secrets: keep a masked tool secret only for its saved destination

As for the MCP env (#213), a placeholder in a custom tool's exec keeps the
stored header, proxy or body only while the url (exact string) and the kind
are unchanged. A changed or emptied url, or a kind change, with a resolved
placeholder is refused (400 on the API and the test endpoint, a tool error
for update_custom_tool) before any write and before the test request is
sent. An explicit value with a new url is allowed.

README.md

@@ -181,8 +181,9 @@ gunzip -c backups/artex-db-<timestamp>.sql.gz | docker compose exec -T postgres
   psql -U "$POSTGRES_USER" -d "$POSTGRES_DB"
 ```
 
-Stored secrets (LLM API keys, MCP env, task credentials, notification channel
-config) are encrypted in the database with the key in `keys/secret.key`
+Stored secrets (LLM API keys and proxies, MCP env, task credentials,
+notification channel config, the Brave and Tavily search keys, the web search
+and global proxies, the execution spec of custom tools) are encrypted in the database with the key in `keys/secret.key`
 (generated at first start, mode 0600, next to `jwt.key`). **A database backup
 without that key can no longer restore those secrets**: back up `keys/` with the
 dump, separately. Deployments without a persistent disk set `ARTEX_SECRET_KEY`

db/config.go

@@ -107,7 +107,10 @@ func scanProfile(sc interface{ Scan(...any) error }, into *string, p *LLMProfile
 		&p.Retry.Stream.Attempts, &p.Retry.Stream.IntervalMS,
 		&p.PriceInputPerM, &p.PriceOutputPerM, &p.PriceCacheReadPerM, &p.PriceCacheWritePerM,
 		&p.UserAgent)
-	if err != nil || into != &p.APIKey {
+	if err != nil {
+		return err
+	}
+	if p.Proxy, err = openSecret(colLLMProxy, p.Proxy); err != nil || into != &p.APIKey {
 		return err
 	}
 	p.APIKey, err = openSecret(colLLMKey, p.APIKey)
@@ -191,12 +194,16 @@ func (d *DB) SaveProfile(p *LLMProfile) (int64, error) {
 	if err != nil {
 		return 0, err
 	}
+	proxy, err := sealSecret(colLLMProxy, p.Proxy)
+	if err != nil {
+		return 0, err
+	}
 	r := p.Retry.Clamped()
 	if p.ID == 0 {
 		var id int64
 		err := d.QueryRow(`INSERT INTO llm_profiles(name,format,base_url,proxy,model,api_key,api_key_hint,rate_per_second,rate_per_minute,context_window_k,reasoning_effort,priority,pool_exclude,thinking_type,streaming,max_tokens,max_tokens_field,session_header_key,retry_connect_attempts,retry_connect_interval_ms,retry_empty_attempts,retry_empty_interval_ms,retry_stream_attempts,retry_stream_interval_ms,user_agent)
 VALUES ($1,$2,NULLIF($3,''),NULLIF($4,''),$5,NULLIF($6,''),NULLIF($7,''),$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21,$22,$23,$24,$25) RETURNING id`,
-			p.Name, p.Format, p.BaseURL, p.Proxy, p.Model, key, hint, p.RatePerSecond, p.RatePerMinute, p.ContextWindowK, p.ReasoningEffort, p.Priority, p.PoolExclude, p.ThinkingType, p.Streaming, p.MaxTokens, p.MaxTokensField, p.SessionHeaderKey,
+			p.Name, p.Format, p.BaseURL, proxy, p.Model, key, hint, p.RatePerSecond, p.RatePerMinute, p.ContextWindowK, p.ReasoningEffort, p.Priority, p.PoolExclude, p.ThinkingType, p.Streaming, p.MaxTokens, p.MaxTokensField, p.SessionHeaderKey,
 			r.Connect.Attempts, r.Connect.IntervalMS, r.Empty.Attempts, r.Empty.IntervalMS, r.Stream.Attempts, r.Stream.IntervalMS, p.UserAgent).Scan(&id)
 		if err == nil {
 			_, err = d.saveProfilePrices(id, p)
@@ -205,7 +212,7 @@ VALUES ($1,$2,NULLIF($3,''),NULLIF($4,''),$5,NULLIF($6,''),NULLIF($7,''),$8,$9,$
 	}
 	if p.APIKey == "" {
 		_, err := d.Exec(`UPDATE llm_profiles SET name=$1,format=$2,base_url=NULLIF($3,''),proxy=NULLIF($4,''),model=$5,rate_per_second=$6,rate_per_minute=$7,context_window_k=$8,reasoning_effort=$9,priority=$10,pool_exclude=$11,thinking_type=$12,streaming=$13,max_tokens=$14,max_tokens_field=$15,session_header_key=$16,retry_connect_attempts=$17,retry_connect_interval_ms=$18,retry_empty_attempts=$19,retry_empty_interval_ms=$20,retry_stream_attempts=$21,retry_stream_interval_ms=$22,user_agent=$23 WHERE id=$24`,
-			p.Name, p.Format, p.BaseURL, p.Proxy, p.Model, p.RatePerSecond, p.RatePerMinute, p.ContextWindowK, p.ReasoningEffort, p.Priority, p.PoolExclude, p.ThinkingType, p.Streaming, p.MaxTokens, p.MaxTokensField, p.SessionHeaderKey,
+			p.Name, p.Format, p.BaseURL, proxy, p.Model, p.RatePerSecond, p.RatePerMinute, p.ContextWindowK, p.ReasoningEffort, p.Priority, p.PoolExclude, p.ThinkingType, p.Streaming, p.MaxTokens, p.MaxTokensField, p.SessionHeaderKey,
 			r.Connect.Attempts, r.Connect.IntervalMS, r.Empty.Attempts, r.Empty.IntervalMS, r.Stream.Attempts, r.Stream.IntervalMS, p.UserAgent, p.ID)
 		if err == nil {
 			_, err = d.saveProfilePrices(p.ID, p)
@@ -213,7 +220,7 @@ VALUES ($1,$2,NULLIF($3,''),NULLIF($4,''),$5,NULLIF($6,''),NULLIF($7,''),$8,$9,$
 		return p.ID, err
 	}
 	_, err = d.Exec(`UPDATE llm_profiles SET name=$1,format=$2,base_url=NULLIF($3,''),proxy=NULLIF($4,''),model=$5,api_key=$6,api_key_hint=$7,rate_per_second=$8,rate_per_minute=$9,context_window_k=$10,reasoning_effort=$11,priority=$12,pool_exclude=$13,thinking_type=$14,streaming=$15,max_tokens=$16,max_tokens_field=$17,session_header_key=$18,retry_connect_attempts=$19,retry_connect_interval_ms=$20,retry_empty_attempts=$21,retry_empty_interval_ms=$22,retry_stream_attempts=$23,retry_stream_interval_ms=$24,user_agent=$25 WHERE id=$26`,
-		p.Name, p.Format, p.BaseURL, p.Proxy, p.Model, key, hint, p.RatePerSecond, p.RatePerMinute, p.ContextWindowK, p.ReasoningEffort, p.Priority, p.PoolExclude, p.ThinkingType, p.Streaming, p.MaxTokens, p.MaxTokensField, p.SessionHeaderKey,
+		p.Name, p.Format, p.BaseURL, proxy, p.Model, key, hint, p.RatePerSecond, p.RatePerMinute, p.ContextWindowK, p.ReasoningEffort, p.Priority, p.PoolExclude, p.ThinkingType, p.Streaming, p.MaxTokens, p.MaxTokensField, p.SessionHeaderKey,
 		r.Connect.Attempts, r.Connect.IntervalMS, r.Empty.Attempts, r.Empty.IntervalMS, r.Stream.Attempts, r.Stream.IntervalMS, p.UserAgent, p.ID)
 	if err == nil {
 		_, err = d.saveProfilePrices(p.ID, p)

db/secrets.go

@@ -19,7 +19,8 @@ import (
 	"sync/atomic"
 )
 
-// Secrets at rest: AES-256-GCM, a random nonce per value, AAD "<table>.<column>".
