diff --git a/.agents/scripts/model-availability-helper.sh b/.agents/scripts/model-availability-helper.sh
index 1ae3963c0..a5e6c4d82 100755
--- a/.agents/scripts/model-availability-helper.sh
+++ b/.agents/scripts/model-availability-helper.sh
@@ -55,8 +55,11 @@ readonly DEFAULT_HEALTH_TTL=300    # 5 minutes for health checks
 readonly DEFAULT_RATELIMIT_TTL=60  # 1 minute for rate limit data
 readonly PROBE_TIMEOUT=10          # HTTP request timeout in seconds
 
-# Known providers list
-readonly KNOWN_PROVIDERS="anthropic openai google openrouter groq deepseek"
+# Known providers list (opencode is a meta-provider routing through its gateway)
+readonly KNOWN_PROVIDERS="anthropic openai google openrouter groq deepseek opencode"
+
+# OpenCode models cache (from models.dev, refreshed by opencode CLI)
+readonly OPENCODE_MODELS_CACHE="${HOME}/.cache/opencode/models.json"
 
 # Provider API endpoints for lightweight probes
 # These endpoints are chosen for minimal cost: /models endpoints are free
@@ -71,6 +74,7 @@ get_provider_endpoint() {
         openrouter) echo "https://openrouter.ai/api/v1/models" ;;
         groq)       echo "https://api.groq.com/openai/v1/models" ;;
         deepseek)   echo "https://api.deepseek.com/v1/models" ;;
+        opencode)   echo "https://opencode.ai/zen/v1/models" ;;
         *) return 1 ;;
     esac
     return 0
@@ -86,6 +90,7 @@ get_provider_key_vars() {
         openrouter) echo "OPENROUTER_API_KEY" ;;
         groq)       echo "GROQ_API_KEY" ;;
         deepseek)   echo "DEEPSEEK_API_KEY" ;;
+        opencode)   echo "OPENCODE_API_KEY" ;;
         *) return 1 ;;
     esac
     return 0
@@ -95,26 +100,44 @@ get_provider_key_vars() {
 is_known_provider() {
     local provider="$1"
     case "$provider" in
-        anthropic|openai|google|openrouter|groq|deepseek) return 0 ;;
+        anthropic|openai|google|openrouter|groq|deepseek|opencode) return 0 ;;
         *) return 1 ;;
     esac
 }
 
 # Tier to primary/fallback model mapping
 # Format: primary_provider/model|fallback_provider/model
+# When OpenCode is available, prefer opencode/* model IDs (routed through
+# OpenCode's gateway, no direct API keys needed for these).
 get_tier_models() {
     local tier="$1"
-    case "$tier" in
-        haiku)  echo "anthropic/claude-3-5-haiku-20241022|google/gemini-2.5-flash" ;;
-        flash)  echo "google/gemini-2.5-flash|openai/gpt-4.1-mini" ;;
-        sonnet) echo "anthropic/claude-sonnet-4-20250514|openai/gpt-4.1" ;;
-        pro)    echo "google/gemini-2.5-pro|anthropic/claude-sonnet-4-20250514" ;;
-        opus)   echo "anthropic/claude-opus-4-6|openai/o3" ;;
-        health) echo "anthropic/claude-sonnet-4-5|google/gemini-2.5-flash" ;;
-        eval)   echo "anthropic/claude-sonnet-4-5|google/gemini-2.5-flash" ;;
-        coding) echo "anthropic/claude-opus-4-6|openai/o3" ;;
-        *) return 1 ;;
-    esac
+
+    # Check if OpenCode is available (CLI installed and models cache exists)
+    if _is_opencode_available; then
+        case "$tier" in
+            haiku)  echo "opencode/claude-3-5-haiku|opencode/gemini-3-flash" ;;
+            flash)  echo "google/gemini-2.5-flash|opencode/gemini-3-flash" ;;
+            sonnet) echo "opencode/claude-sonnet-4|anthropic/claude-sonnet-4-20250514" ;;
+            pro)    echo "google/gemini-2.5-pro|opencode/gemini-3-pro" ;;
+            opus)   echo "opencode/claude-opus-4-6|anthropic/claude-opus-4-6" ;;
+            health) echo "opencode/claude-sonnet-4-5|google/gemini-2.5-flash" ;;
+            eval)   echo "opencode/claude-sonnet-4-5|google/gemini-2.5-flash" ;;
+            coding) echo "opencode/claude-opus-4-6|anthropic/claude-opus-4-6" ;;
+            *) return 1 ;;
+        esac
+    else
+        case "$tier" in
+            haiku)  echo "anthropic/claude-3-5-haiku-20241022|google/gemini-2.5-flash" ;;
+            flash)  echo "google/gemini-2.5-flash|openai/gpt-4.1-mini" ;;
+            sonnet) echo "anthropic/claude-sonnet-4-20250514|openai/gpt-4.1" ;;
+            pro)    echo "google/gemini-2.5-pro|anthropic/claude-sonnet-4-20250514" ;;
+            opus)   echo "anthropic/claude-opus-4-6|openai/o3" ;;
+            health) echo "anthropic/claude-sonnet-4-5|google/gemini-2.5-flash" ;;
+            eval)   echo "anthropic/claude-sonnet-4-5|google/gemini-2.5-flash" ;;
+            coding) echo "anthropic/claude-opus-4-6|openai/o3" ;;
+            *) return 1 ;;
+        esac
+    fi
     return 0
 }
 
