diff --git a/get-shit-done/workflows/execute-plan.md b/get-shit-done/workflows/execute-plan.md
index 39baccdd7..0da90b469 100644
--- a/get-shit-done/workflows/execute-plan.md
+++ b/get-shit-done/workflows/execute-plan.md
@@ -61,16 +61,17 @@ PLAN_START_EPOCH=$(date +%s)
 
 <step name="parse_segments">
 ```bash
-TASK_COUNT=$(grep -c "^<task" .planning/phases/XX-name/{phase}-{plan}-PLAN.md 2>/dev/null || echo "0")
+# Count tasks — match <task tag at any indentation level
+TASK_COUNT=$(grep -cE '^\s*<task[[:space:]>]' .planning/phases/XX-name/{phase}-{plan}-PLAN.md 2>/dev/null || echo "0")
 INLINE_THRESHOLD=$(node "$HOME/.claude/get-shit-done/bin/gsd-tools.cjs" config-get workflow.inline_plan_threshold --default 2 2>/dev/null || echo "2")
 grep -n "type=\"checkpoint" .planning/phases/XX-name/{phase}-{plan}-PLAN.md
 ```
 
 **Primary routing: task count threshold (#1979)**
 
-If `TASK_COUNT <= INLINE_THRESHOLD`: Use Pattern C (inline) regardless of checkpoint type. Small plans execute faster inline — avoids ~14K token subagent spawn overhead and preserves prompt cache. Configure threshold via `workflow.inline_plan_threshold` (default: 2).
+If `INLINE_THRESHOLD > 0` AND `TASK_COUNT <= INLINE_THRESHOLD`: Use Pattern C (inline) regardless of checkpoint type. Small plans execute faster inline — avoids ~14K token subagent spawn overhead and preserves prompt cache. Configure threshold via `workflow.inline_plan_threshold` (default: 2, set to `0` to always spawn subagents).
 
-If `TASK_COUNT > INLINE_THRESHOLD`: Apply checkpoint-based routing below.
+Otherwise: Apply checkpoint-based routing below.
 
