diff --git a/commands/gsd/autonomous.md b/commands/gsd/autonomous.md
index bea90d6bb..fc2f0a3fe 100644
--- a/commands/gsd/autonomous.md
+++ b/commands/gsd/autonomous.md
@@ -1,7 +1,7 @@
 ---
 name: gsd:autonomous
 description: Run all remaining phases autonomously — discuss→plan→execute per phase
-argument-hint: "[--from N]"
+argument-hint: "[--from N] [--only N] [--interactive]"
 allowed-tools:
   - Read
   - Write
@@ -30,7 +30,10 @@ Uses ROADMAP.md phase discovery and Skill() flat invocations for each phase comm
 </execution_context>
 
 <context>
-Optional flag: `--from N` — start from phase N instead of the first incomplete phase.
+Optional flags:
+- `--from N` — start from phase N instead of the first incomplete phase.
+- `--only N` — execute only phase N (single-phase mode).
+- `--interactive` — run discuss inline with questions (not auto-answered), then dispatch plan→execute as background agents. Keeps the main context lean while preserving user input on decisions.
 
 Project context, phase list, and state are resolved inside the workflow using init commands (`gsd-tools.cjs init milestone-op`, `gsd-tools.cjs roadmap analyze`). No upfront context loading needed.
 </context>
diff --git a/get-shit-done/workflows/autonomous.md b/get-shit-done/workflows/autonomous.md
index 0a50a677a..d007a258c 100644
--- a/get-shit-done/workflows/autonomous.md
+++ b/get-shit-done/workflows/autonomous.md
@@ -16,7 +16,7 @@ Read all files referenced by the invoking prompt's execution_context before star
 
 ## 1. Initialize
 
-Parse `$ARGUMENTS` for `--from N` and `--only N` flags:
+Parse `$ARGUMENTS` for `--from N`, `--only N`, and `--interactive` flags:
 
 ```bash
 FROM_PHASE=""
@@ -29,10 +29,17 @@ if echo "$ARGUMENTS" | grep -qE '\-\-only\s+[0-9]'; then
   ONLY_PHASE=$(echo "$ARGUMENTS" | grep -oE '\-\-only\s+[0-9]+\.?[0-9]*' | awk '{print $2}')
   FROM_PHASE="$ONLY_PHASE"
 fi
+
+INTERACTIVE=""
+if echo "$ARGUMENTS" | grep -q '\-\-interactive'; then
+  INTERACTIVE="true"
+fi
 ```
 
 When `--only` is set, also set `FROM_PHASE` to the same value so existing filter logic applies.
 
+When `--interactive` is set, discuss runs inline with questions (not auto-answered), while plan and execute are dispatched as background agents. This keeps the main context lean — only discuss conversations accumulate — while preserving user input on all design decisions.
+
 Bootstrap via milestone-level init:
 
 ```bash
@@ -58,6 +65,7 @@ Display startup banner:
 
 If `ONLY_PHASE` is set, display: `Single phase mode: Phase ${ONLY_PHASE}`
 Else if `FROM_PHASE` is set, display: `Starting from phase ${FROM_PHASE}`
+If `INTERACTIVE` is set, display: `Mode: Interactive (discuss inline, plan+execute in background)`
 
 </step>
 
@@ -230,18 +238,26 @@ node "$HOME/.claude/get-shit-done/bin/gsd-tools.cjs" commit "docs(${PADDED_PHASE
 
 Proceed to 3b.
 
-**If SKIP_DISCUSS is `false` (or unset):** Execute the smart_discuss step for this phase.
+**If SKIP_DISCUSS is `false` (or unset):**
 
 **IMPORTANT — Discuss must be single-pass in autonomous mode.**
 The discuss step in `--auto` mode MUST NOT loop. If CONTEXT.md already exists after discuss completes, do NOT re-invoke discuss for the same phase. The `has_context` check below is authoritative — once true, discuss is done for this phase regardless of perceived "gaps" in the context file.
 
-After smart_discuss completes, verify context was written:
+**If `INTERACTIVE` is set:** Run the standard discuss-phase skill inline (asks interactive questions, waits for user answers). This preserves user input on all design decisions while keeping plan+execute out of the main context:
+
+```
+Skill(skill="gsd:discuss-phase", args="${PHASE_NUM}")
+```
+
+**If `INTERACTIVE` is NOT set:** Execute the smart_discuss step for this phase (batch table proposals, auto-optimized).
+
+After discuss completes (either mode), verify context was written:
 