@@ -127,6 +150,52 @@ is_known_tier() {
     esac
 }
 
+# =============================================================================
+# OpenCode Integration
+# =============================================================================
+# OpenCode maintains a model registry from models.dev cached at
+# ~/.cache/opencode/models.json. This provides instant model discovery
+# without needing direct API keys for each provider.
+
+_is_opencode_available() {
+    # Check if opencode CLI exists and models cache is present
+    if command -v opencode &>/dev/null && [[ -f "$OPENCODE_MODELS_CACHE" && -s "$OPENCODE_MODELS_CACHE" ]]; then
+        return 0
+    fi
+    return 1
+}
+
+# Check if a model exists in the OpenCode models cache.
+# Returns 0 if found, 1 if not.
+_opencode_model_exists() {
+    local model_spec="$1"
+    local provider model_id
+
+    if [[ "$model_spec" == *"/"* ]]; then
+        provider="${model_spec%%/*}"
+        model_id="${model_spec#*/}"
+    else
+        model_id="$model_spec"
+        provider=""
+    fi
+
+    if [[ ! -f "$OPENCODE_MODELS_CACHE" || ! -s "$OPENCODE_MODELS_CACHE" ]]; then
+        return 1
+    fi
+
+    # Check the cache JSON: providers are top-level keys, models are nested
+    if [[ -n "$provider" ]]; then
+        jq -e --arg p "$provider" --arg m "$model_id" \
+            '.[$p].models[$m] // empty' "$OPENCODE_MODELS_CACHE" >/dev/null 2>&1
+        return $?
+    else
+        # Search all providers for this model ID
+        jq -e --arg m "$model_id" \
+            '[.[] | .models[$m] // empty] | length > 0' "$OPENCODE_MODELS_CACHE" >/dev/null 2>&1
+        return $?
+    fi
+}
+
 # =============================================================================
 # Database Setup
 # =============================================================================
@@ -392,6 +461,25 @@ probe_provider() {
         fi
     fi
 
+    # OpenCode provider: check via models cache (no API key needed)
+    if [[ "$provider" == "opencode" ]]; then
+        if _is_opencode_available; then
+            local oc_models_count=0
+            oc_models_count=$(jq -r '.opencode.models | length' "$OPENCODE_MODELS_CACHE" 2>/dev/null || echo "0")
+            _record_health "opencode" "healthy" 200 0 "" "$oc_models_count"
+            [[ "$quiet" != "true" ]] && print_success "opencode: healthy ($oc_models_count models in cache)"
+            db_query "
+                INSERT INTO probe_log (provider, action, result, duration_ms, details)
+                VALUES ('opencode', 'cache_check', 'healthy', 0, '$oc_models_count models from cache');
+            " || true
+            return 0
+        else
+            _record_health "opencode" "unhealthy" 0 0 "OpenCode CLI or models cache not found" 0
+            [[ "$quiet" != "true" ]] && print_warning "opencode: CLI or models cache not available"
+            return 1
+        fi
+    fi
+
     # Resolve API key
     local key_var
     if ! key_var=$(resolve_api_key "$provider"); then
@@ -703,7 +791,14 @@ check_model_available() {
         fi
     fi
 
