diff --git a/.github/workflows/ab-testing-advisor.lock.yml b/.github/workflows/ab-testing-advisor.lock.yml
index 07fdbacb97f..162e8a38fc2 100644
--- a/.github/workflows/ab-testing-advisor.lock.yml
+++ b/.github/workflows/ab-testing-advisor.lock.yml
@@ -837,6 +837,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1388,6 +1391,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/ace-editor.lock.yml b/.github/workflows/ace-editor.lock.yml
index c0db8127921..818d3ff830a 100644
--- a/.github/workflows/ace-editor.lock.yml
+++ b/.github/workflows/ace-editor.lock.yml
@@ -739,6 +739,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/agent-performance-analyzer.lock.yml b/.github/workflows/agent-performance-analyzer.lock.yml
index eb63f910086..6f6b337c678 100644
--- a/.github/workflows/agent-performance-analyzer.lock.yml
+++ b/.github/workflows/agent-performance-analyzer.lock.yml
@@ -977,6 +977,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1537,6 +1540,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/agent-persona-explorer.lock.yml b/.github/workflows/agent-persona-explorer.lock.yml
index dc10a2b641c..ac75ab2274d 100644
--- a/.github/workflows/agent-persona-explorer.lock.yml
+++ b/.github/workflows/agent-persona-explorer.lock.yml
@@ -928,6 +928,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1479,6 +1482,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/archie.lock.yml b/.github/workflows/archie.lock.yml
index ac3dc47b3f1..6fe541e80df 100644
--- a/.github/workflows/archie.lock.yml
+++ b/.github/workflows/archie.lock.yml
@@ -881,6 +881,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1432,6 +1435,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/architecture-guardian.lock.yml b/.github/workflows/architecture-guardian.lock.yml
index 2d9d46e7aa8..7f7a4bbd10e 100644
--- a/.github/workflows/architecture-guardian.lock.yml
+++ b/.github/workflows/architecture-guardian.lock.yml
@@ -824,6 +824,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1354,6 +1357,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/artifacts-summary.lock.yml b/.github/workflows/artifacts-summary.lock.yml
index 22a07045ed5..8f308e6ba45 100644
--- a/.github/workflows/artifacts-summary.lock.yml
+++ b/.github/workflows/artifacts-summary.lock.yml
@@ -766,6 +766,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1298,6 +1301,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/auto-triage-issues.lock.yml b/.github/workflows/auto-triage-issues.lock.yml
index b6a3ccd35b2..8686a443189 100644
--- a/.github/workflows/auto-triage-issues.lock.yml
+++ b/.github/workflows/auto-triage-issues.lock.yml
@@ -846,6 +846,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1378,6 +1381,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/bot-detection.lock.yml b/.github/workflows/bot-detection.lock.yml
index 688ed5703a9..85d212fabf5 100644
--- a/.github/workflows/bot-detection.lock.yml
+++ b/.github/workflows/bot-detection.lock.yml
@@ -860,6 +860,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/brave.lock.yml b/.github/workflows/brave.lock.yml
index 84f4f554683..a5f189133f8 100644
--- a/.github/workflows/brave.lock.yml
+++ b/.github/workflows/brave.lock.yml
@@ -851,6 +851,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1401,6 +1404,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/breaking-change-checker.lock.yml b/.github/workflows/breaking-change-checker.lock.yml
index 8cc88ce75cc..9bc8694d375 100644
--- a/.github/workflows/breaking-change-checker.lock.yml
+++ b/.github/workflows/breaking-change-checker.lock.yml
@@ -808,6 +808,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1343,6 +1346,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/chaos-pr-bundle-fuzzer.lock.yml b/.github/workflows/chaos-pr-bundle-fuzzer.lock.yml
index f25a6468f86..e6b017dc75b 100644
--- a/.github/workflows/chaos-pr-bundle-fuzzer.lock.yml
+++ b/.github/workflows/chaos-pr-bundle-fuzzer.lock.yml
@@ -817,6 +817,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1361,6 +1364,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/ci-coach.lock.yml b/.github/workflows/ci-coach.lock.yml
index 69c47c1a8bc..bc0794aeafc 100644
--- a/.github/workflows/ci-coach.lock.yml
+++ b/.github/workflows/ci-coach.lock.yml
@@ -897,6 +897,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1461,6 +1464,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/cli-consistency-checker.lock.yml b/.github/workflows/cli-consistency-checker.lock.yml
index 73425192d18..57cb27132be 100644
--- a/.github/workflows/cli-consistency-checker.lock.yml
+++ b/.github/workflows/cli-consistency-checker.lock.yml
@@ -785,6 +785,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1309,6 +1312,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/code-scanning-fixer.lock.yml b/.github/workflows/code-scanning-fixer.lock.yml
index 9029de997be..e17febbb999 100644
--- a/.github/workflows/code-scanning-fixer.lock.yml
+++ b/.github/workflows/code-scanning-fixer.lock.yml
@@ -847,6 +847,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1419,6 +1422,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/code-simplifier.lock.yml b/.github/workflows/code-simplifier.lock.yml