 ```bash
 PHASE_STATE=$(node "$HOME/.claude/get-shit-done/bin/gsd-tools.cjs" init phase-op ${PHASE_NUM})
 ```
 
-Check `has_context`. If false → go to handle_blocker: "Smart discuss for phase ${PHASE_NUM} did not produce CONTEXT.md."
+Check `has_context`. If false → go to handle_blocker: "Discuss for phase ${PHASE_NUM} did not produce CONTEXT.md."
 
 **3a.5. UI Design Contract (Frontend Phases)**
 
@@ -284,6 +300,20 @@ UI_SPEC_FILE=$(ls "${PHASE_DIR}"/*-UI-SPEC.md 2>/dev/null | head -1)
 
 **3b. Plan**
 
+**If `INTERACTIVE` is set:** Dispatch plan as a background agent to keep the main context lean. While plan runs, the workflow can immediately start discussing the next phase (see step 4).
+
+```
+Agent(
+  description="Plan phase ${PHASE_NUM}: ${PHASE_NAME}",
+  run_in_background=true,
+  prompt="Run plan-phase for phase ${PHASE_NUM}: Skill(skill=\"gsd:plan-phase\", args=\"${PHASE_NUM}\")"
+)
+```
+
+Store the agent task_id. After discuss for the next phase completes (or if no next phase), wait for the plan agent to finish before proceeding to execute.
+
+**If `INTERACTIVE` is NOT set (default):** Run plan inline as before.
+
 ```
 Skill(skill="gsd:plan-phase", args="${PHASE_NUM}")
 ```
@@ -292,13 +322,29 @@ Verify plan produced output — re-run `init phase-op` and check `has_plans`. If
 
 **3c. Execute**
 
+**If `INTERACTIVE` is set:** Wait for the plan agent to complete (if not already), verify plans exist, then dispatch execute as a background agent:
+
+```
+Agent(
+  description="Execute phase ${PHASE_NUM}: ${PHASE_NAME}",
+  run_in_background=true,
+  prompt="Run execute-phase for phase ${PHASE_NUM}: Skill(skill=\"gsd:execute-phase\", args=\"${PHASE_NUM} --no-transition\")"
+)
+```
+
+Store the agent task_id. The workflow can now start discussing the next phase while this phase executes in the background. Before starting post-execution routing for this phase, wait for the execute agent to complete.
+
+**If `INTERACTIVE` is NOT set (default):** Run execute inline as before.
+
 ```
 Skill(skill="gsd:execute-phase", args="${PHASE_NUM} --no-transition")
 ```
 
 **3d. Post-Execution Routing**
 
-After execute-phase returns, read the verification result:
+**If `INTERACTIVE` is set:** Wait for the execute agent to complete before reading verification results.
+
+After execute-phase returns (or the execute agent completes), read the verification result:
 
 ```bash
 VERIFY_STATUS=$(grep "^status:" "${PHASE_DIR}"/*-VERIFICATION.md 2>/dev/null | head -1 | cut -d: -f2 | tr -d ' ')
@@ -733,6 +779,13 @@ Check for blockers in the Blockers/Concerns section. If blockers are found, go t
 
 If incomplete phases remain: proceed to next phase, loop back to execute_phase.
 
+**Interactive mode overlap:** When `INTERACTIVE` is set, the iterate step enables pipeline parallelism:
+1. After discuss completes for Phase N, dispatch plan+execute as background agents
+2. Immediately start discuss for Phase N+1 (the next incomplete phase) while Phase N builds
+3. Before starting plan for Phase N+1, wait for Phase N's execute agent to complete and handle its post-execution routing (verification, gap closure, etc.)
+
+This means the user is always answering discuss questions (lightweight, interactive) while the heavy work (planning, code generation) runs in the background. The main context only accumulates discuss conversations — plan and execute contexts are isolated in their agents.
+
 If all phases complete, proceed to lifecycle step.
 
