fix(#2544): config-get exits 1 on missing key (was 10, UNIX convention is 1)

Change ErrorClassification for 'Key not found' in configGet from Validation
(exit 10) to Execution (exit 1), matching git config --get. Callers using
`gsd-sdk query config-get k || fallback` need a non-zero exit to trigger the
fallback branch; 10 worked technically but was semantically wrong and noisy.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sdk/src/query/config-query.test.ts

@@ -58,6 +58,43 @@ describe('configGet', () => {
     await expect(configGet(['nonexistent.key'], tmpDir)).rejects.toThrow(GSDError);
   });
 
+  it('throws GSDError with Execution classification for missing key (exit code 1 not 10)', async () => {
+    // Regression for #2544: missing key must exit 1, not 10 (Validation).
+    // Callers like `gsd-sdk query config-get k || default` rely on non-zero exit.
+    // ErrorClassification.Execution maps to exit code 1 (matches git config --get).
+    const { configGet } = await import('./config-query.js');
+    const { ErrorClassification } = await import('../errors.js');
+    await writeFile(
+      join(tmpDir, '.planning', 'config.json'),
+      JSON.stringify({ model_profile: 'quality' }),
+    );
+    let thrown: unknown;
+    try {
+      await configGet(['nonexistent.key'], tmpDir);
+    } catch (err) {
+      thrown = err;
+    }
+    expect(thrown).toBeInstanceOf(GSDError);
+    expect((thrown as GSDError).classification).toBe(ErrorClassification.Execution);
+  });
+
+  it('throws GSDError with Execution classification when traversal hits non-object', async () => {
+    const { configGet } = await import('./config-query.js');
+    const { ErrorClassification } = await import('../errors.js');
+    await writeFile(
+      join(tmpDir, '.planning', 'config.json'),
+      JSON.stringify({ workflow: 'a-string-not-an-object' }),
+    );
+    let thrown: unknown;
+    try {
+      await configGet(['workflow.auto_advance'], tmpDir);
+    } catch (err) {
+      thrown = err;
+    }
+    expect(thrown).toBeInstanceOf(GSDError);
+    expect((thrown as GSDError).classification).toBe(ErrorClassification.Execution);
+  });
+
   it('reads raw config without merging defaults', async () => {
     const { configGet } = await import('./config-query.js');
     // Write config with only model_profile -- no workflow section

sdk/src/query/config-query.ts

@@ -90,12 +90,12 @@ export const configGet: QueryHandler = async (args, projectDir) => {
   let current: unknown = config;
   for (const key of keys) {
     if (current === undefined || current === null || typeof current !== 'object') {
-      throw new GSDError(`Key not found: ${keyPath}`, ErrorClassification.Validation);
+      throw new GSDError(`Key not found: ${keyPath}`, ErrorClassification.Execution);
     }
     current = (current as Record<string, unknown>)[key];
   }
   if (current === undefined) {
-    throw new GSDError(`Key not found: ${keyPath}`, ErrorClassification.Validation);
+    throw new GSDError(`Key not found: ${keyPath}`, ErrorClassification.Execution);
   }
 
   return { data: current };

tests/bug-2544-config-get-exit-code.test.cjs

@@ -0,0 +1,44 @@
+'use strict';
+
+/**
+ * Bug #2544: `gsd-sdk query config-get` exits 0 on missing key.
+ *
+ * Callers that use `gsd-sdk query config-get k || fallback` rely on a
+ * non-zero exit code when the key is absent. The fix changes the
+ * ErrorClassification for "Key not found" from Validation (exit 10)
+ * to Execution (exit 1), matching the UNIX convention of `git config --get`.
+ */
+
+const { test, describe } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const CONFIG_QUERY_SRC = path.join(
+  __dirname, '..', 'sdk', 'src', 'query', 'config-query.ts',
+);
+
+describe('gsd-sdk config-get exit code for missing key (#2544)', () => {
+  test('config-query.ts source exists', () => {
+    assert.ok(fs.existsSync(CONFIG_QUERY_SRC), 'sdk/src/query/config-query.ts must exist');
+  });
+
+  test('"Key not found" throws with Execution classification, not Validation', () => {
+    const src = fs.readFileSync(CONFIG_QUERY_SRC, 'utf-8');
+    // Find the "Key not found" throw lines and confirm they use Execution, not Validation
+    const keyNotFoundLines = src
+      .split('\n')
+      .filter(line => line.includes('Key not found'));
+    assert.ok(keyNotFoundLines.length > 0, 'Source must contain "Key not found" throw(s)');
+    for (const line of keyNotFoundLines) {
+      assert.ok(
+        line.includes('Execution'),
+        `"Key not found" throw must use ErrorClassification.Execution (exit 1), got: ${line.trim()}`
+      );
+      assert.ok(
+        !line.includes('Validation'),
+        `"Key not found" throw must NOT use ErrorClassification.Validation (exit 10), got: ${line.trim()}`
+      );
+    }
+  });
+});