+// Secrets at rest: AES-256-GCM, a random nonce per value, AAD "<table>.<column>"
+// ("settings.<key>" for the secret settings).
 // TEXT stores "enc:v1:<base64(nonce||ciphertext)>"; JSONB stores
 // {"__artex_enc":"enc:v1:..."} over the canonical JSON. Empty values stay empty.
 // A value that fails to decrypt is an error, never returned as-is.
@@ -34,9 +35,36 @@ const (
 type secretColumn struct {
 	table, col string
 	json       bool
+	setting    string // a settings row: its key; "" for a table column
 }
 
-func (c secretColumn) aad() string { return c.table + "." + c.col }
+func (c secretColumn) aad() string {
+	if c.setting != "" {
+		return "settings." + c.setting
+	}
+	return c.table + "." + c.col
+}
+
+// rowFilter limits a settings entry to its own row; the key is a code-owned
+// constant from secretSettingKeys, never input. tools.exec covers the
+// user-created tools only: the seeds rewrite the built-in rows in clear.
+func (c secretColumn) rowFilter() string {
+	if c.setting != "" {
+		return ` AND key='` + c.setting + `'`
+	}
+	if c == colToolExec {
+		return ` AND system=false`
+	}
+	return ""
+}
+
+// idCol names the row key: settings and tools rows are keyed by name, the rest by id.
+func (c secretColumn) idCol() string {
+	if c.setting != "" || c == colToolExec {
+		return "key"
+	}
+	return "id"
+}
 
 // valueExpr is the SQL text that holds the ciphertext, if any.
 func (c secretColumn) valueExpr() string {
@@ -47,13 +75,38 @@ func (c secretColumn) valueExpr() string {
 }
 
 var (
-	colLLMKey      = secretColumn{"llm_profiles", "api_key", false}
-	colMCPEnv      = secretColumn{"mcp_servers", "env", true}
-	colCredPass    = secretColumn{"task_credentials", "password", false}
-	colNotifConfig = secretColumn{"notification_channels", "config", true}
-	secretColumns  = []secretColumn{colLLMKey, colMCPEnv, colCredPass, colNotifConfig}
+	colLLMKey      = secretColumn{"llm_profiles", "api_key", false, ""}
+	colLLMProxy    = secretColumn{"llm_profiles", "proxy", false, ""} // may carry user:pass
+	colMCPEnv      = secretColumn{"mcp_servers", "env", true, ""}
+	colCredPass    = secretColumn{"task_credentials", "password", false, ""}
+	colNotifConfig = secretColumn{"notification_channels", "config", true, ""}
+	colToolExec    = secretColumn{"tools", "exec", true, ""} // system=false rows: headers, proxy, body, code, command
+	secretColumns  = append([]secretColumn{colLLMKey, colLLMProxy, colMCPEnv, colCredPass, colNotifConfig, colToolExec}, secretSettingColumns()...)
 )
 
+// secretSettingKeys are the settings stored encrypted, AAD "settings.<key>".
+// Every other setting stays in clear.
+var secretSettingKeys = []string{"brave_search_api_key", "tavily_search_api_key", "web_search_proxy", "global_proxy"}
+
+func secretSettingColumns() []secretColumn {
+	out := make([]secretColumn, 0, len(secretSettingKeys))
+	for _, k := range secretSettingKeys {
+		out = append(out, secretColumn{"settings", "value", false, k})
+	}
+	return out
+}
+
+// secretSetting returns the secret column of a settings key, ok=false when the
+// key is stored in clear.
+func secretSetting(key string) (secretColumn, bool) {
+	for _, c := range secretColumns {
+		if c.setting != "" && c.setting == key {
+			return c, true
+		}
+	}
+	return secretColumn{}, false
+}
+
 type secretBox struct{ aead cipher.AEAD }
 
 var activeSecretBox atomic.Pointer[secretBox]
@@ -203,7 +256,7 @@ func (d *DB) InitSecrets(keyDir string) error {
 		// A key other than the one that sealed the data fails here, at startup.