index ac67c1d5831..20fc5fda438 100644
--- a/.github/workflows/code-simplifier.lock.yml
+++ b/.github/workflows/code-simplifier.lock.yml
@@ -922,6 +922,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1456,6 +1459,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/constraint-solving-potd.lock.yml b/.github/workflows/constraint-solving-potd.lock.yml
index 3d67a34c032..cfe24261cf4 100644
--- a/.github/workflows/constraint-solving-potd.lock.yml
+++ b/.github/workflows/constraint-solving-potd.lock.yml
@@ -776,6 +776,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1320,6 +1323,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/contribution-check.lock.yml b/.github/workflows/contribution-check.lock.yml
index cb9999d4afd..b292cfa76aa 100644
--- a/.github/workflows/contribution-check.lock.yml
+++ b/.github/workflows/contribution-check.lock.yml
@@ -905,6 +905,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1435,6 +1438,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/copilot-cli-deep-research.lock.yml b/.github/workflows/copilot-cli-deep-research.lock.yml
index 6bba276d0bf..c274de64c23 100644
--- a/.github/workflows/copilot-cli-deep-research.lock.yml
+++ b/.github/workflows/copilot-cli-deep-research.lock.yml
@@ -820,6 +820,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1372,6 +1375,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/copilot-opt.lock.yml b/.github/workflows/copilot-opt.lock.yml
index 8e3dc45a3fa..59dacd6ea58 100644
--- a/.github/workflows/copilot-opt.lock.yml
+++ b/.github/workflows/copilot-opt.lock.yml
@@ -855,6 +855,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1405,6 +1408,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/copilot-pr-merged-report.lock.yml b/.github/workflows/copilot-pr-merged-report.lock.yml
index ef11e8bdba1..234e878256e 100644
--- a/.github/workflows/copilot-pr-merged-report.lock.yml
+++ b/.github/workflows/copilot-pr-merged-report.lock.yml
@@ -733,6 +733,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1279,6 +1282,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/copilot-pr-nlp-analysis.lock.yml b/.github/workflows/copilot-pr-nlp-analysis.lock.yml
index 2a4857b521d..cc86f5bb5ee 100644
--- a/.github/workflows/copilot-pr-nlp-analysis.lock.yml
+++ b/.github/workflows/copilot-pr-nlp-analysis.lock.yml
@@ -892,6 +892,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1472,6 +1475,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/copilot-pr-prompt-analysis.lock.yml b/.github/workflows/copilot-pr-prompt-analysis.lock.yml
index 1160f88905a..3dd11739f53 100644
--- a/.github/workflows/copilot-pr-prompt-analysis.lock.yml
+++ b/.github/workflows/copilot-pr-prompt-analysis.lock.yml
@@ -843,6 +843,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1410,6 +1413,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/craft.lock.yml b/.github/workflows/craft.lock.yml
index da937b91a23..7707817f5ba 100644
--- a/.github/workflows/craft.lock.yml
+++ b/.github/workflows/craft.lock.yml
@@ -849,6 +849,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1405,6 +1408,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-agent-of-the-day-blog-writer.lock.yml b/.github/workflows/daily-agent-of-the-day-blog-writer.lock.yml
index 4f73de583a3..4e90b175e9a 100644
--- a/.github/workflows/daily-agent-of-the-day-blog-writer.lock.yml
+++ b/.github/workflows/daily-agent-of-the-day-blog-writer.lock.yml
@@ -954,6 +954,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1526,6 +1529,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-ambient-context-optimizer.lock.yml b/.github/workflows/daily-ambient-context-optimizer.lock.yml
index 3ef1accc27c..cd5dca99776 100644
--- a/.github/workflows/daily-ambient-context-optimizer.lock.yml
+++ b/.github/workflows/daily-ambient-context-optimizer.lock.yml
@@ -869,6 +869,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1401,6 +1404,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-architecture-diagram.lock.yml b/.github/workflows/daily-architecture-diagram.lock.yml
index d61436b0f1f..a3d5bf2b7a5 100644
--- a/.github/workflows/daily-architecture-diagram.lock.yml
+++ b/.github/workflows/daily-architecture-diagram.lock.yml
@@ -922,6 +922,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1479,6 +1482,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-assign-issue-to-user.lock.yml b/.github/workflows/daily-assign-issue-to-user.lock.yml
index ffa991dcebe..daf33d510a6 100644
--- a/.github/workflows/daily-assign-issue-to-user.lock.yml
+++ b/.github/workflows/daily-assign-issue-to-user.lock.yml
@@ -778,6 +778,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1309,6 +1312,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-byok-ollama-test.lock.yml b/.github/workflows/daily-byok-ollama-test.lock.yml
index b246423ca96..cadd53b30c4 100644
--- a/.github/workflows/daily-byok-ollama-test.lock.yml
+++ b/.github/workflows/daily-byok-ollama-test.lock.yml
@@ -776,6 +776,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1286,6 +1289,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-cli-performance.lock.yml b/.github/workflows/daily-cli-performance.lock.yml
