Initial open-source release

packages/context/src/sl/tools/sl-read-source.tool.ts

@@ -0,0 +1,63 @@
+import { z } from 'zod';
+import type { ToolContext, ToolOutput } from '../../tools/index.js';
+import { BaseSemanticLayerTool, type BaseSemanticLayerToolDeps } from './base-semantic-layer.tool.js';
+import { slToolConnectionIdSchema } from './connection-id-schema.js';
+
+const slReadSourceInputSchema = z.object({
+  connectionId: slToolConnectionIdSchema.describe('Data source connection ID'),
+  sourceName: z.string().describe('Name of the source to read'),
+});
+
+type SlReadSourceInput = z.infer<typeof slReadSourceInputSchema>;
+
+interface SlReadSourceStructured {
+  sourceName: string;
+  yaml: string;
+}
+
+export class SlReadSourceTool extends BaseSemanticLayerTool<typeof slReadSourceInputSchema> {
+  readonly name = 'sl_read_source';
+
+  constructor(deps: BaseSemanticLayerToolDeps) {
+    super(deps);
+  }
+
+  get description(): string {
+    return `<purpose>
+Read the raw YAML definition of a semantic layer source, including its SQL implementation.
+Use this when you need to understand how a source is built — e.g., before editing it with sl_edit_source or sl_write_source.
+</purpose>
+
+<when_to_use>
+- Before editing a source: understand its full definition (SQL, columns, measures, joins)
+- When debugging a source: see the underlying SQL query
+- When creating a new source based on an existing one
+</when_to_use>
+
+<when_not_to_use>
+- To discover what sources/measures/dimensions are available for querying — use sl_discover instead
+- To query data — use semantic_query or create_widget with slQuery
+</when_not_to_use>`;
+  }
+
+  get inputSchema() {
+    return slReadSourceInputSchema;
+  }
+
+  async call(input: SlReadSourceInput, context: ToolContext): Promise<ToolOutput<SlReadSourceStructured>> {
+    const { connectionId, sourceName } = input;
+
+    const yaml = await this.readSourceYaml(connectionId, sourceName, context);
+    if (!yaml) {
+      return {
+        markdown: `Source **${sourceName}** not found for connection ${connectionId}.`,
+        structured: { sourceName, yaml: '' },
+      };
+    }
+
+    return {
+      markdown: `## Source: ${sourceName}\n\n\`\`\`yaml\n${yaml}\n\`\`\``,
+      structured: { sourceName, yaml },
+    };
+  }
+}