 		for _, c := range secretColumns {
 			var v string
-			err := conn.QueryRowContext(ctx, `SELECT `+c.valueExpr()+` FROM `+c.table+` WHERE `+c.valueExpr()+` LIKE 'enc:v1:%' LIMIT 1`).Scan(&v)
+			err := conn.QueryRowContext(ctx, `SELECT `+c.valueExpr()+` FROM `+c.table+` WHERE `+c.valueExpr()+` LIKE 'enc:v1:%'`+c.rowFilter()+` LIMIT 1`).Scan(&v)
 			if err == nil {
 				_, err = box.decrypt(c.aad(), v)
 			}
@@ -241,7 +294,7 @@ func loadSecretKey(ctx context.Context, conn *sql.Conn, keyDir string) ([]byte,
 	}
 	var parts []string
 	for _, c := range secretColumns {
-		parts = append(parts, `(SELECT count(*) FROM `+c.table+` WHERE `+c.valueExpr()+` LIKE 'enc:v1:%')`)
+		parts = append(parts, `(SELECT count(*) FROM `+c.table+` WHERE `+c.valueExpr()+` LIKE 'enc:v1:%'`+c.rowFilter()+`)`)
 	}
 	var n int64
 	if err := conn.QueryRowContext(ctx, `SELECT `+strings.Join(parts, "+")).Scan(&n); err != nil {
@@ -279,14 +332,14 @@ func loadSecretKey(ctx context.Context, conn *sql.Conn, keyDir string) ([]byte,
 func backfillSecrets(ctx context.Context, conn *sql.Conn, box *secretBox) (int, error) {
 	total := 0
 	for _, c := range secretColumns {
-		var ids []int64
+		var ids []any // int64 ids, or the settings key
 		var olds, news []string
-		rows, err := conn.QueryContext(ctx, `SELECT id, `+c.col+`::text FROM `+c.table+` WHERE `+c.col+` IS NOT NULL`)
+		rows, err := conn.QueryContext(ctx, `SELECT `+c.idCol()+`, `+c.col+`::text FROM `+c.table+` WHERE `+c.col+` IS NOT NULL`+c.rowFilter())
 		if err != nil {
 			return total, err
 		}
 		for rows.Next() {
-			var id int64
+			var id any
 			var old string
 			if err = rows.Scan(&id, &old); err != nil {
 				break
@@ -296,7 +349,7 @@ func backfillSecrets(ctx context.Context, conn *sql.Conn, box *secretBox) (int,
 			}
 			nv, serr := box.seal(c, old)
 			if serr != nil {
-				err = fmt.Errorf("backfill %s id=%d: %w", c.aad(), id, serr)
+				err = fmt.Errorf("backfill %s id=%v: %w", c.aad(), id, serr)
 				break
 			}
 			if isSealed(c, nv) { // empty values stay as they are
@@ -315,9 +368,9 @@ func backfillSecrets(ctx context.Context, conn *sql.Conn, box *secretBox) (int,
 			cast = "::jsonb"
 		}
 		for i, id := range ids {
-			res, err := conn.ExecContext(ctx, `UPDATE `+c.table+` SET `+c.col+`=$1`+cast+` WHERE id=$2 AND `+c.col+`::text=$3`, news[i], id, olds[i])
+			res, err := conn.ExecContext(ctx, `UPDATE `+c.table+` SET `+c.col+`=$1`+cast+` WHERE `+c.idCol()+`=$2 AND `+c.col+`::text=$3`, news[i], id, olds[i])
 			if err != nil {
-				return total, fmt.Errorf("backfill %s id=%d: %w", c.aad(), id, err)
+				return total, fmt.Errorf("backfill %s id=%v: %w", c.aad(), id, err)
 			}
 			if n, _ := res.RowsAffected(); n > 0 {
 				total++

db/secrets_test.go

@@ -5,6 +5,7 @@ import (
 	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -54,7 +55,20 @@ func TestSecretBoxCrypto(t *testing.T) {
 
 type secretRows struct{ llm, mcp, cred, ch, task int64 }
 
-var plainSecrets = []string{"sk-plain-llm", "mcp-plain-tok", "plain-pass", "hook-plain-secret"}
+var plainSecrets = []string{"sk-plain-llm", "mcp-plain-tok", "plain-pass", "hook-plain-secret", "llmproxy-plain-pass",
+	"brave-plain", "tavily-plain", "wsproxy-plain-pass", "gproxy-plain-pass"}
+
+// secretSettingValues are the four secret settings written by the fixture.
+var secretSettingValues = map[string]string{
+	"brave_search_api_key":  "brave-plain",
+	"tavily_search_api_key": "tavily-plain",
+	"web_search_proxy":      "socks5://u:wsproxy-plain-pass@ws.example:1080",
+	"global_proxy":          "http://u:gproxy-plain-pass@gp.example:3128",
+}
+
+const llmProxyPlain = "http://u:llmproxy-plain-pass@llm-proxy.example:3128"
+
+const deleteSecretSettings = `DELETE FROM settings WHERE key IN ('brave_search_api_key','tavily_search_api_key','web_search_proxy','global_proxy')`
 
 // secretFixture writes one secret to each location, through the db API or, for
 // a legacy database, as raw plaintext SQL.
@@ -70,6 +84,7 @@ func secretFixture(t *testing.T, d *DB, legacy bool) (r secretRows) {
 		d.Exec(`DELETE FROM llm_profiles WHERE id=$1`, r.llm)
 		d.Exec(`DELETE FROM mcp_servers WHERE id=$1`, r.mcp)
 		d.Exec(`DELETE FROM notification_channels WHERE id=$1`, r.ch)
+		d.Exec(deleteSecretSettings)
 	})
 	env, cfg := `{"Authorization":"mcp-plain-tok"}`, `{"url":"https://h.example","headers":{"X":"hook-plain-secret"}}`
 	if legacy {
@@ -78,13 +93,23 @@ func secretFixture(t *testing.T, d *DB, legacy bool) (r secretRows) {
 				t.Fatal(err)
 			}
 		}
-		ins(&r.llm, `INSERT INTO llm_profiles(name,format,model,api_key) VALUES ('t-sec','openai','m','sk-plain-llm') RETURNING id`)
+		ins(&r.llm, `INSERT INTO llm_profiles(name,format,model,api_key,proxy) VALUES ('t-sec','openai','m','sk-plain-llm',$1) RETURNING id`, llmProxyPlain)
+		for k, v := range secretSettingValues {
+			if _, err := d.Exec(`INSERT INTO settings(key,value) VALUES ($1,$2)`, k, v); err != nil {
+				t.Fatal(err)
+			}
+		}
 		ins(&r.mcp, `INSERT INTO mcp_servers(name,transport,env) VALUES ('t-sec','http',$1) RETURNING id`, env)
 		ins(&r.cred, `INSERT INTO task_credentials(task_id,domain,username,password) VALUES ($1,'x.example','u','plain-pass') RETURNING id`, r.task)
 		ins(&r.ch, `INSERT INTO notification_channels(name,kind,config) VALUES ('t-sec','webhook',$1) RETURNING id`, cfg)
 		return r
 	}
-	r.llm, err = d.SaveProfile(&LLMProfile{Name: "t-sec", Format: "openai", Model: "m", APIKey: "sk-plain-llm"})
+	r.llm, err = d.SaveProfile(&LLMProfile{Name: "t-sec", Format: "openai", Model: "m", APIKey: "sk-plain-llm", Proxy: llmProxyPlain})
+	for k, v := range secretSettingValues {
+		if err == nil {
+			err = d.SetSetting(k, v)
+		}
+	}
 	if err == nil {
 		r.mcp, err = d.SaveMCP(&MCPServer{Name: "t-sec", Transport: "http", Env: json.RawMessage(env)})
 	}
@@ -102,19 +127,28 @@ func secretFixture(t *testing.T, d *DB, legacy bool) (r secretRows) {
 	return r
 }
 
-// rawSecrets reads the four columns as stored in PostgreSQL.
