diff --git a/internal/app/doctor.go b/internal/app/doctor.go
index 26a2ec7..341e2eb 100644
--- a/internal/app/doctor.go
+++ b/internal/app/doctor.go
@@ -64,6 +64,7 @@ func runDoctor(opts runOptions) error {
 	results = append(results, checkAgentsMDSize(repoRoot))
 	results = append(results, checkREADMESkillInventory(repoRoot))
 	results = append(results, checkMemsearchIndex(home))
+	results = append(results, checkHerdrPluginHealth())
 	results = append(results, checkExternalPackageAge(repoRoot, cfg, opts.SkipPackageAge, timeNow()))
 	results = append(results, checkExternalSkillSources(cfg, home))
 	results = append(results, checkMaterializedExternalSkills(repoRoot, cfg, home))
diff --git a/internal/app/doctor_herdr.go b/internal/app/doctor_herdr.go
new file mode 100644
index 0000000..a7e0661
--- /dev/null
+++ b/internal/app/doctor_herdr.go
@@ -0,0 +1,186 @@
+package app
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strings"
+)
+
+type herdrPluginCommand struct {
+	Command   []string `json:"command"`
+	Platforms []string `json:"platforms"`
+}
+
+type herdrPlugin struct {
+	PluginID   string               `json:"plugin_id"`
+	PluginRoot string               `json:"plugin_root"`
+	Actions    []herdrPluginCommand `json:"actions"`
+	Events     []herdrPluginCommand `json:"events"`
+	Panes      []herdrPluginCommand `json:"panes"`
+}
+
+type herdrPluginListResponse struct {
+	Result struct {
+		Plugins []herdrPlugin `json:"plugins"`
+	} `json:"result"`
+}
+
+type herdrPluginLog struct {
+	PluginID     string   `json:"plugin_id"`
+	Command      []string `json:"command"`
+	Status       string   `json:"status"`
+	Error        string   `json:"error"`
+	Stderr       string   `json:"stderr"`
+	LogID        string   `json:"log_id"`
+	StartedUnixM int64    `json:"started_unix_ms"`
+}
+
+type herdrPluginLogResponse struct {
+	Result struct {
+		Logs []herdrPluginLog `json:"logs"`
+	} `json:"result"`
+}
+
+type executableLookup func(string) (string, error)
+
+func checkHerdrPluginHealth() checkResult {
+	if os.Getenv("HERDR_ENV") != "1" {
+		return checkResult{"herdr plugins", checkStatusPass, "not running inside Herdr, skipped"}
+	}
+	herdr, err := exec.LookPath("herdr")
+	if err != nil {
+		return checkResult{"herdr plugins", checkStatusWarn, "Herdr session detected but herdr CLI is not on PATH"}
+	}
+
+	pluginData, err := exec.Command(herdr, "plugin", "list", "--json").Output()
+	if err != nil {
+		return checkResult{"herdr plugins", checkStatusWarn, fmt.Sprintf("cannot inspect installed plugins: %v", err)}
+	}
+	logData, err := exec.Command(herdr, "plugin", "log", "list").Output()
+	if err != nil {
+		return checkResult{"herdr plugins", checkStatusWarn, fmt.Sprintf("cannot inspect plugin command logs: %v", err)}
+	}
+
+	var plugins herdrPluginListResponse
+	if err := json.Unmarshal(pluginData, &plugins); err != nil {
+		return checkResult{"herdr plugins", checkStatusWarn, fmt.Sprintf("cannot parse plugin inventory: %v", err)}
+	}
+	var logs herdrPluginLogResponse
+	if err := json.Unmarshal(logData, &logs); err != nil {
+		return checkResult{"herdr plugins", checkStatusWarn, fmt.Sprintf("cannot parse plugin command logs: %v", err)}
+	}
+	return assessHerdrPluginHealth(plugins.Result.Plugins, logs.Result.Logs, exec.LookPath)
+}
+
+func assessHerdrPluginHealth(plugins []herdrPlugin, logs []herdrPluginLog, lookup executableLookup) checkResult {
+	latest := make(map[string]herdrPluginLog)
+	for _, log := range logs {
+		key := herdrCommandKey(log.PluginID, log.Command)
+		if prior, ok := latest[key]; !ok || log.StartedUnixM > prior.StartedUnixM {
+			latest[key] = log
+		}
+	}
+
+	var issues []string
+	for _, plugin := range plugins {
+		commands := append([]herdrPluginCommand{}, plugin.Actions...)
+		commands = append(commands, plugin.Events...)
+		commands = append(commands, plugin.Panes...)