 **Checkpoint-based routing (plans with > threshold tasks):**
 
diff --git a/tests/inline-plan-threshold.test.cjs b/tests/inline-plan-threshold.test.cjs
new file mode 100644
index 000000000..01f684c89
--- /dev/null
+++ b/tests/inline-plan-threshold.test.cjs
@@ -0,0 +1,131 @@
+/**
+ * Tests for workflow.inline_plan_threshold config key and routing logic (#1979).
+ *
+ * Verifies:
+ * 1. The config key is accepted by config-set (VALID_CONFIG_KEYS contains it)
+ * 2. The key is documented in planning-config.md
+ * 3. The execute-plan.md routing instruction uses the correct grep pattern
+ *    (matches <task at any indentation, since PLAN.md templates differ)
+ * 4. The workflow guards threshold=0 to disable inline routing
+ */
+
+'use strict';
+
+const { test, describe, beforeEach, afterEach } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const { runGsdTools, createTempProject, cleanup } = require('./helpers.cjs');
+
+const repoRoot = path.resolve(__dirname, '..');
+const executePlanPath = path.join(repoRoot, 'get-shit-done', 'workflows', 'execute-plan.md');
+const planningConfigPath = path.join(repoRoot, 'get-shit-done', 'references', 'planning-config.md');
+const configCjsPath = path.join(repoRoot, 'get-shit-done', 'bin', 'lib', 'config.cjs');
+
+describe('inline_plan_threshold config key (#1979)', () => {
+  let tmpDir;
+
+  beforeEach(() => {
+    tmpDir = createTempProject();
+  });
+
+  afterEach(() => {
+    cleanup(tmpDir);
+  });
+
+  test('config-set accepts workflow.inline_plan_threshold', () => {
+    const result = runGsdTools('config-set workflow.inline_plan_threshold 3', tmpDir);
+    assert.ok(result.success, `config-set should accept workflow.inline_plan_threshold: ${result.error}`);
+  });
+
+  test('config-set accepts threshold=0 to disable inline routing', () => {
+    const result = runGsdTools('config-set workflow.inline_plan_threshold 0', tmpDir);
+    assert.ok(result.success, `config-set should accept 0: ${result.error}`);
+  });
+
+  test('VALID_CONFIG_KEYS in config.cjs contains workflow.inline_plan_threshold', () => {
+    const content = fs.readFileSync(configCjsPath, 'utf-8');
+    assert.match(
+      content,
+      /['"]workflow\.inline_plan_threshold['"]/,
+      'workflow.inline_plan_threshold must be in VALID_CONFIG_KEYS'
+    );
+  });
+
+  test('planning-config.md documents workflow.inline_plan_threshold', () => {
+    const content = fs.readFileSync(planningConfigPath, 'utf-8');
+    assert.match(
+      content,
+      /workflow\.inline_plan_threshold/,
+      'planning-config.md must document workflow.inline_plan_threshold'
+    );
+  });
+});
+
+describe('execute-plan.md routing instruction (#1979)', () => {
+  test('grep pattern matches <task at any indentation level', () => {
+    const content = fs.readFileSync(executePlanPath, 'utf-8');
+
+    // The new pattern should use \s* for leading whitespace, not ^ anchor alone
+    // Must match both "<task type=" (unindented) and "  <task type=" (indented)
+    assert.match(
+      content,
+      /TASK_COUNT=\$\(grep -cE '\^\\s\*<task/,
+      'grep pattern must allow any leading whitespace before <task'
+    );
+  });
+
+  test('inline routing is guarded by INLINE_THRESHOLD > 0', () => {
+    const content = fs.readFileSync(executePlanPath, 'utf-8');
+    assert.match(
+      content,
+      /INLINE_THRESHOLD\s*>\s*0.*TASK_COUNT\s*<=\s*INLINE_THRESHOLD/s,
+      'inline routing must be guarded by INLINE_THRESHOLD > 0 so threshold=0 disables it'
+    );
+  });
+
+  test('grep pattern does NOT use ^<task alone (would miss indented tasks)', () => {
+    const content = fs.readFileSync(executePlanPath, 'utf-8');
+    // The old buggy pattern: grep -c "^<task" with no whitespace allowance
+    const buggyPattern = /grep -c "\^<task"/;
+    assert.doesNotMatch(
+      content,
+      buggyPattern,
+      'must not use the buggy "^<task" pattern which misses indented tasks'
+    );
+  });
+
+  test('grep pattern matches real-world indented task formats', () => {
+    // Simulate how the grep pattern would behave against sample PLAN.md content
+    // Extract the pattern from execute-plan.md
+    const content = fs.readFileSync(executePlanPath, 'utf-8');
+    const patternMatch = content.match(/TASK_COUNT=\$\(grep -cE '([^']+)'/);
+    assert.ok(patternMatch, 'must find TASK_COUNT grep pattern');
+
+    const regexSource = patternMatch[1].replace(/\\s/g, '\\s').replace(/\[\[:space:\]>\]/, '[\\s>]');
+    const re = new RegExp(regexSource, 'gm');
+
+    // Test cases: should match all of these as single tasks
+    const samples = [
+      '<task type="auto">',
+      '  <task type="auto">',
+      '    <task type="checkpoint:decision">',
+      '\t<task type="auto">',
+    ];
+    for (const sample of samples) {
+      const matches = sample.match(re);
+      assert.ok(matches && matches.length > 0, `Pattern must match: ${JSON.stringify(sample)}`);
+    }
+
+    // Non-task lines should not match
+    const nonMatches = [
+      '<tasks>',
+      '</task>',
+      '// <task comment',
+    ];
+    for (const sample of nonMatches) {
+      const matches = sample.match(re);
+      assert.ok(!matches || matches.length === 0, `Pattern must NOT match: ${JSON.stringify(sample)}`);
+    }
+  });
+});