+// rawSecrets reads the secret columns and settings as stored in PostgreSQL.
 func rawSecrets(t *testing.T, d *DB, r secretRows) string {
 	t.Helper()
-	var a, b, c, e string
+	var a, b, c, e, px string
 	if err := d.QueryRow(`SELECT (SELECT api_key FROM llm_profiles WHERE id=$1), (SELECT env::text FROM mcp_servers WHERE id=$2),
-(SELECT password FROM task_credentials WHERE id=$3), (SELECT config::text FROM notification_channels WHERE id=$4)`,
-		r.llm, r.mcp, r.cred, r.ch).Scan(&a, &b, &c, &e); err != nil {
+(SELECT password FROM task_credentials WHERE id=$3), (SELECT config::text FROM notification_channels WHERE id=$4),
+(SELECT proxy FROM llm_profiles WHERE id=$1)`,
+		r.llm, r.mcp, r.cred, r.ch).Scan(&a, &b, &c, &e, &px); err != nil {
 		t.Fatal(err)
 	}
-	if !isEncrypted(a) || !isSealed(colMCPEnv, b) || !isEncrypted(c) || !isSealed(colNotifConfig, e) {
+	if !isEncrypted(a) || !isSealed(colMCPEnv, b) || !isEncrypted(c) || !isSealed(colNotifConfig, e) || !isEncrypted(px) {
 		t.Fatal("a stored secret is not encrypted")
 	}
-	all := strings.Join([]string{a, b, c, e}, "|")
+	vals := []string{a, b, c, e, px}
+	for _, k := range secretSettingKeys {
+		var v string
+		if err := d.QueryRow(`SELECT value FROM settings WHERE key=$1`, k).Scan(&v); err != nil || !isEncrypted(v) {
+			t.Fatalf("setting %s not encrypted at rest (%v)", k, err)
+		}
+		vals = append(vals, v)
+	}
+	all := strings.Join(vals, "|")
 	for _, p := range plainSecrets {
 		if strings.Contains(all, p) {
 			t.Fatalf("plaintext %q found at rest", p)
@@ -128,7 +162,20 @@ func assertPlainReads(t *testing.T, d *DB, r secretRows) {
 	t.Helper()
 	got := ""
 	if p, err := d.ProfileByID(r.llm); err == nil && p != nil {
-		got += p.APIKey
+		got += p.APIKey + p.Proxy
+	}
+	if ps, err := d.ListProfiles(); err == nil {
+		for _, p := range ps {
+			if p.ID == r.llm && p.Proxy != llmProxyPlain {
+				t.Fatalf("ListProfiles proxy %q not decrypted", p.Proxy)
+			}
+		}
+	}
+	for k, want := range secretSettingValues {
+		if v, ok, err := d.GetSetting(k); err != nil || !ok || v != want {
+			t.Fatalf("GetSetting(%s) = %q %v %v", k, v, ok, err)
+		}
+		got += want
 	}
 	ms, _ := d.ListMCP()
 	for _, m := range ms {
@@ -194,4 +241,87 @@ func TestSecretsBackfillLegacyAndKeyChecks(t *testing.T) {
 		t.Fatalf("want wrong-key refusal, got %v", err)
 	}
 	assertPlainReads(t, d, r) // the active key is unchanged
+
+	// The no-key refusal counts the four encrypted settings.
+	t.Setenv(secretKeyEnv, "")
+	withSettings := encryptedCount(t, d, dir)
+	if _, err := d.Exec(deleteSecretSettings); err != nil {
+		t.Fatal(err)
+	}
+	if n := encryptedCount(t, d, dir); withSettings-n != len(secretSettingKeys) {
+		t.Fatalf("no-key refusal counted %d then %d encrypted values; the settings must count", withSettings, n)
+	}
+
+	// A setting sealed under another key fails the startup key check.
+	other, _ := newSecretBox([]byte("ffffffffffffffffffffffffffffffff"))
+	v, _ := other.encrypt("settings.global_proxy", "http://other.example:3128")
+	if _, err := d.Exec(`INSERT INTO settings(key,value) VALUES ('global_proxy',$1)`, v); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv(secretKeyEnv, base64.StdEncoding.EncodeToString(testSecretKey))
+	if err := d.InitSecrets(t.TempDir()); err == nil || !strings.Contains(err.Error(), "settings.global_proxy") {
+		t.Fatalf("want a key-check failure on settings.global_proxy, got %v", err)
+	}
+	if _, err := d.Exec(deleteSecretSettings); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// encryptedCount reads the encrypted-value count from the no-key refusal.
+func encryptedCount(t *testing.T, d *DB, dir string) int {
+	t.Helper()
+	err := d.InitSecrets(dir)
+	var n int
+	if err == nil {
+		t.Fatal("want a no-key refusal")
+	}
+	if _, serr := fmt.Sscanf(err.Error(), "the database holds %d encrypted", &n); serr != nil {
+		t.Fatalf("refusal %q: %v", err, serr)
+	}
+	return n
+}
+
+// Secret settings: empty stays empty, InsertSettingIfAbsent encrypts, other
+// settings stay in clear; an empty LLM proxy stays empty.