 </step>
@@ -935,4 +988,10 @@ When any phase operation fails or a blocker is detected, present 3 options via A
 - [ ] `--only N` exits cleanly after single phase completes
 - [ ] `--only N` on already-complete phase exits with message
 - [ ] `--only N` handle_blocker resume message uses --only flag
+- [ ] `--interactive` runs discuss inline via gsd:discuss-phase (asks questions, waits for user)
+- [ ] `--interactive` dispatches plan and execute as background agents (context isolation)
+- [ ] `--interactive` enables pipeline parallelism: discuss Phase N+1 while Phase N builds
+- [ ] `--interactive` main context only accumulates discuss conversations (lean)
+- [ ] `--interactive` waits for background agents before post-execution routing
+- [ ] `--interactive` compatible with `--only` and `--from` flags
 </success_criteria>
diff --git a/tests/autonomous-interactive.test.cjs b/tests/autonomous-interactive.test.cjs
new file mode 100644
index 000000000..c5d6ba902
--- /dev/null
+++ b/tests/autonomous-interactive.test.cjs
@@ -0,0 +1,84 @@
+/**
+ * GSD Tools Tests - autonomous --interactive flag
+ *
+ * Validates that the autonomous workflow and command definition
+ * correctly document and support the --interactive flag.
+ *
+ * Closes: #1413
+ */
+
+const { test, describe } = require('node:test');
+const assert = require('node:assert');
+const fs = require('fs');
+const path = require('path');
+
+describe('autonomous --interactive flag (#1413)', () => {
+  const workflowPath = path.join(__dirname, '..', 'get-shit-done', 'workflows', 'autonomous.md');
+  const commandPath = path.join(__dirname, '..', 'commands', 'gsd', 'autonomous.md');
+
+  test('command definition includes --interactive in argument-hint', () => {
+    const content = fs.readFileSync(commandPath, 'utf8');
+    assert.ok(content.includes('--interactive'), 'command should document --interactive flag');
+    assert.ok(content.includes('argument-hint:') && content.includes('--interactive'),
+      'argument-hint should include --interactive');
+  });
+
+  test('command definition describes interactive mode behavior', () => {
+    const content = fs.readFileSync(commandPath, 'utf8');
+    assert.ok(content.includes('discuss') && content.includes('inline'),
+      'command should describe discuss running inline');
+    assert.ok(content.includes('background'),
+      'command should mention background agents for plan+execute');
+  });
+
+  test('workflow parses --interactive flag', () => {
+    const content = fs.readFileSync(workflowPath, 'utf8');
+    assert.ok(content.includes("--interactive") && content.includes('INTERACTIVE'),
+      'workflow should parse --interactive into INTERACTIVE variable');
+  });
+
+  test('workflow uses discuss-phase skill in interactive mode', () => {
+    const content = fs.readFileSync(workflowPath, 'utf8');
+    assert.ok(
+      content.includes('gsd:discuss-phase') && content.includes('INTERACTIVE'),
+      'workflow should invoke gsd:discuss-phase when INTERACTIVE is set'
+    );
+  });
+
+  test('workflow dispatches plan as background agent in interactive mode', () => {
+    const content = fs.readFileSync(workflowPath, 'utf8');
+    // Should have Agent() with run_in_background for plan
+    assert.ok(
+      content.includes('run_in_background') && content.includes('plan-phase'),
+      'workflow should dispatch plan-phase as background agent in interactive mode'
+    );
+  });
+
+  test('workflow dispatches execute as background agent in interactive mode', () => {
+    const content = fs.readFileSync(workflowPath, 'utf8');
+    assert.ok(
+      content.includes('run_in_background') && content.includes('execute-phase'),
+      'workflow should dispatch execute-phase as background agent in interactive mode'
+    );
+  });
+
+  test('workflow describes pipeline parallelism in interactive mode', () => {
+    const content = fs.readFileSync(workflowPath, 'utf8');
+    assert.ok(
+      content.includes('pipeline parallelism') || content.includes('Phase N+1'),
+      'workflow should describe overlapping discuss/execute between phases'
+    );
+  });
+
+  test('success criteria include --interactive requirements', () => {
+    const content = fs.readFileSync(workflowPath, 'utf8');
+    const criteriaMatch = content.match(/<success_criteria>([\s\S]*?)<\/success_criteria>/);
+    const criteria = criteriaMatch ? criteriaMatch[1] : '';
+    assert.ok(criteria.includes('--interactive'),
+      'success criteria should include --interactive requirements');
+    assert.ok(criteria.includes('discuss inline'),
+      'success criteria should mention discuss inline');
+    assert.ok(criteria.includes('background agents'),
+      'success criteria should mention background agents');
+  });
+});
diff --git a/tests/copilot-install.test.cjs b/tests/copilot-install.test.cjs
index 25ec66c1e..8f123b42b 100644
--- a/tests/copilot-install.test.cjs
+++ b/tests/copilot-install.test.cjs
@@ -651,7 +651,7 @@ describe('copyCommandsAsCopilotSkills', () => {
     assert.ok(skillContent.includes('description: Run all remaining phases autonomously'),
       'description preserved');
     // argument-hint present and double-quoted
-    assert.ok(skillContent.includes('argument-hint: "[--from N]"'), 'argument-hint present and quoted');
+    assert.ok(skillContent.includes('argument-hint: "[--from N] [--only N] [--interactive]"'), 'argument-hint present and quoted');
     // allowed-tools comma-separated
     assert.ok(skillContent.includes('allowed-tools: Read, Write, Bash, Glob, Grep, AskUserQuestion, Task'),
       'allowed-tools is comma-separated');