diff --git a/.env.example b/.env.example
index cac03bf..30c59ea 100644
--- a/.env.example
+++ b/.env.example
@@ -4,10 +4,18 @@ OPENROUTER_API_KEY=
 # Optional: API key required when the control plane enforces auth
 AGENTFIELD_API_KEY=
 
-# Optional model/provider overrides
-HARNESS_PROVIDER=opencode
+# AForge exec is the default. Set HARNESS_PROVIDER=opencode to roll back.
+HARNESS_PROVIDER=aforge
+# AForge headless command the SDK runs: `exec` (default) or `do`.
+# Read by agentfield>=0.1.130; any other value fails the harness call.
+AGENTFIELD_AFORGE_COMMAND=exec
 HARNESS_MODEL=openrouter/moonshotai/kimi-k2.5
 AI_MODEL=openrouter/moonshotai/kimi-k2.5
+# SEC_AF_AFORGE_BIN=/absolute/path/to/aforge
+
+# Build-time only: where `docker compose build` fetches the AForge CLI from.
+# AFORGE_BASE_URL=https://agentfield.ai/downloads/aforge
+# AFORGE_VERSION=v0.1.0
 
 # Optional: host path with repositories to scan/mirror into /workspaces
 # Example: SCAN_REPOS_PATH=../repos
diff --git a/Dockerfile b/Dockerfile
index 6b1c5a3..c08e470 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,3 +1,40 @@
+# AForge CLI is fetched as a released, checksum-verified binary rather than
+# copied out of a container image, so the build depends only on the public
+# download host. Both ARGs are overridable (e.g. to point at a staging mirror).
+ARG AFORGE_BASE_URL=https://agentfield.ai/downloads/aforge
+ARG AFORGE_VERSION=v0.1.0
+
+FROM debian:bookworm-slim AS aforge
+
+ARG AFORGE_BASE_URL
+ARG AFORGE_VERSION
+# Provided automatically by BuildKit; defaults to amd64 for legacy builders.
+ARG TARGETARCH
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    curl && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /out
+
+# Download the gzipped release binary, decompress it, and verify the
+# *decompressed* SHA-256 against the release checksums.txt before use.
+RUN set -eux; \
+    arch="${TARGETARCH:-amd64}"; \
+    curl -fsSL "${AFORGE_BASE_URL}/${AFORGE_VERSION}/aforge-linux-${arch}.gz" -o aforge.gz; \
+    gunzip -c aforge.gz > aforge; \
+    rm aforge.gz; \
+    curl -fsSL "${AFORGE_BASE_URL}/${AFORGE_VERSION}/checksums.txt" -o checksums.txt; \
+    tr -d '\r' < checksums.txt \
+        | grep " aforge-linux-${arch}$" \
+        | sed 's/  aforge-linux-.*/  aforge/' > aforge.sha256; \
+    test -s aforge.sha256; \
+    sha256sum -c aforge.sha256; \
+    rm checksums.txt aforge.sha256; \
+    chmod +x aforge
+
+
 FROM python:3.11-slim AS builder
 
 ENV PYTHONDONTWRITEBYTECODE=1 \
@@ -14,7 +51,7 @@ COPY pyproject.toml README.md ./
 COPY src/ src/
 
 RUN pip install --no-cache-dir --prefix=/install \
-    "agentfield>=0.1.0" \
+    "agentfield>=0.1.130" \
     "pydantic>=2.0" \
     "httpx>=0.27" \
     "python-dotenv>=1.0" && \
@@ -25,7 +62,8 @@ FROM python:3.11-slim AS runtime
 
 ENV PYTHONDONTWRITEBYTECODE=1 \
     PYTHONUNBUFFERED=1 \
-    HARNESS_PROVIDER=opencode \
+    HARNESS_PROVIDER=aforge \
+    AGENTFIELD_AFORGE_COMMAND=exec \
     HARNESS_MODEL=openrouter/minimax/minimax-m2.5 \
     AI_MODEL=openrouter/minimax/minimax-m2.5 \
     PORT=8080 \
@@ -53,6 +91,7 @@ RUN mkdir -p /home/secaf/.config/opencode && \
     chown -R secaf:secaf /home/secaf/.config
 
 COPY --from=builder /install /usr/local
+COPY --from=aforge /out/aforge /usr/local/bin/aforge
 COPY src/ /app/src/
 
 USER secaf
diff --git a/README.md b/README.md
index 4ee88ef..6450afb 100644
--- a/README.md
+++ b/README.md
@@ -143,7 +143,7 @@ The pipeline adapts at runtime based on what it discovers. An AI gate examines r
 
