fix: reuse one TTYApprover per process in CLI mode (M-13) (#70)

shell and parallel_shell created a fresh TTYApprover for every prompt,
so the friction counter and trust cache were reset each time and the
post-3-approvals friction mode never engaged.

Changes:
- cmd/odek/shell.go: promptUser now stores the created TTYApprover in
  t.approver and reuses it on subsequent prompts.
- cmd/odek/perf_tools.go: same for parallelShellTool.promptCommand.
- Added TestShellTool_PromptUser_ReusesTTYApprover.
- Updated docs/SECURITY.md and AGENTS.md.

Author: jkyberneees

AGENTS.md

@@ -112,7 +112,7 @@ Layered prompt-injection / approval-fatigue defenses. Full reference: [docs/SECU
 - **Skill provenance gate** (`internal/skills/loader.go` + `cache.go` + `tools.go`) — `Skill.Provenance{Untrusted, Sources, NeedsReview}`. NeedsReview skills pin to Lazy regardless of `auto_load`. The auto-save path declines tainted suggestions by default. Agent-created skills via `skill_save` and patched skills via `skill_patch` are forced to `Untrusted` + `NeedsReview`, and `skill_patch` refuses edits that touch the YAML frontmatter, blocking an injected agent from flipping `auto_load` or clearing `needs_review`. `odek skill promote <name> --force` clears the flag after explicit user review.
 - **Sub-agent damage cap** (`cmd/odek/subagent.go::applySubagentTrust`) — `delegate_tasks` carries `trust_level` + `max_risk`. Untrusted ⇒ NonInteractive=deny, Destructive/CodeExec/Install/SystemWrite/NetworkEgress all forced to Deny. `max_risk` ⇒ everything above cap forced to Deny.
 - **FD-based API key handoff** (`cmd/odek/subagent_key.go`) — parent writes key to a 0600 tempfile, immediately `unlink()`s, passes the FD via `cmd.ExtraFiles`. Sub-agent reads from `$ODEK_API_KEY_FD` and closes. Key never in `/proc/<pid>/environ`.
-- **Approver friction** (`internal/danger/approver.go`, `cmd/odek/wsapprover.go`) — both TTYApprover and WSApprover engage friction mode after 3 approvals of the same class in 60s: require typing literal `approve`, 1.5s pause. Trust-class shortcut disabled for `destructive` + `blocked` regardless.
+- **Approver friction** (`internal/danger/approver.go`, `cmd/odek/wsapprover.go`, `cmd/odek/shell.go`, `cmd/odek/perf_tools.go`) — both TTYApprover and WSApprover engage friction mode after 3 approvals of the same class in 60s: require typing literal `approve`, 1.5s pause. Trust-class shortcut disabled for `destructive` + `blocked` regardless. CLI `shell`/`parallel_shell` reuse a single TTYApprover instance per process so the counter and trust cache persist across prompts.
 - **Danger classifier bypass resistance** (`internal/danger/classifier.go`) — `normalize()` pre-processes: expand `$IFS` / `${IFS}`, extract `$(...)` / `` `...` `` substitutions, strip `command` / `exec` / `builtin` wrappers, collapse unquoted backslashes, basename absolute paths. `awk`/`gawk`, `sed` (`e` command / `-f`), and editors (`vi`/`vim`/`nvim`/`emacs`/`ed`/`ex`) are classified as `code_execution` when given a script or file operand, closing `awk 'BEGIN{system(...)}'`, `sed 's///e'`, and editor `!` shell escapes. `rm -rf ./` / `rm -rf ./..` are normalised to `.` / `..` for wipe-target matching, and `${VAR:--rf}` default-value flag substitutions are treated as fail-closed. Regression suite in `classifier_bypass_test.go`.
 - **WebSocket CSRF token** (`cmd/odek/serve.go`) — `odek serve` issues a random 256-bit token at startup and requires it on `/ws` via cookie, `X-Odek-Ws-Token` header, or `odek.<token>` subprotocol. The token is no longer embedded in every `GET /` response; it is only delivered when the request includes the correct `?token=` query parameter (Jupyter-style), and a non-loopback bind prints a loud warning. The localhost origin check remains as defense-in-depth.
 - **SSRF / DNS-rebinding dial guard** (`cmd/odek/ssrf_guard.go` + `internal/danger/classifier.go`) — `browser`, `http_batch`, and `web_search` resolve hostnames at dial time and refuse internal IPs (loopback, RFC1918, RFC4193, link-local, RFC 6598 CGNAT `100.64.0.0/10`, RFC 2544 benchmark `198.18.0.0/15`, and unspecified), then pin the dial to the validated IP. Operator-configured backends (e.g. `web_search.base_url`) are added to an allowlist so container-internal services such as SearXNG remain reachable.