+		for _, declared := range commands {
+			if len(declared.Command) == 0 || !herdrCommandApplies(declared.Platforms, runtime.GOOS) {
+				continue
+			}
+			missingPath := missingHerdrCommandPath(plugin.PluginRoot, declared.Command)
+			if missingPath != "" {
+				issues = append(issues, fmt.Sprintf("%s declares missing command file %s; reinstall or update the plugin", plugin.PluginID, missingPath))
+				continue
+			}
+			executable := declared.Command[0]
+			if !strings.ContainsRune(executable, filepath.Separator) {
+				if _, err := lookup(executable); err != nil {
+					issues = append(issues, fmt.Sprintf("%s requires executable %q but doctor cannot resolve it; install it or use an absolute executable path in the plugin manifest", plugin.PluginID, executable))
+					continue
+				}
+			}
+
+			log, ok := latest[herdrCommandKey(plugin.PluginID, declared.Command)]
+			if !ok || log.Status != "failed" {
+				continue
+			}
+			if strings.Contains(strings.ToLower(log.Error), "no such file or directory") {
+				if !strings.ContainsRune(executable, filepath.Separator) {
+					if resolved, err := lookup(executable); err == nil {
+						issues = append(issues, fmt.Sprintf("%s cannot start %q from the Herdr server PATH although doctor resolves it at %s; use that absolute executable in the plugin manifest or restart Herdr with its directory on PATH", plugin.PluginID, executable, resolved))
+						continue
+					}
+				}
+				issues = append(issues, fmt.Sprintf("%s cannot start %q; install it or use an absolute executable path in the plugin manifest", plugin.PluginID, executable))
+				continue
+			}
+			detail := strings.TrimSpace(log.Error)
+			if detail == "" {
+				detail = strings.TrimSpace(log.Stderr)
+			}
+			if detail == "" {
+				detail = "command failed"
+			}
+			issues = append(issues, fmt.Sprintf("%s latest command log %s failed: %s", plugin.PluginID, log.LogID, detail))
+		}
+	}
+
+	if len(issues) > 0 {
+		sort.Strings(issues)
+		return checkResult{"herdr plugins", checkStatusWarn, strings.Join(issues, "; ")}
+	}
+	return checkResult{"herdr plugins", checkStatusPass, fmt.Sprintf("%d installed plugins have valid commands and no current command failures", len(plugins))}
+}
+
+func herdrCommandApplies(platforms []string, goos string) bool {
+	if len(platforms) == 0 {
+		return true
+	}
+	if goos == "darwin" {
+		goos = "macos"
+	}
+	for _, platform := range platforms {
+		if platform == goos {
+			return true
+		}
+	}
+	return false
+}
+
+func herdrCommandKey(pluginID string, command []string) string {
+	return pluginID + "\x00" + strings.Join(command, "\x00")
+}
+
+func missingHerdrCommandPath(pluginRoot string, command []string) string {
+	for i, token := range command {
+		if i == 0 && !hasHerdrPathSeparator(token) {
+			continue
+		}
+		if strings.HasPrefix(token, "-") || strings.ContainsAny(token, " \t\n\r$\"'`") || (!strings.HasPrefix(token, ".") && !hasHerdrPathSeparator(token)) {
+			continue
+		}
+		candidate := token
+		if !filepath.IsAbs(candidate) {
+			candidate = filepath.Join(pluginRoot, candidate)
+		}
+		if _, err := os.Stat(candidate); os.IsNotExist(err) {
+			return candidate
+		}
+	}
+	return ""
+}
+
+// hasHerdrPathSeparator accepts both slash forms. A Windows plugin manifest may
+// still write "bin/hook.exe" even though filepath.Separator is a backslash
+// there, and such a command must not be reported as healthy.