-    # Model-level check: query the model-registry if available
+    # Model-level check 1: OpenCode models cache (instant, preferred)
+    if _opencode_model_exists "$model_spec"; then
+        _record_model_availability "$model_id" "$provider" 1
+        [[ "$quiet" != "true" ]] && print_success "$model_spec: available (OpenCode cache confirmed)"
+        return 0
+    fi
+
+    # Model-level check 2: query the model-registry SQLite if available
     local registry_db="${AVAILABILITY_DIR}/model-registry.db"
     if [[ -f "$registry_db" ]]; then
         local in_registry
@@ -1275,8 +1370,16 @@ cmd_help() {
     echo "  eval    - Cheap evaluation model"
     echo "  coding  - Best SOTA coding model"
     echo ""
+    echo "Providers:"
+    echo "  anthropic, openai, google, openrouter, groq, deepseek, opencode"
+    echo "  The 'opencode' provider uses the OpenCode models cache (~/.cache/opencode/models.json)"
+    echo "  instead of direct API probing. When OpenCode is available, tier resolution"
+    echo "  prefers opencode/* model IDs (routed through OpenCode's gateway)."
+    echo ""
     echo "Examples:"
     echo "  model-availability-helper.sh check anthropic"
+    echo "  model-availability-helper.sh check opencode"
+    echo "  model-availability-helper.sh check opencode/claude-sonnet-4"
     echo "  model-availability-helper.sh check anthropic/claude-sonnet-4-20250514"
     echo "  model-availability-helper.sh check sonnet"
     echo "  model-availability-helper.sh probe --all"
@@ -1304,6 +1407,7 @@ cmd_help() {
     echo "  3 - API key invalid or missing"
     echo ""
     echo "Cache: $AVAILABILITY_DB"
+    echo "OpenCode models: $OPENCODE_MODELS_CACHE"
     echo "TTL: ${DEFAULT_HEALTH_TTL}s (health), ${DEFAULT_RATELIMIT_TTL}s (rate limits)"
     echo ""
     return 0
diff --git a/.agents/scripts/model-registry-helper.sh b/.agents/scripts/model-registry-helper.sh
index 8bd117ccd..d4f64770c 100755
--- a/.agents/scripts/model-registry-helper.sh
+++ b/.agents/scripts/model-registry-helper.sh
@@ -375,13 +375,127 @@ ${line}"
 }
 