 **6. Guided autonomy for coding agents**
 
-SEC-AF runs on top of coding agents (Claude Code, OpenCode, Codex) via the AgentField harness. Rather than giving the agent a single massive prompt, each reasoner provides phase-aware guided autonomy: the agent receives a narrow task definition, a flat output schema (2-4 fields), and strategy-specific context. The agent has full autonomy within these boundaries — it can read files, trace code, and reason freely — but the harness constrains the _shape_ of its output. This prevents the common failure mode where autonomous agents go off-task or produce unstructured results.
+SEC-AF runs on top of coding agents (AForge, Claude Code, OpenCode, Codex) via the AgentField harness. Rather than giving the agent a single massive prompt, each reasoner provides phase-aware guided autonomy: the agent receives a narrow task definition, a flat output schema (2-4 fields), and strategy-specific context. The agent has full autonomy within these boundaries — it can read files, trace code, and reason freely — but the harness constrains the _shape_ of its output. This prevents the common failure mode where autonomous agents go off-task or produce unstructured results.
 
 **7. Composable reasoner DAG with full observability**
 
@@ -477,13 +477,46 @@ jobs:
 | `SEC_AF_MAX_TURNS` | No | `50` | Max harness turns per call |
 | `AGENTFIELD_API_KEY` | No | unset | API key for secured environments |
 | `SEC_AF_WORKSPACES_DIR` | No | `/workspaces` | Directory for cloned repos (falls back to `~/.sec-af/workspaces` if not writable) |
-| `HARNESS_PROVIDER` | No | `opencode` | Harness backend provider |
+| `HARNESS_PROVIDER` | No | `aforge` | Harness backend provider; set `opencode` for rollback |
+| `AGENTFIELD_AFORGE_COMMAND` | No | `exec` | AForge headless command the SDK runs: `exec` (default) or `do`. Read by agentfield>=0.1.130 |
+| `SEC_AF_AFORGE_BIN` | No | `aforge` | Path to an AForge binary for the `aforge` provider (also honours `AFORGE_BIN`) |
 | `SEC_AF_AI_MAX_RETRIES` | No | `3` | Retry count for model calls |
 
 </details>
 
+<details>
+<summary><strong>Build arguments</strong></summary>
+
+The image downloads the released AForge CLI at build time and verifies its
+SHA-256 against the release `checksums.txt` before installing it.
+
+| Build arg | Default | Description |
+|---|---|---|
+| `AFORGE_BASE_URL` | `https://agentfield.ai/downloads/aforge` | Root of the AForge download host |
+| `AFORGE_VERSION` | `v0.1.0` | Released AForge version to install |
+
+```bash
+docker build -t sec-af .
+docker build --build-arg AFORGE_VERSION=vX.Y.Z -t sec-af .
+```
+
+</details>
+
 ## Development Setup
 