cmd/odek/perf_tools.go

@@ -444,19 +444,22 @@ func (t *parallelShellTool) Call(argsJSON string) (result string, err error) {
 // parallel_shell cannot bypass interactive approval when no explicit approver
 // is injected.
 func (t *parallelShellTool) promptCommand(cls danger.RiskClass, cmd, description string) error {
+	// Reuse a single TTYApprover per tool instance so the friction counter
+	// and trust cache survive across multiple prompts.
+	t.trustedMu.Lock()
 	approver := t.approver
 	if approver == nil {
 		ttyApprover := danger.NewTTYApprover(&t.dangerousConfig)
-		t.trustedMu.Lock()
 		if t.trustedClasses != nil {
 			ttyApprover.SetTrustedClasses(t.trustedClasses)
 		}
-		t.trustedMu.Unlock()
 		if t.ttyPath != "" {
 			ttyApprover.TTYPath = t.ttyPath
 		}
+		t.approver = ttyApprover
 		approver = ttyApprover
 	}
+	t.trustedMu.Unlock()
 
 	err := approver.PromptCommand(cls, cmd, description)
 	if err == nil {

cmd/odek/shell.go

@@ -251,20 +251,22 @@ func (t *shellTool) checkApproval(cmd, description string) error {
 func (t *shellTool) promptUser(cmd, description string) error {
 	cls := danger.Classify(cmd)
 
-	// Get or create the approver
+	// Get or create the approver. Reuse a single TTYApprover per tool instance
+	// so the friction counter and trust cache survive across multiple prompts.
+	t.trustedMu.Lock()
 	approver := t.approver
 	if approver == nil {
 		ttyApprover := danger.NewTTYApprover(&t.dangerousConfig)
-		t.trustedMu.Lock()
 		if t.trustedClasses != nil {
 			ttyApprover.SetTrustedClasses(t.trustedClasses)
 		}
-		t.trustedMu.Unlock()
 		if t.ttyPath != "" {
 			ttyApprover.TTYPath = t.ttyPath
 		}
+		t.approver = ttyApprover
 		approver = ttyApprover
 	}
+	t.trustedMu.Unlock()
 
 	err := approver.PromptCommand(cls, cmd, description)
 	if err == nil {

cmd/odek/shell_test.go

@@ -5,9 +5,12 @@ import (
 	"encoding/json"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/BackendStack21/odek/internal/danger"
 )
 
 func TestShellTool_Name(t *testing.T) {
@@ -388,3 +391,38 @@ func stringSlicesEqual(a, b []string) bool {
 	}
 	return true
 }
+
+func TestShellTool_PromptUser_ReusesTTYApprover(t *testing.T) {
+	dir := t.TempDir()
+	ttyPath := filepath.Join(dir, "tty")
+	// Two approval lines; friction threshold is 3, so both non-friction
+	// prompts accept the single-letter "a" shortcut.
+	if err := os.WriteFile(ttyPath, []byte("a\na\n"), 0644); err != nil {
+		t.Fatalf("write tty input: %v", err)
+	}
+
+	st := &shellTool{
+		dangerousConfig: danger.DangerousConfig{
+			Classes: map[danger.RiskClass]danger.Action{
+				danger.NetworkEgress: danger.Prompt,
+			},
+		},
+		ttyPath: ttyPath,
+	}
+
+	cmd := "curl http://example.com"
+	if err := st.promptUser(cmd, "test"); err != nil {
+		t.Fatalf("first prompt failed: %v", err)
+	}
+	first := st.approver
+	if first == nil {
+		t.Fatal("first prompt did not create an approver")
+	}
+
+	if err := st.promptUser(cmd, "test"); err != nil {
+		t.Fatalf("second prompt failed: %v", err)
+	}
+	if st.approver != first {
+		t.Error("promptUser created a new TTYApprover instead of reusing the existing one")
+	}
+}

docs/SECURITY.md

@@ -139,6 +139,7 @@ Both:
 
 - Disable the "Trust class for session" shortcut for `destructive` and `blocked`. A forged or stale UI that sends `"trust"` for those classes is coerced to a single approve.
 - Engage **friction mode** after 3 approvals of the same class in 60 s: require typing the literal word `approve` (no single-letter / button shortcut) and impose a 1.5 s pause before accepting input. This breaks reflex click-through under sustained LLM-driven approval pressure.
+- In CLI mode, the `shell` and `parallel_shell` tools reuse a single `TTYApprover` instance per process, so the friction counter and trust cache persist across prompts. Previously each prompt created a fresh approver, disabling friction entirely.
 - Default to `non_interactive: deny` for sub-agents and any context without a TTY (configurable).
 
 ### 5. Memory taint tracking