+func hasHerdrPathSeparator(token string) bool {
+	return strings.ContainsAny(token, `/\`)
+}
diff --git a/internal/app/doctor_herdr_test.go b/internal/app/doctor_herdr_test.go
new file mode 100644
index 0000000..8642066
--- /dev/null
+++ b/internal/app/doctor_herdr_test.go
@@ -0,0 +1,137 @@
+package app
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestAssessHerdrPluginHealthDiagnosesServerPATHMismatch(t *testing.T) {
+	root := t.TempDir()
+	if err := os.MkdirAll(filepath.Join(root, "src"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "src", "hook.js"), []byte("// hook\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	command := []string{"node", "src/hook.js"}
+	plugins := []herdrPlugin{{
+		PluginID:   "heeler",
+		PluginRoot: root,
+		Events:     []herdrPluginCommand{{Command: command}},
+	}}
+	logs := []herdrPluginLog{{
+		PluginID:     "heeler",
+		Command:      command,
+		Status:       "failed",
+		Error:        "No such file or directory (os error 2)",
+		StartedUnixM: 10,
+	}}
+
+	result := assessHerdrPluginHealth(plugins, logs, func(name string) (string, error) {
+		if name == "node" {
+			return "/home/test/.local/bin/node", nil
+		}
+		return "", errors.New("not found")
+	})
+	if result.status != checkStatusWarn {
+		t.Fatalf("status = %q, want warn (%s)", result.status, result.detail)
+	}
+	for _, want := range []string{"Herdr server PATH", "/home/test/.local/bin/node", "absolute executable"} {
+		if !strings.Contains(result.detail, want) {
+			t.Fatalf("detail %q does not contain %q", result.detail, want)
+		}
+	}
+}
+
+func TestAssessHerdrPluginHealthIgnoresRecoveredFailure(t *testing.T) {
+	root := t.TempDir()
+	if err := os.MkdirAll(filepath.Join(root, "src"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "src", "hook.js"), []byte("// hook\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	executable := filepath.Join(root, "node")
+	if err := os.WriteFile(executable, []byte("#!/bin/sh\n"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	command := []string{executable, "src/hook.js"}
+	plugins := []herdrPlugin{{
+		PluginID:   "heeler",
+		PluginRoot: root,
+		Events:     []herdrPluginCommand{{Command: command}},
+	}}
+	logs := []herdrPluginLog{
+		{PluginID: "heeler", Command: command, Status: "failed", Error: "old failure", StartedUnixM: 10},
+		{PluginID: "heeler", Command: command, Status: "succeeded", StartedUnixM: 20},
+	}
+
+	result := assessHerdrPluginHealth(plugins, logs, func(string) (string, error) { return "", nil })
+	if result.status != checkStatusPass {
+		t.Fatalf("status = %q, want pass (%s)", result.status, result.detail)
+	}
+}
+
+func TestHerdrCommandAppliesUsesManifestPlatformNames(t *testing.T) {
+	if !herdrCommandApplies([]string{"macos"}, "darwin") {
+		t.Fatal("macos command should apply on darwin")
+	}
+	if herdrCommandApplies([]string{"windows"}, "darwin") {
+		t.Fatal("windows command should not apply on darwin")
+	}
+}
+
+func TestAssessHerdrPluginHealthIgnoresInlineShellProgram(t *testing.T) {
+	root := t.TempDir()
+	command := []string{"bash", "-lc", `exec "$HERDR_PLUGIN_ROOT/bin/plugin"`}
+	plugins := []herdrPlugin{{
+		PluginID:   "shell-plugin",
+		PluginRoot: root,
+		Actions:    []herdrPluginCommand{{Command: command}},
+	}}
+
+	result := assessHerdrPluginHealth(plugins, nil, func(string) (string, error) {
+		return "/bin/bash", nil
+	})
+	if result.status != checkStatusPass {
+		t.Fatalf("status = %q, want pass (%s)", result.status, result.detail)
+	}
+}
+
+func TestAssessHerdrPluginHealthReportsMissingHookFile(t *testing.T) {
+	root := t.TempDir()
+	command := []string{"node", "src/missing-hook.js"}
+	plugins := []herdrPlugin{{
+		PluginID:   "broken-plugin",
+		PluginRoot: root,
+		Events:     []herdrPluginCommand{{Command: command}},
+	}}
+
+	result := assessHerdrPluginHealth(plugins, nil, func(string) (string, error) {
+		return "/usr/bin/node", nil
+	})
+	if result.status != checkStatusWarn {
+		t.Fatalf("status = %q, want warn (%s)", result.status, result.detail)
+	}
+	for _, want := range []string{"missing command file", "reinstall or update"} {
+		if !strings.Contains(result.detail, want) {
+			t.Fatalf("detail %q does not contain %q", result.detail, want)
+		}
+	}
+}
+
+func TestMissingHerdrCommandPathRecognizesWindowsStyleSeparators(t *testing.T) {
+	root := t.TempDir()
+	if got := missingHerdrCommandPath(root, []string{"node", "bin/missing-hook.js"}); got == "" {
+		t.Fatal("forward-slash relative path was not recognized as a path")
+	}
+	if got := missingHerdrCommandPath(root, []string{`C:/plugin/bin/missing-hook.exe`}); got == "" {
+		t.Fatal("windows-style absolute path was not recognized as a path")
+	}
+	if got := missingHerdrCommandPath(root, []string{"node", "-e", "console.log(1)"}); got != "" {
+		t.Fatalf("inline program reported a missing path: %q", got)
+	}
+}