+### Harness selection
+
+```bash
+export OPENROUTER_API_KEY=sk-or-v1-...
+export HARNESS_PROVIDER=aforge
+python -m sec_af.app
+```
+
+The container ships the AForge CLI at `/usr/local/bin/aforge` and drives it
+through `aforge exec` by default. To temporarily roll back without changing
+code, set `HARNESS_PROVIDER=opencode`. Running outside the container requires
+an `aforge` binary on `PATH` (or `SEC_AF_AFORGE_BIN` pointing at one).
+
 ```bash
 python -m venv .venv && source .venv/bin/activate
 pip install -e .[dev]
diff --git a/agentfield-package.yaml b/agentfield-package.yaml
index c677a4d..fae8a33 100644
--- a/agentfield-package.yaml
+++ b/agentfield-package.yaml
@@ -27,8 +27,13 @@ user_environment:
       type: secret
       scope: global
     - name: HARNESS_PROVIDER
-      description: Coding-agent harness provider
-      default: opencode
+      description: Coding-agent harness provider (aforge | claude-code | codex | gemini | opencode)
+      default: aforge
+    - name: AGENTFIELD_AFORGE_COMMAND
+      description: AForge headless command the SDK runs (`exec` or `do`); agentfield>=0.1.130 reads it, default `exec`
+      default: exec
+    - name: SEC_AF_AFORGE_BIN
+      description: Optional path to the AForge binary (defaults to aforge on PATH)
     - name: HARNESS_MODEL
       description: Model the harness uses
       default: openrouter/moonshotai/kimi-k2.5
diff --git a/docker-compose.yml b/docker-compose.yml
index b2c6ba2..6a48977 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -19,6 +19,9 @@ services:
     build:
       context: .
       dockerfile: Dockerfile
+      args:
+        AFORGE_BASE_URL: ${AFORGE_BASE_URL:-https://agentfield.ai/downloads/aforge}
+        AFORGE_VERSION: ${AFORGE_VERSION:-v0.1.0}
     ports:
       - "8003:8003"
     environment:
@@ -26,7 +29,8 @@ services:
       - AGENTFIELD_API_KEY=${AGENTFIELD_API_KEY:-}
       - PORT=8003
       - AGENT_CALLBACK_URL=http://sec-af:8003
-      - HARNESS_PROVIDER=opencode
+      - HARNESS_PROVIDER=${HARNESS_PROVIDER:-aforge}
+      - AGENTFIELD_AFORGE_COMMAND=${AGENTFIELD_AFORGE_COMMAND:-exec}
       - HARNESS_MODEL=${HARNESS_MODEL:-openrouter/moonshotai/kimi-k2.5}
       - AI_MODEL=${AI_MODEL:-openrouter/moonshotai/kimi-k2.5}
       - OPENROUTER_API_KEY=${OPENROUTER_API_KEY}
diff --git a/pyproject.toml b/pyproject.toml
index 747af56..ae35577 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,7 +11,7 @@ license = "Apache-2.0"
 requires-python = ">=3.11"
 authors = [{ name = "AgentField", email = "hello@agentfield.dev" }]
 dependencies = [
-    "agentfield>=0.1.0",
+    "agentfield>=0.1.130",
     "pydantic>=2.0",
     "httpx>=0.27",
 ]
diff --git a/src/sec_af/app.py b/src/sec_af/app.py
index a6c574a..3c7c895 100644
--- a/src/sec_af/app.py
+++ b/src/sec_af/app.py
@@ -45,6 +45,7 @@
         max_turns=_ai_config.max_turns,
         env=_ai_config.provider_env(),
         opencode_bin=_ai_config.opencode_bin,
+        aforge_bin=_ai_config.aforge_bin,
         permission_mode="auto",
     ),
     ai_config=AIConfig(
diff --git a/src/sec_af/config.py b/src/sec_af/config.py
index 382798c..3f56f53 100644
--- a/src/sec_af/config.py
+++ b/src/sec_af/config.py
@@ -47,7 +47,7 @@ class AuditConfig(BaseModel):
     exclude_paths: list[str] = Field(
         default_factory=lambda: ["tests/", "vendor/", "node_modules/", ".git/"],
     )
-    provider: str = "opencode"
+    provider: str = "aforge"
     budget: BudgetConfig = Field(default_factory=BudgetConfig)
 
     @classmethod
@@ -74,7 +74,7 @@ def from_input(cls, audit_input: AuditInput, repo_path: str) -> "AuditConfig":
 
 class AIIntegrationConfig(BaseModel):
     provider: str = Field(
-        default_factory=lambda: os.getenv("SEC_AF_PROVIDER", os.getenv("HARNESS_PROVIDER", "opencode"))
+        default_factory=lambda: os.getenv("SEC_AF_PROVIDER", os.getenv("HARNESS_PROVIDER", "aforge"))
     )
     harness_model: str = Field(
         default_factory=lambda: os.getenv(
@@ -95,6 +95,12 @@ class AIIntegrationConfig(BaseModel):
     )
     max_backoff_seconds: float = Field(default_factory=lambda: float(os.getenv("SEC_AF_AI_MAX_BACKOFF_SECONDS", "8.0")))
     opencode_bin: str = Field(default_factory=lambda: os.getenv("SEC_AF_OPENCODE_BIN", "opencode"))
+    aforge_bin: str = Field(