index 866ea9fd34d..9a50ff8a35f 100644
--- a/.github/workflows/daily-cli-performance.lock.yml
+++ b/.github/workflows/daily-cli-performance.lock.yml
@@ -1033,6 +1033,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1601,6 +1604,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-cli-tools-tester.lock.yml b/.github/workflows/daily-cli-tools-tester.lock.yml
index 481aab27c23..07abc6a5f16 100644
--- a/.github/workflows/daily-cli-tools-tester.lock.yml
+++ b/.github/workflows/daily-cli-tools-tester.lock.yml
@@ -904,6 +904,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1428,6 +1431,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-community-attribution.lock.yml b/.github/workflows/daily-community-attribution.lock.yml
index efda1c585c0..0cd8eff1d57 100644
--- a/.github/workflows/daily-community-attribution.lock.yml
+++ b/.github/workflows/daily-community-attribution.lock.yml
@@ -937,6 +937,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1493,6 +1496,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-compiler-quality.lock.yml b/.github/workflows/daily-compiler-quality.lock.yml
index 304ff25c12e..a486038ae48 100644
--- a/.github/workflows/daily-compiler-quality.lock.yml
+++ b/.github/workflows/daily-compiler-quality.lock.yml
@@ -937,6 +937,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1501,6 +1504,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-compiler-threat-spec-optimizer.lock.yml b/.github/workflows/daily-compiler-threat-spec-optimizer.lock.yml
index 8cb420dc3a1..31339c92043 100644
--- a/.github/workflows/daily-compiler-threat-spec-optimizer.lock.yml
+++ b/.github/workflows/daily-compiler-threat-spec-optimizer.lock.yml
@@ -851,6 +851,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1391,6 +1394,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-experiment-report.lock.yml b/.github/workflows/daily-experiment-report.lock.yml
index 9f7d2aeac8f..419c47059ba 100644
--- a/.github/workflows/daily-experiment-report.lock.yml
+++ b/.github/workflows/daily-experiment-report.lock.yml
@@ -891,6 +891,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1453,6 +1456,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-file-diet.lock.yml b/.github/workflows/daily-file-diet.lock.yml
index cf7a0532cec..248bd7f5c68 100644
--- a/.github/workflows/daily-file-diet.lock.yml
+++ b/.github/workflows/daily-file-diet.lock.yml
@@ -878,6 +878,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1409,6 +1412,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-firewall-report.lock.yml b/.github/workflows/daily-firewall-report.lock.yml
index bbacd503091..eae13fd4825 100644
--- a/.github/workflows/daily-firewall-report.lock.yml
+++ b/.github/workflows/daily-firewall-report.lock.yml
@@ -846,6 +846,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1389,6 +1392,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-geo-optimizer.lock.yml b/.github/workflows/daily-geo-optimizer.lock.yml
index 6a9865f8f40..6ddd63f6a55 100644
--- a/.github/workflows/daily-geo-optimizer.lock.yml
+++ b/.github/workflows/daily-geo-optimizer.lock.yml
@@ -803,6 +803,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1341,6 +1344,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-hippo-learn.lock.yml b/.github/workflows/daily-hippo-learn.lock.yml
index c6c83856963..47e05300558 100644
--- a/.github/workflows/daily-hippo-learn.lock.yml
+++ b/.github/workflows/daily-hippo-learn.lock.yml
@@ -913,6 +913,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1477,6 +1480,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-issues-report.lock.yml b/.github/workflows/daily-issues-report.lock.yml
index 44f83e75b01..280ec0981a7 100644
--- a/.github/workflows/daily-issues-report.lock.yml
+++ b/.github/workflows/daily-issues-report.lock.yml
@@ -1043,6 +1043,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1622,6 +1625,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-malicious-code-scan.lock.yml b/.github/workflows/daily-malicious-code-scan.lock.yml
index 1040e6e713b..7db6f7eaff8 100644
--- a/.github/workflows/daily-malicious-code-scan.lock.yml
+++ b/.github/workflows/daily-malicious-code-scan.lock.yml
@@ -819,6 +819,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
diff --git a/.github/workflows/daily-mcp-concurrency-analysis.lock.yml b/.github/workflows/daily-mcp-concurrency-analysis.lock.yml
index 5afea361c58..46283fdcddc 100644
--- a/.github/workflows/daily-mcp-concurrency-analysis.lock.yml
+++ b/.github/workflows/daily-mcp-concurrency-analysis.lock.yml
@@ -936,6 +936,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN
@@ -1493,6 +1496,9 @@ jobs:
         run: |
           set -o pipefail
           printf '%s' "$(date +%s%3N)" > /tmp/gh-aw/agent_cli_start_ms.txt
+          trap 'rm -f /home/runner/.copilot/settings.json' EXIT
+          mkdir -p /home/runner/.copilot
+          printf '%s' '{"builtInAgents":{"rubberDuck":false}}' > /home/runner/.copilot/settings.json
           touch /tmp/gh-aw/agent-step-summary.md
           GH_AW_NODE_BIN=$(command -v node 2>/dev/null || true)
           export GH_AW_NODE_BIN