+func TestSecretSettingsEmptyAndClear(t *testing.T) {
+	d, err := Open(testDSN(t))
+	if err != nil {
+		t.Skipf("postgres unavailable (%v) — skipping", err)
+	}
+	t.Cleanup(func() {
+		d.Exec(deleteSecretSettings)
+		d.Exec(`DELETE FROM settings WHERE key='t_sec_clear'`)
+		d.Exec(`DELETE FROM llm_profiles WHERE name='t-sec-noproxy'`)
+		d.Close()
+	})
+	raw := func(k string) string {
+		var v string
+		if err := d.QueryRow(`SELECT value FROM settings WHERE key=$1`, k).Scan(&v); err != nil {
+			t.Fatal(err)
+		}
+		return v
+	}
+	if err := d.SetSetting("global_proxy", ""); err != nil || raw("global_proxy") != "" {
+		t.Fatalf("empty secret setting must stay empty (%v)", err)
+	}
+	if ok, err := d.InsertSettingIfAbsent("tavily_search_api_key", "tavily-insert"); err != nil || !ok || !isEncrypted(raw("tavily_search_api_key")) {
+		t.Fatalf("InsertSettingIfAbsent must encrypt a secret setting (%v %v)", ok, err)
+	}
+	if v, _, err := d.GetSetting("tavily_search_api_key"); err != nil || v != "tavily-insert" {
+		t.Fatalf("read back %q %v", v, err)
+	}
+	if err := d.SetSetting("t_sec_clear", "visible"); err != nil || raw("t_sec_clear") != "visible" {
+		t.Fatalf("a non-secret setting must stay in clear (%v)", err)
+	}
+	id, err := d.SaveProfile(&LLMProfile{Name: "t-sec-noproxy", Format: "openai", Model: "m", APIKey: "k"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	var px *string
+	if err := d.QueryRow(`SELECT proxy FROM llm_profiles WHERE id=$1`, id).Scan(&px); err != nil || px != nil {
+		t.Fatalf("empty proxy stored as %v (%v), want NULL", px, err)
+	}
+	if p, err := d.ProfileByID(id); err != nil || p.Proxy != "" {
+		t.Fatalf("empty proxy read back as %q (%v)", p.Proxy, err)
+	}
 }

db/settings.go

@@ -5,7 +5,8 @@ import "database/sql"
 // Settings is a tiny key-value store for global app config the UI toggles at
 // runtime (e.g. traffic_capture). Missing keys fall back to caller defaults.
 
-// GetSetting returns the stored value and ok=false when the key is unset.
+// GetSetting returns the stored value and ok=false when the key is unset. A
+// secret setting (secretSettingKeys) is decrypted.
 func (d *DB) GetSetting(key string) (value string, ok bool, err error) {
 	err = d.QueryRow(`SELECT value FROM settings WHERE key=$1`, key).Scan(&value)
 	if err == sql.ErrNoRows {
@@ -14,12 +15,29 @@ func (d *DB) GetSetting(key string) (value string, ok bool, err error) {
 	if err != nil {
 		return "", false, err
 	}
+	if c, secret := secretSetting(key); secret {
+		if value, err = openSecret(c, value); err != nil {
+			return "", false, err
+		}
+	}
 	return value, true, nil
 }
 
+// sealSetting encrypts the value of a secret setting; other values pass as is.
+func sealSetting(key, value string) (string, error) {
+	if c, secret := secretSetting(key); secret {
+		return sealSecret(c, value)
+	}
+	return value, nil
+}
+
 // SetSetting upserts a setting value.
 func (d *DB) SetSetting(key, value string) error {
-	_, err := d.Exec(`
+	value, err := sealSetting(key, value)
+	if err != nil {
+		return err
+	}
+	_, err = d.Exec(`
 INSERT INTO settings(key, value) VALUES ($1, $2)
 ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value, updated_at = now()`, key, value)
 	return err
@@ -32,6 +50,9 @@ ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value, updated_at = now()`, key
 // fast-fail path — on a read error or a concurrent race, the existing value will not be
 // silently overwritten by ON CONFLICT DO UPDATE.
 func (d *DB) InsertSettingIfAbsent(key, value string) (inserted bool, err error) {
+	if value, err = sealSetting(key, value); err != nil {
+		return false, err
+	}
 	res, err := d.Exec(`
 INSERT INTO settings(key, value) VALUES ($1, $2)
 ON CONFLICT (key) DO NOTHING`, key, value)

db/tools.go

@@ -110,6 +110,13 @@ func scanTool(rows interface{ Scan(...any) error }) (*Tool, error) {
 	if err := rows.Scan(&t.Key, &t.System, &t.Description, &t.Schema, &agents, &t.Enabled, &t.Kind, &t.Exec, &t.Deferred); err != nil {
 		return nil, err
 	}
+	if !t.System { // a custom tool's exec is sealed at rest
+		plain, err := openSecret(colToolExec, string(t.Exec))
+		if err != nil {
+			return nil, err
+		}
+		t.Exec = json.RawMessage(plain)
+	}
 	if len(agents) > 0 {
 		_ = json.Unmarshal(agents, &t.Agents)
 	}
@@ -154,15 +161,15 @@ func (d *DB) CreateCustomTool(t *Tool) error {
 	if len(schema) == 0 {
 		schema = json.RawMessage("{}")
 	}
-	exec := t.Exec
-	if len(exec) == 0 {
-		exec = json.RawMessage("{}")
+	exec, err := sealToolExec(t.Exec)
+	if err != nil {
+		return err
 	}
 	agents, _ := json.Marshal(t.Agents)
 	if len(agents) == 0 {
 		agents = json.RawMessage("[]")
 	}
-	_, err := d.Exec(`
+	_, err = d.Exec(`
 INSERT INTO tools(key, system, description, schema, agents, enabled, kind, exec, deferred)
 VALUES ($1, false, $2, $3, $4, $5, $6, $7, $8)`,
 		t.Key, t.Description, schema, agents, t.Enabled, t.Kind, exec, t.Deferred)
@@ -176,21 +183,29 @@ func (d *DB) UpdateCustomTool(t *Tool) error {
 	if len(schema) == 0 {
 		schema = json.RawMessage("{}")
 	}
-	exec := t.Exec
-	if len(exec) == 0 {
-		exec = json.RawMessage("{}")
+	exec, err := sealToolExec(t.Exec)
+	if err != nil {
+		return err
 	}
 	agents, _ := json.Marshal(t.Agents)
 	if len(agents) == 0 {
 		agents = json.RawMessage("[]")
 	}
-	_, err := d.Exec(`
+	_, err = d.Exec(`
 UPDATE tools SET description=$2, schema=$3, agents=$4, enabled=$5, kind=$6, exec=$7, deferred=$8
 WHERE key=$1 AND system=false`,
 		t.Key, t.Description, schema, agents, t.Enabled, t.Kind, exec, t.Deferred)
 	return err
 }
 
+// sealToolExec encrypts a custom tool's exec spec for storage; empty means {}.
