diff --git a/internal/agent/playbook.go b/internal/agent/playbook.go
index a248e8387..d2e42fd59 100644
--- a/internal/agent/playbook.go
+++ b/internal/agent/playbook.go
@@ -117,20 +117,28 @@ func (pb *Playbook) save() {
 // classifyTaskType determines the task category from the user prompt.
 // Order matters: more specific categories are checked first to avoid
 // misclassification (e.g., "add test" should be "test" not "feature").
+// Keywords are matched on word boundaries (#2745): bare substring matching
+// classified "upgrade to the latest version" as test (laTEST), "refactor
+// the contest module" as test (conTEST), "address the failing build" as
+// feature (ADDRESS), and "rebuild the parser" as build (REBUILD) - the
+// misclassified type then polluted the persisted playbook fingerprint and
+// system prompt injection. Keywords written with an explicit leading or
+// trailing space (" fail", "make ", "ci ", "new ") already encode their
+// own anchoring and keep the substring behavior.
 func classifyTaskType(userPrompt string) string {
 	p := strings.ToLower(userPrompt)
 	switch {
-	case containsAny(p, "test", "spec", "coverage", "mock"):
+	case containsAnyWord(p, "test", "spec", "coverage", "mock"):
 		return "test"
-	case containsAny(p, "build", "compile", "make ", "ci ", "deploy", "release", "publish"):
+	case containsAnyWord(p, "build", "compile", "make ", "ci ", "deploy", "release", "publish"):
 		return "build"
-	case containsAny(p, "fix", "bug", "error", "crash", "broken", " fail", "panic", "traceback"):
+	case containsAnyWord(p, "fix", "bug", "error", "crash", "broken", " fail", "panic", "traceback"):
 		return "bugfix"
-	case containsAny(p, "refactor", "clean", "rename", "reorganize", "simplify", "extract"):
+	case containsAnyWord(p, "refactor", "clean", "rename", "reorganize", "simplify", "extract"):
 		return "refactor"
-	case containsAny(p, "review", "check", "audit", "inspect", "scan", "analyze"):
+	case containsAnyWord(p, "review", "check", "audit", "inspect", "scan", "analyze"):
 		return "review"
-	case containsAny(p, "add", "implement", "create", "new ", "support"):
+	case containsAnyWord(p, "add", "implement", "create", "new ", "support"):
 		return "feature"
 	default:
 		return "other"
@@ -428,6 +436,45 @@ func containsAny(s string, substrs ...string) bool {
 	return false
 }
 
+// containsAnyWord matches whole words only (#2745). A keyword containing
+// an explicit space (" fail", "make ", "new ") encodes its own anchoring
+// and falls back to substring matching, preserving the original intent.
+func containsAnyWord(s string, keywords ...string) bool {
+	for _, kw := range keywords {
+		if strings.ContainsAny(kw, " \t") {
+			if strings.Contains(s, kw) {
+				return true
+			}
+			continue
+		}
+		start := 0
+		for {
+			i := strings.Index(s[start:], kw)
+			if i < 0 {
+				break
+			}
+			at := start + i
+			end := at + len(kw)
+			if wordBoundaryAt(s, at) && wordBoundaryAt(s, end) {
+				return true
+			}
+			start = at + 1
+		}
+	}
+	return false
+}
+
+// wordBoundaryAt reports whether position i in s is a word boundary:
+// either string edge, or the neighboring bytes are not word bytes on both
+// sides of the boundary. Reuses isWordByte from success_declare.go
+// (identifier semantics: [a-z0-9_]).
+func wordBoundaryAt(s string, i int) bool {
+	if i <= 0 || i >= len(s) {
+		return true
+	}
+	return !isWordByte(s[i-1]) || !isWordByte(s[i])
+}
+
 func randomID() string {
 	b := make([]byte, 6)
 	rand.Read(b)
diff --git a/internal/agent/zz_issue2745_test.go b/internal/agent/zz_issue2745_test.go
new file mode 100644
index 000000000..90d1c6e4a
--- /dev/null
+++ b/internal/agent/zz_issue2745_test.go
@@ -0,0 +1,54 @@
+package agent
+
+// #2745 regression: classifyTaskType must match keywords on word
+// boundaries - bare substring matching misclassified prompts whose words
+// merely CONTAIN a keyword (laTEST, conTEST, ADDRESS, REBUILD,
+// CHECKlist), polluting the persisted playbook fingerprint and system
+// prompt injection downstream.
+
+import "testing"
+
+func TestIssue2745_ClassifyTaskTypeWordBoundary(t *testing.T) {
+	cases := []struct {
+		prompt, want string
+	}{
+		// The five issue scenarios: substring false-positives are gone.
+		// (Category per current switch precedence - the fix removes the WRONG
+		// hit; sentences with no whole keyword left classify "other".)
+		{"Upgrade the dependency to the latest version", "other"}, // was test (la-test)
+		{"Refactor the contest scoring module", "refactor"},       // was test (con-test)
+		{"Create a checklist for onboarding", "feature"},          // was review (check)
+		{"Address the failing build", "build"},                    // was feature (add-ress); whole-word "build" wins by precedence
+		{"rebuild the parser", "other"},                           // was build (re-build); no whole keyword left
+		// Boundary sanity: real keywords at word edges still classify.
+		{"run the test suite", "test"},
+		{"tests are failing", "bugfix"}, // "test" lacks a boundary inside "tests"; space-anchored " fail" hits bugfix
+		{"fix the login bug", "bugfix"},
+		{"build the project", "build"},
+		{"deploy to prod", "build"},
+		{"review this diff", "review"},
+		{"check the logs", "review"},
+		{"add a settings page", "feature"},
+		{"create a new module", "feature"},
+		{"refactor the store", "refactor"},
+	}
+	for _, tc := range cases {
+		if got := classifyTaskType(tc.prompt); got != tc.want {
+			t.Errorf("classifyTaskType(%q) = %q, want %q", tc.prompt, got, tc.want)
+		}
+	}
+}
+
+func TestIssue2745_SpaceAnchoredKeywordsKeepSubstringSemantics(t *testing.T) {
+	// Keywords written with explicit spaces (" fail", "make ", "ci ",
+	// "new ") encode their own anchoring and keep substring behavior.
+	if got := classifyTaskType("the daemon will fail soon"); got != "bugfix" {
+		t.Errorf("space-anchored ' fail' must still match bugfix, got %q", got)
+	}
+	if got := classifyTaskType("run make all"); got != "build" {
+		t.Errorf("space-anchored 'make ' must still match build, got %q", got)
+	}
+	if got := classifyTaskType("new feature request"); got != "feature" {
+		t.Errorf("space-anchored 'new ' must still match feature, got %q", got)
+	}
+}