 # =============================================================================
-# Sync: Provider APIs (live model discovery)
+# Sync: OpenCode Models (preferred — uses opencode CLI model registry)
 # =============================================================================
+# OpenCode maintains a model registry sourced from models.dev that includes
+# all providers the user has configured. This is faster and more reliable than
+# probing individual provider APIs directly, and works even without direct
+# API keys (OpenCode routes through its gateway for opencode/* models).
+
+sync_opencode() {
+    local added=0
+
+    # Check if opencode CLI is available
+    if ! command -v opencode &>/dev/null; then
+        print_info "OpenCode CLI not found, skipping opencode model sync"
+        return 0
+    fi
+
+    # Try the cached models file first (instant, no network)
+    local cache_file="${HOME}/.cache/opencode/models.json"
+    local model_ids=""
+
+    # Only extract models from providers we track (avoids processing 2500+ models
+    # from the full models.dev registry — we only need ~100 from relevant providers)
+    local relevant_providers='["anthropic","openai","google","openrouter","groq","deepseek","opencode"]'
+
+    if [[ -f "$cache_file" && -s "$cache_file" ]]; then
+        model_ids=$(jq -r --argjson providers "$relevant_providers" '
+            to_entries[] |
+            select(.key as $k | $providers | index($k)) |
+            .key as $provider |
+            .value.models // {} |
+            keys[] |
+            "\($provider)/\(.)"
+        ' "$cache_file" 2>/dev/null) || true
+    fi
+
+    # Fallback: use opencode models CLI if cache is empty or missing
+    if [[ -z "$model_ids" ]]; then
+        print_info "  Cache miss, querying opencode models CLI..."
+        model_ids=$(timeout "$DEFAULT_TIMEOUT" opencode models 2>/dev/null \
+            | grep -E '^(anthropic|openai|google|openrouter|groq|deepseek|opencode)/' | sort) || true
+    fi
+
+    if [[ -z "$model_ids" ]]; then
+        print_warning "No models discovered from OpenCode"
+        return 0
+    fi
+
+    # Build batch SQL for all models (much faster than individual queries)
+    local sql_batch="BEGIN TRANSACTION;"
+    while IFS= read -r full_id; do
+        [[ -z "$full_id" ]] && continue
+        # Skip non-text models (embeddings, tts, whisper, image-only)
+        case "$full_id" in
+            *embed*|*tts*|*whisper*|*dall-e*|*moderation*|*image*) continue ;;
+        esac
+
+        local provider
+        provider="${full_id%%/*}"
+
+        # Normalize provider name to match our conventions
+        local norm_provider
+        case "$provider" in
+            anthropic)  norm_provider="Anthropic" ;;
+            openai)     norm_provider="OpenAI" ;;
+            google)     norm_provider="Google" ;;
+            openrouter) norm_provider="OpenRouter" ;;
+            groq)       norm_provider="Groq" ;;
+            deepseek)   norm_provider="DeepSeek" ;;
+            opencode)   norm_provider="OpenCode" ;;
+            *)          norm_provider="$provider" ;;
+        esac
+
+        sql_batch="${sql_batch}
+            INSERT INTO provider_models (model_id, provider, in_registry, in_subagents, discovered_at)
+            VALUES (
+                '$(sql_escape "$full_id")',
+                '$(sql_escape "$norm_provider")',
+                0, 0,
+                strftime('%Y-%m-%dT%H:%M:%SZ', 'now')
+            )
+            ON CONFLICT(model_id, provider) DO UPDATE SET
+                discovered_at = excluded.discovered_at;"
+        added=$((added + 1))
+    done <<< "$model_ids"
+    sql_batch="${sql_batch} COMMIT;"
+
+    # Execute batch insert
+    db_query "$sql_batch"
+
+    db_query "
+        INSERT INTO sync_log (sync_type, source, models_added, models_updated, details)
+        VALUES ('opencode', 'opencode-models', $added, 0, 'Discovered from OpenCode model registry');
+    "
+
+    print_info "OpenCode sync: $added models discovered"
+    return 0
+}
+
+# =============================================================================
+# Sync: Provider APIs (fallback — direct API key probing)
+# =============================================================================
+# Falls back to direct API probing when OpenCode CLI is not available.
+# Requires individual provider API keys in environment.
 
 sync_providers() {
     local added=0
     local json_flag="${1:-false}"
 
+    # Skip if opencode sync already ran successfully (check sync_log)
+    local opencode_synced
+    opencode_synced=$(db_query "
+        SELECT models_added FROM sync_log
+        WHERE sync_type = 'opencode'
+        AND (julianday('now') - julianday(timestamp)) * 86400 < 60
+        ORDER BY id DESC LIMIT 1;
+    " 2>/dev/null || echo "")
+    if [[ -n "$opencode_synced" && "$opencode_synced" -gt 0 ]]; then
+        print_info "Skipping direct API probing (OpenCode sync already discovered $opencode_synced models)"
+        return 0
+    fi
+
     # Reuse provider key detection from compare-models-helper.sh
     local provider_env_keys="Anthropic|ANTHROPIC_API_KEY
 OpenAI|OPENAI_API_KEY
@@ -559,8 +673,12 @@ cmd_sync() {
     [[ "$quiet" != "true" ]] && print_info "Phase 2: Syncing embedded model data..."
     sync_embedded
 