+func sealToolExec(exec json.RawMessage) (string, error) {
+	if len(exec) == 0 {
+		exec = json.RawMessage("{}")
+	}
+	return sealSecret(colToolExec, string(exec))
+}
+
 // DeleteCustomTool removes a custom tool (system=false only; built-ins protected).
 func (d *DB) DeleteCustomTool(key string) error {
 	_, err := d.Exec(`DELETE FROM tools WHERE key=$1 AND system=false`, key)

db/tools_secrets_test.go

@@ -0,0 +1,184 @@
+package db
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+// toolExecPlain is a custom http tool's exec carrying a secret in every field
+// the phase 3 encryption covers.
+const toolExecPlain = `{"method":"GET","url":"https://api.example/x","headers":{"Authorization":"Bearer tool-hdr-plain"},` +
+	`"body":"tool-body-plain","proxy":"http://u:tool-proxy-plain@p.example:3128"}`
+
+var toolPlainSecrets = []string{"tool-hdr-plain", "tool-body-plain", "tool-proxy-plain", "tool-cmd-plain"}
+
+func rawToolExec(t *testing.T, d *DB, key string) string {
+	t.Helper()
+	var v string
+	if err := d.QueryRow(`SELECT exec::text FROM tools WHERE key=$1`, key).Scan(&v); err != nil {
+		t.Fatal(err)
+	}
+	return v
+}
+
+// assertToolExecSealed checks a custom tool's exec is sealed at rest and read
+// back in clear, equal to want, by every db getter.
+func assertToolExecSealed(t *testing.T, d *DB, key, want string) {
+	t.Helper()
+	raw := rawToolExec(t, d, key)
+	if !isSealed(colToolExec, raw) {
+		t.Fatalf("tools.exec of %s not sealed at rest: %s", key, raw)
+	}
+	for _, p := range toolPlainSecrets {
+		if strings.Contains(raw, p) {
+			t.Fatalf("plaintext %q found at rest", p)
+		}
+	}
+	var got []json.RawMessage
+	if tl, err := d.GetTool(key); err != nil || tl == nil {
+		t.Fatalf("GetTool: %v", err)
+	} else {
+		got = append(got, tl.Exec)
+	}
+	for _, list := range []func() ([]*Tool, error){d.ListTools, d.ListCustomTools} {
+		ts, err := list()
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, tl := range ts {
+			if tl.Key == key {
+				got = append(got, tl.Exec)
+			}
+		}
+	}
+	if len(got) != 3 {
+		t.Fatalf("tool %s read by %d getters, want 3", key, len(got))
+	}
+	for _, g := range got {
+		if !jsonEqual(t, string(g), want) {
+			t.Fatalf("exec read back as %s, want %s", g, want)
+		}
+	}
+}
+
+func jsonEqual(t *testing.T, a, b string) bool {
+	t.Helper()
+	var x, y any
+	if json.Unmarshal([]byte(a), &x) != nil || json.Unmarshal([]byte(b), &y) != nil {
+		return false
+	}
+	ca, _ := json.Marshal(x)
+	cb, _ := json.Marshal(y)
+	return string(ca) == string(cb)
+}
+
+func TestToolExecSealedAtRest(t *testing.T) {
+	d, err := Open(testDSN(t))
+	if err != nil {
+		t.Skipf("postgres unavailable (%v) — skipping", err)
+	}
+	t.Cleanup(func() {
+		d.Exec(`DELETE FROM tools WHERE key LIKE 't_secexec%'`)
+		d.Close()
+	})
+	if err := d.CreateCustomTool(&Tool{Key: "t_secexec", Kind: "http", Exec: json.RawMessage(toolExecPlain), Enabled: true}); err != nil {
+		t.Fatal(err)
+	}
+	assertToolExecSealed(t, d, "t_secexec", toolExecPlain)
+	first := rawToolExec(t, d, "t_secexec")
+
+	cmd := `{"command":"curl -H 'X-Key: tool-cmd-plain' {args}","timeout_ms":5000}`
+	if err := d.UpdateCustomTool(&Tool{Key: "t_secexec", Kind: "command", Exec: json.RawMessage(cmd), Enabled: true}); err != nil {
+		t.Fatal(err)
+	}
+	assertToolExecSealed(t, d, "t_secexec", cmd)
+	if err := d.UpdateCustomTool(&Tool{Key: "t_secexec", Kind: "http", Exec: json.RawMessage(toolExecPlain), Enabled: true}); err != nil {
+		t.Fatal(err)
+	}
+	if rawToolExec(t, d, "t_secexec") == first {
+		t.Fatal("the same exec must seal under a fresh nonce")
+	}
+
+	// A shell tool has no exec: {} stays {}.
+	if err := d.CreateCustomTool(&Tool{Key: "t_secexec_shell", Kind: "shell", Enabled: true}); err != nil {
+		t.Fatal(err)
+	}
+	if raw := rawToolExec(t, d, "t_secexec_shell"); raw != "{}" {
+		t.Fatalf("empty exec stored as %s, want {}", raw)
+	}
+	if err := d.CreateCustomTool(&Tool{Key: "t_secexec_resv", Kind: "command", Exec: json.RawMessage(`{"__artex_enc":"x"}`)}); err == nil {
+		t.Fatal("reserved key must be refused on write")
+	}
+
+	// A value sealed under another key fails the read (fail closed).
