
+
+    if (isValid) {
+      trackPreValidation("passed", "valid", columns.length, Date.now() - startTime)
+      return { blocked: false }
+    }
+
+    // Only block on high-confidence structural errors
+    const structuralErrors = errors.filter((e: any) => {
+      const msg = (e.message ?? "").toLowerCase()
+      return msg.includes("column") || msg.includes("table") || msg.includes("not found") || msg.includes("does not exist")
+    })
+
+    if (structuralErrors.length === 0) {
+      // Non-structural errors (ambiguous cases) — let them through
+      trackPreValidation("passed", "non_structural", columns.length, Date.now() - startTime)
+      return { blocked: false }
+    }
+
+    // Build helpful error with available columns
+    const errorMsgs = structuralErrors.map((e: any) => e.message).join("\n")
+    const referencedTables = Object.keys(schemaContext).slice(0, 10)
+    const availableColumns = referencedTables
+      .map((t) => `${t}: ${schemaContext[t].map((c: any) => c.name).join(", ")}`)
+      .join("\n")
+
+    const errorOutput = [
+      `Pre-execution validation failed (validated against cached schema):`,
+      ``,
+      errorMsgs,
+      ``,
+      `Available tables and columns:`,
+      availableColumns,
+      ``,
+      `Fix the query and retry. If the schema cache is outdated, run schema_index to refresh it.`,
+    ].join("\n")
+
+    trackPreValidation("blocked", "structural_error", columns.length, Date.now() - startTime, errorMsgs)
+    return { blocked: true, error: errorOutput }
+  } catch {
+    // Validation failure should never block execution
+    trackPreValidation("error", "validation_exception", 0, Date.now() - startTime)
+    return { blocked: false }
+  }
+}
+
+function trackPreValidation(
+  outcome: "skipped" | "passed" | "blocked" | "error",
+  reason: string,
+  schema_columns: number,
+  duration_ms: number,
+  error_message?: string,
+) {
+  Telemetry.track({
+    type: "sql_pre_validation",
+    timestamp: Date.now(),
+    session_id: Telemetry.getContext().sessionId,
+    outcome,
+    reason,
+    schema_columns,
+    duration_ms,
+    ...(error_message && { error_message: error_message.slice(0, 500) }),
+  })
+}
+// altimate_change end
+
 function formatResult(result: SqlExecuteResult): string {
   if (result.row_count === 0) return "(0 rows)"