-    # Phase 3: Sync from provider APIs (if keys available)
-    [[ "$quiet" != "true" ]] && print_info "Phase 3: Discovering models from provider APIs..."
+    # Phase 3: Sync from OpenCode model registry (preferred — fast, no API keys needed)
+    [[ "$quiet" != "true" ]] && print_info "Phase 3: Discovering models from OpenCode registry..."
+    sync_opencode
+
+    # Phase 4: Fallback to direct provider API probing (skipped if Phase 3 succeeded)
+    [[ "$quiet" != "true" ]] && print_info "Phase 4: Direct provider API discovery (fallback)..."
     sync_providers
 
     # Cleanup old backups
@@ -1154,7 +1272,8 @@ cmd_help() {
     echo "Data Sources:"
     echo "  1. Subagent frontmatter ($MODELS_DIR/*.md)"
     echo "  2. Embedded data (compare-models-helper.sh MODEL_DATA)"
-    echo "  3. Provider APIs (Anthropic, OpenAI, Google, OpenRouter, Groq, DeepSeek)"
+    echo "  3. OpenCode model registry (opencode models — preferred, from models.dev)"
+    echo "  4. Provider APIs (Anthropic, OpenAI, Google, OpenRouter, Groq, DeepSeek)"
     echo ""
     return 0
 }
diff --git a/tests/test-model-availability.sh b/tests/test-model-availability.sh
index 500a35ebd..e18a22d56 100755
--- a/tests/test-model-availability.sh
+++ b/tests/test-model-availability.sh
@@ -188,12 +188,12 @@ fi
 
 # Check with known provider (may succeed or fail depending on keys)
 # Use || true to prevent set -e from aborting on non-zero exit
-for provider in anthropic openai google; do
+for provider in anthropic openai google opencode; do
     check_exit=0
     run_with_timeout 15 bash "$HELPER" check "$provider" --quiet >/dev/null 2>&1 || check_exit=$?
     case "$check_exit" in
         0) pass "check $provider: healthy" ;;
-        1) pass "check $provider: unhealthy (expected without key)" ;;
+        1) pass "check $provider: unhealthy (expected without key or CLI)" ;;
         2) pass "check $provider: rate limited" ;;
         3) pass "check $provider: no key (expected in CI)" ;;
         *) fail "check $provider: unexpected exit code $check_exit" ;;
@@ -255,7 +255,41 @@ else
 fi
 
 # ============================================================
-# SECTION 7: JSON output
+# SECTION 7: OpenCode Integration
+# ============================================================
+section "OpenCode Integration"
+
+# Verify opencode is a known provider
+if bash "$HELPER" help 2>&1 | grep -q "opencode"; then
+    pass "help mentions opencode provider"
+else
+    fail "help mentions opencode provider"
+fi
+
+# Check opencode provider (should succeed if CLI installed, fail gracefully otherwise)
+check_oc_exit=0
+run_with_timeout 10 bash "$HELPER" check opencode --quiet >/dev/null 2>&1 || check_oc_exit=$?
+case "$check_oc_exit" in
+    0) pass "check opencode: healthy (CLI and cache available)" ;;
+    1) pass "check opencode: unhealthy (CLI or cache not available)" ;;
+    *) fail "check opencode: unexpected exit code $check_oc_exit" ;;
+esac
+
+# Verify opencode model check (if opencode is available)
+if command -v opencode &>/dev/null && [[ -f "$HOME/.cache/opencode/models.json" ]]; then
+    oc_model_exit=0
+    run_with_timeout 10 bash "$HELPER" check "opencode/claude-sonnet-4" --quiet >/dev/null 2>&1 || oc_model_exit=$?
+    case "$oc_model_exit" in
+        0) pass "check opencode/claude-sonnet-4: available" ;;
+        1) pass "check opencode/claude-sonnet-4: not available (provider unhealthy)" ;;
+        *) fail "check opencode/claude-sonnet-4: unexpected exit code $oc_model_exit" ;;
+    esac
+else
+    skip "opencode model check (opencode CLI not installed)"
+fi
+
+# ============================================================
+# SECTION 8: JSON output
 # ============================================================
 section "JSON Output"