+	other, _ := newSecretBox([]byte("ffffffffffffffffffffffffffffffff"))
+	foreign, _ := other.seal(colToolExec, toolExecPlain)
+	if _, err := d.Exec(`UPDATE tools SET exec=$1::jsonb WHERE key='t_secexec'`, foreign); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := d.GetTool("t_secexec"); err == nil || !strings.Contains(err.Error(), "tools.exec") {
+		t.Fatalf("a foreign ciphertext must fail the read, got %v", err)
+	}
+	if _, err := d.ListCustomTools(); err == nil {
+		t.Fatal("ListCustomTools must fail on a foreign ciphertext")
+	}
+}
+
+func TestToolExecBackfillAndKeyChecks(t *testing.T) {
+	d, err := Open(testDSN(t))
+	if err != nil {
+		t.Skipf("postgres unavailable (%v) — skipping", err)
+	}
+	t.Cleanup(func() {
+		d.Exec(`DELETE FROM tools WHERE key LIKE 't_secexec%'`)
+		d.Close()
+	})
+	sysExec := `{"command":"echo system-plain"}`
+	for _, q := range []struct {
+		key, exec string
+		system    bool
+	}{{"t_secexec_legacy", toolExecPlain, false}, {"t_secexec_sys", sysExec, true}, {"t_secexec_empty", `{}`, false}} {
+		if _, err := d.Exec(`INSERT INTO tools(key, system, kind, exec) VALUES ($1, $2, 'http', $3::jsonb)`, q.key, q.system, q.exec); err != nil {
+			t.Fatal(err)
+		}
+	}
+	t.Setenv(secretKeyEnv, base64.StdEncoding.EncodeToString(testSecretKey))
+	if err := d.InitSecrets(t.TempDir()); err != nil {
+		t.Fatal(err)
+	}
+	assertToolExecSealed(t, d, "t_secexec_legacy", toolExecPlain)
+	first := rawToolExec(t, d, "t_secexec_legacy")
+	if raw := rawToolExec(t, d, "t_secexec_sys"); !jsonEqual(t, raw, sysExec) {
+		t.Fatalf("a system tool's exec must stay in clear, got %s", raw)
+	}
+	if raw := rawToolExec(t, d, "t_secexec_empty"); raw != "{}" {
+		t.Fatalf("an empty exec must stay {}, got %s", raw)
+	}
+	if err := d.InitSecrets(t.TempDir()); err != nil || rawToolExec(t, d, "t_secexec_legacy") != first {
+		t.Fatalf("second backfill must leave the ciphertext untouched (%v)", err)
+	}
+
+	// Missing key: the sealed exec counts in the refusal.
+	t.Setenv(secretKeyEnv, "")
+	dir := t.TempDir()
+	withTool := encryptedCount(t, d, dir)
+	if _, err := d.Exec(`UPDATE tools SET exec='{}'::jsonb WHERE key='t_secexec_legacy'`); err != nil {
+		t.Fatal(err)
+	}
+	if n := encryptedCount(t, d, dir); withTool-n != 1 {
+		t.Fatalf("no-key refusal counted %d then %d encrypted values; tools.exec must count", withTool, n)
+	}
+
+	// Wrong key: an exec sealed under another key fails the startup key check.
+	other, _ := newSecretBox([]byte("ffffffffffffffffffffffffffffffff"))
+	foreign, _ := other.seal(colToolExec, toolExecPlain)
+	if _, err := d.Exec(`UPDATE tools SET exec=$1::jsonb WHERE key='t_secexec_legacy'`, foreign); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv(secretKeyEnv, base64.StdEncoding.EncodeToString(testSecretKey))
+	if err := d.InitSecrets(t.TempDir()); err == nil || !strings.Contains(err.Error(), "tools.exec") {
+		t.Fatalf("want a key-check failure on tools.exec, got %v", err)
+	}
+}

server/customtool.go

@@ -21,6 +21,7 @@ import (
 	"github.com/Autumn-27/artex/egress"
 	"github.com/Autumn-27/artex/guard"
 	"github.com/Autumn-27/artex/intercept"
+	"github.com/Autumn-27/artex/notify"
 	"github.com/Autumn-27/norma/permission"
 	actool "github.com/Autumn-27/norma/tool"
 )
@@ -72,6 +73,11 @@ func (s *Server) pgCreateCustomTool(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 409, "this key already exists (built-in or custom tool)")
 		return
 	}
+	var err error
+	if req.Exec, err = unmaskToolExec("", nil, req.Kind, req.Exec); err != nil { // nothing stored: a placeholder is refused
+		writeErr(w, 400, err.Error())
+		return
+	}
 	if err := pg.CreateCustomTool(&db.Tool{
 		Key: req.Key, Description: req.Description, Schema: req.Schema, Agents: req.Agents,
 		Enabled: req.Enabled, Kind: req.Kind, Exec: req.Exec, Deferred: req.Deferred,
@@ -110,6 +116,10 @@ func (s *Server) pgUpdateCustomTool(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 400, "http tools must provide a parameter JSON Schema (cannot be left empty)")
 		return
 	}
+	if req.Exec, err = unmaskToolExec(existing.Kind, existing.Exec, req.Kind, req.Exec); err != nil {
+		writeErr(w, 400, err.Error())
+		return
+	}
 	if err := pg.UpdateCustomTool(&db.Tool{
 		Key: key, Description: req.Description, Schema: req.Schema, Agents: req.Agents,
 		Enabled: req.Enabled, Kind: req.Kind, Exec: req.Exec, Deferred: req.Deferred,
@@ -138,6 +148,7 @@ func (s *Server) pgDeleteCustomTool(w http.ResponseWriter, r *http.Request) {
 // real tool call — it runs arbitrary command/script/http on the server, which the
 // custom-tool feature already allows, so no new capability is granted.
 type testToolReq struct {
+	Key    string          `json:"key"`  // the saved tool being edited, if any: its stored values replace placeholders
 	Kind   string          `json:"kind"` // command | script | http
 	Exec   json.RawMessage `json:"exec"`
 	Params map[string]any  `json:"params"`
@@ -156,6 +167,23 @@ func (s *Server) pgTestCustomTool(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 400, "invalid request body")
 		return
 	}
+	var storedKind string
+	var stored json.RawMessage
+	if req.Key != "" {
+		t, err := pg.GetTool(req.Key)
+		if err != nil {
+			writeErr(w, 500, err.Error())
+			return
+		}
+		if t != nil && !t.System {
+			storedKind, stored = t.Kind, t.Exec
+		}
+	}
+	var err error
+	if req.Exec, err = unmaskToolExec(storedKind, stored, req.Kind, req.Exec); err != nil {
+		writeErr(w, 400, err.Error())
+		return
+	}
 	params := req.Params
 	if params == nil {
 		params = map[string]any{}
@@ -236,6 +264,86 @@ type httpExec struct {
 	UseRecordingProxy bool              `json:"use_recording_proxy"`
 }
 
+// toolExecFlags are the response-only *_set flags of maskToolExec; never stored.