+        default_factory=lambda: os.getenv(
+            "SEC_AF_AFORGE_BIN",
+            os.getenv("AFORGE_BIN", "aforge"),
+        )
+    )
     opencode_server: str | None = Field(
         default_factory=lambda: os.getenv("SEC_AF_OPENCODE_SERVER", os.getenv("OPENCODE_SERVER")),
     )
@@ -113,6 +119,7 @@ def provider_env(self) -> dict[str, str]:
             "GH_TOKEN",
         )
         env: dict[str, str] = {key: value for key in env_keys if (value := os.getenv(key))}
+        env["AGENTFIELD_AFORGE_COMMAND"] = os.getenv("AGENTFIELD_AFORGE_COMMAND", "exec")
         xdg = os.getenv("XDG_DATA_HOME") or os.path.join(tempfile.gettempdir(), "opencode-shared-data")
         os.makedirs(xdg, exist_ok=True)
         env["XDG_DATA_HOME"] = xdg
diff --git a/tests/test_config.py b/tests/test_config.py
index adf903d..e241f78 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -4,6 +4,7 @@
 from typing import Any, cast
 
 import pytest
+from agentfield import HarnessConfig
 
 from sec_af.config import AIIntegrationConfig, AuditConfig, BudgetConfig, DepthProfile
 from sec_af.schemas.input import AuditInput
@@ -62,6 +63,7 @@ def test_ai_integration_config_uses_sec_af_env_precedence(monkeypatch: pytest.Mo
     monkeypatch.setenv("SEC_AF_AI_INITIAL_BACKOFF_SECONDS", "1.5")
     monkeypatch.setenv("SEC_AF_AI_MAX_BACKOFF_SECONDS", "12")
     monkeypatch.setenv("SEC_AF_OPENCODE_BIN", "/usr/local/bin/opencode")
+    monkeypatch.setenv("SEC_AF_AFORGE_BIN", "/usr/local/bin/aforge")
 
     config = AIIntegrationConfig.from_env()
 
@@ -73,6 +75,7 @@ def test_ai_integration_config_uses_sec_af_env_precedence(monkeypatch: pytest.Mo
     assert config.initial_backoff_seconds == 1.5
     assert config.max_backoff_seconds == 12
     assert config.opencode_bin == "/usr/local/bin/opencode"
+    assert config.aforge_bin == "/usr/local/bin/aforge"
 
 
 def test_ai_integration_config_falls_back_to_harness_and_defaults(monkeypatch: pytest.MonkeyPatch) -> None:
@@ -88,12 +91,14 @@ def test_ai_integration_config_falls_back_to_harness_and_defaults(monkeypatch: p
         "SEC_AF_AI_INITIAL_BACKOFF_SECONDS",
         "SEC_AF_AI_MAX_BACKOFF_SECONDS",
         "SEC_AF_OPENCODE_BIN",
+        "SEC_AF_AFORGE_BIN",
+        "AFORGE_BIN",
     ):
         monkeypatch.delenv(key, raising=False)
 
     config = AIIntegrationConfig.from_env()
 
-    assert config.provider == "opencode"
+    assert config.provider == "aforge"
     assert config.harness_model == "minimax/minimax-m2.5"
     assert config.ai_model == "minimax/minimax-m2.5"
     assert config.max_turns == 50
@@ -101,6 +106,8 @@ def test_ai_integration_config_falls_back_to_harness_and_defaults(monkeypatch: p
     assert config.initial_backoff_seconds == 2.0
     assert config.max_backoff_seconds == 8.0
     assert config.opencode_bin == "opencode"
+    assert config.aforge_bin == "aforge"
+    assert config.provider_env()["AGENTFIELD_AFORGE_COMMAND"] == "exec"
 
 
 def test_provider_env_only_includes_present_keys(monkeypatch: pytest.MonkeyPatch) -> None:
@@ -117,3 +124,29 @@ def test_provider_env_only_includes_present_keys(monkeypatch: pytest.MonkeyPatch
     assert env["GITHUB_TOKEN"] == "test-gh"
     assert "OPENROUTER_API_KEY" not in env
     assert "XDG_DATA_HOME" in env
+
+
+def test_audit_config_defaults_to_aforge_provider(sample_audit_input: AuditInput) -> None:
+    config = AuditConfig.from_input(sample_audit_input, repo_path="/tmp/sec-af-repo")
+
+    assert config.provider == "aforge"
+
+
+def test_pinned_agentfield_sdk_exposes_the_aforge_surface(monkeypatch: pytest.MonkeyPatch) -> None:
+    """The pinned AgentField SDK must accept the aforge harness settings app.py sends it."""
+    for key in ("SEC_AF_PROVIDER", "HARNESS_PROVIDER", "SEC_AF_AFORGE_BIN", "AFORGE_BIN"):
+        monkeypatch.delenv(key, raising=False)
+
+    config = AIIntegrationConfig.from_env()
+    harness_config = HarnessConfig(
+        provider=config.provider,
+        model=config.harness_model,
+        max_turns=config.max_turns,
+        env=config.provider_env(),
+        opencode_bin=config.opencode_bin,
+        aforge_bin=config.aforge_bin,
+        permission_mode="auto",
+    )
+
+    assert harness_config.provider == "aforge"
+    assert harness_config.aforge_bin == "aforge"