fix(tool-result): exempt retrieval tools from spill to prevent read-back recursion

mateclaw-server/src/main/java/vip/mate/agent/graph/executor/ToolResultProperties.java

@@ -2,6 +2,9 @@ package vip.mate.agent.graph.executor;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
 
+import java.util.List;
+import java.util.Set;
+
 /**
  * Configuration for the tool-result three-layer budget (RFC-008 Phase 3).
  *
@@ -51,6 +54,18 @@ public class ToolResultProperties {
      */
     private String storageBaseDir = "";
 
+    /**
+     * Tools whose results must NEVER be spilled. These are the tools the agent
+     * uses to <i>retrieve</i> spilled content — spilling their output would
+     * cause infinite recursion (read spill path → produces another spill →
+     * agent reads new spill → …) and starve {@code MAX_TOOL_CALLS_PER_STEP}.
+     *
+     * <p>Defaults to file-read tools that already cap their own output internally.
+     * Configurable so deployments can add more retrieval-style tools (e.g.,
+     * MCP-provided readers) without code changes.</p>
+     */
+    private List<String> excludedTools = List.of("read_file", "read_workspace_memory_file");
+
     public boolean isEnabled() { return enabled; }
     public void setEnabled(boolean enabled) { this.enabled = enabled; }
 
@@ -73,4 +88,14 @@ public class ToolResultProperties {
     public void setStorageBaseDir(String storageBaseDir) {
         this.storageBaseDir = storageBaseDir == null ? "" : storageBaseDir;
     }
+
+    public List<String> getExcludedTools() { return excludedTools; }
+    public void setExcludedTools(List<String> excludedTools) {
+        this.excludedTools = excludedTools == null ? List.of() : excludedTools;
+    }
+
+    /** O(1) membership test for the exclusion list, used on every tool result. */
+    public Set<String> excludedToolsSet() {
+        return Set.copyOf(excludedTools);
+    }
 }

mateclaw-server/src/main/java/vip/mate/agent/graph/executor/ToolResultStorage.java

@@ -52,9 +52,29 @@ public class ToolResultStorage {
     public static final String SPILL_MARKER_PREFIX = "[mate-tool-result-spill]";
 
     private final ToolResultProperties props;
+    /** Cached at construction; refreshed lazily if the underlying list mutates (rare). */
+    private volatile java.util.Set<String> excludedToolsSnapshot;
 
     public ToolResultStorage(ToolResultProperties props) {
         this.props = props;
+        this.excludedToolsSnapshot = props.excludedToolsSet();
+    }
+
+    /**
+     * Returns true when {@code toolName} is in the configured exclusion list.
+     * Excluded tools (typically retrieval tools like {@code read_file}) are
+     * never spilled — spilling their output would create a recursion where
+     * the agent reads a spill path and produces yet another spill.
+     */
+    private boolean isExcluded(String toolName) {
+        if (toolName == null) return false;
+        java.util.Set<String> snap = excludedToolsSnapshot;
+        java.util.Set<String> live = props.excludedToolsSet();
+        if (live != snap && !live.equals(snap)) {
+            this.excludedToolsSnapshot = live;
+            snap = live;
+        }
+        return snap.contains(toolName);
     }
 
     /**
@@ -73,6 +93,10 @@ public class ToolResultStorage {
         if (!props.isEnabled() || result == null) {
             return result;
         }
+        if (isExcluded(toolName)) {
+            // Retrieval-style tool — never spill, would cause read-back recursion.
+            return result;
+        }
         if (result.length() <= props.getPerResultThresholdChars()) {
             return result;
         }
@@ -115,20 +139,25 @@ public class ToolResultStorage {
         List<ToolResponseMessage.ToolResponse> mutable = new ArrayList<>(responses);
 
         while (aggregate > budget) {
-            // Find the largest response that has not yet been spilled.
+            // Find the largest response that has not yet been spilled and is
+            // not produced by an excluded (retrieval-style) tool.
             int targetIdx = -1;
             int targetLen = -1;
             for (int i = 0; i < mutable.size(); i++) {
-                String body = mutable.get(i).responseData();
+                ToolResponseMessage.ToolResponse r = mutable.get(i);
+                String body = r.responseData();
                 if (body == null || body.startsWith(SPILL_MARKER_PREFIX)) continue;
+                if (isExcluded(r.name())) continue;     // retrieval tools must not be spilled
                 if (body.length() > targetLen) {
                     targetLen = body.length();
                     targetIdx = i;
                 }
             }
             if (targetIdx < 0) {
-                // Nothing left to spill; aggregate is already as small as we can make it.
+                // Nothing left to spill; remaining oversize is from excluded tools or
-                log.warn("[ToolResultStorage] aggregate still {} chars after spilling everything eligible",
+                // already-spilled responses. Accept the over-budget state — better than
+                // breaking the agent's retrieval path.
+                log.warn("[ToolResultStorage] aggregate still {} chars after spilling everything eligible (excluded tools may push past budget)",
                         aggregate);
                 break;
             }

mateclaw-server/src/main/resources/application.yml

@@ -162,6 +162,14 @@ mate:
       per-turn-budget-chars: 16000
       preview-head-chars: 800
       storage-base-dir: ""
+      # Retrieval-style tools that must NEVER be spilled. Spilling read_file's
+      # output causes a recursion: the agent reads the spill path, that read also
+      # exceeds the threshold, gets spilled to a new path, agent reads that one,
+      # ad infinitum until MAX_TOOL_CALLS_PER_STEP is hit. Add MCP-provided
+      # readers here if they have the same role.
+      excluded-tools:
+        - read_file
+        - read_workspace_memory_file
     conversation:
       window:
         # 测试时临时调低：2000 token ≈ 2000 中文字，3 轮对话即可触发压缩