+var toolExecFlags = []string{"headers_set", "proxy_set", "body_set"}
+
+// maskToolExec is what the API shows of a custom tool's exec: every header value,
+// the proxy and the body become the placeholder, each with a *_set flag.
+func maskToolExec(raw json.RawMessage) json.RawMessage {
+	var e map[string]any
+	if json.Unmarshal(raw, &e) != nil || e == nil {
+		return raw
+	}
+	if h, ok := e["headers"].(map[string]any); ok {
+		set := false
+		for k, v := range h {
+			if v != "" {
+				h[k], set = notify.MaskedPrefix, true
+			}
+		}
+		e["headers_set"] = set
+	}
+	for _, k := range []string{"proxy", "body"} {
+		if s, ok := e[k].(string); ok {
+			e[k], e[k+"_set"] = maskedSecret(s), s != ""
+		}
+	}
+	out, _ := json.Marshal(e)
+	return out
+}
+
+// unmaskToolExec puts the stored value back for every header, proxy or body sent
+// as the placeholder, so a client echoing the list response keeps the stored
+// secret; an explicit value replaces it and "" clears it. A placeholder with
+// nothing stored to keep (stored nil on create) is refused. As for the MCP env,
+// a stored secret is only kept for the destination it was configured for: when
+// the url (exact string) or the kind changes, a placeholder is refused.
+func unmaskToolExec(storedKind string, stored json.RawMessage, kind string, in json.RawMessage) (json.RawMessage, error) {
+	var e, old map[string]any
+	if json.Unmarshal(in, &e) != nil || e == nil {
+		return in, nil // not an object: stored or refused as before
+	}
+	_ = json.Unmarshal(stored, &old)
+	changed, kept := false, false
+	for _, k := range toolExecFlags {
+		if _, ok := e[k]; ok {
+			delete(e, k)
+			changed = true
+		}
+	}
+	oldHeaders, _ := old["headers"].(map[string]any)
+	headers, _ := e["headers"].(map[string]any)
+	for k, v := range headers {
+		if s, ok := v.(string); !ok || !isMaskedSecret(s) {
+			continue
+		}
+		prev, ok := oldHeaders[k]
+		if !ok {
+			return nil, fmt.Errorf("header %q: masked value but nothing stored to keep", k)
+		}
+		headers[k], changed, kept = prev, true, true
+	}
+	for _, k := range []string{"proxy", "body"} {
+		if s, ok := e[k].(string); !ok || !isMaskedSecret(s) {
+			continue
+		}
+		prev, _ := old[k].(string)
+		if prev == "" {
+			return nil, fmt.Errorf("%s: masked value but nothing stored to keep", k)
+		}
+		e[k], changed, kept = prev, true, true
+	}
+	oldURL, _ := old["url"].(string)
+	newURL, _ := e["url"].(string)
+	if kept && (oldURL != newURL || storedKind != kind) {
+		return nil, fmt.Errorf("destination changed (url or kind) while a stored secret was kept: re-enter the masked header/proxy/body or clear it; stored secrets are not sent to a new destination")
+	}
+	if !changed {
+		return in, nil
+	}
+	return json.Marshal(e)
+}
+
 func timeoutOr(ms, def int) time.Duration {
 	if ms <= 0 {
 		return time.Duration(def) * time.Millisecond

server/dto.go

@@ -603,7 +603,8 @@ type LLMProfileDTO struct {
 	Name            string  `json:"name"`
 	Format          string  `json:"format"`
 	BaseURL         string  `json:"base_url,omitempty"`
-	Proxy           string  `json:"proxy,omitempty"`
+	Proxy           string  `json:"proxy,omitempty"` // masked: the placeholder when set
+	ProxySet        bool    `json:"proxy_set"`
 	Model           string  `json:"model"`
 	APIKeyHint      string  `json:"api_key_hint,omitempty"`
 	RatePerSecond   float64 `json:"rate_per_second"`
@@ -641,7 +642,8 @@ func llmProfileDTO(p *db.LLMProfile) LLMProfileDTO {
 		Name:             p.Name,
 		Format:           p.Format,
 		BaseURL:          p.BaseURL,
-		Proxy:            p.Proxy,
+		Proxy:            maskedSecret(p.Proxy),
+		ProxySet:         p.Proxy != "",
 		Model:            p.Model,
 		APIKeyHint:       p.APIKeyHint,
 		RatePerSecond:    p.RatePerSecond,

server/platform_tools.go

@@ -216,6 +216,10 @@ func (s *Server) toolCreateCustomTool() actool.CoreTool {
 			if exist, _ := s.m.pg.GetTool(a.Key); exist != nil {
 				return actool.Errorf("this key already exists: " + a.Key), nil
 			}
+			var err error
+			if a.Exec, err = unmaskToolExec("", nil, a.Kind, a.Exec); err != nil { // nothing stored: a placeholder is refused
+				return actool.Errorf(err.Error()), nil
+			}
 			if err := s.m.pg.CreateCustomTool(toDBTool(a)); err != nil {
 				return actool.Errorf(err.Error()), nil
 			}
@@ -239,6 +243,10 @@ func (s *Server) toolUpdateCustomTool() actool.CoreTool {
 			if a.Kind == "http" && !hasSchemaProps(a.Schema) {
 				return actool.Errorf("http tools must provide a parameter JSON Schema (cannot be empty)"), nil
 			}
+			var err error
+			if a.Exec, err = unmaskToolExec(existing.Kind, existing.Exec, a.Kind, a.Exec); err != nil {
+				return actool.Errorf(err.Error()), nil
+			}
 			if err := s.m.pg.UpdateCustomTool(toDBTool(a)); err != nil {
 				return actool.Errorf(err.Error()), nil
 			}

server/secrets_api_test.go

@@ -144,3 +144,118 @@ func TestMCPMaskedEnvDestinationGuard(t *testing.T) {
 		t.Fatal("explicit env with a new url was not saved")
 	}
 }
+
+// Secret settings and the LLM profile proxy: stored encrypted, never returned
+// in clear; on write the placeholder keeps, an explicit value replaces, ""
+// clears.
+func TestProxySecretsAPI(t *testing.T) {
+	s, _, request := trafficEvidenceServer(t)
+	pg := s.m.PG()
+	t.Cleanup(func() {
+		pg.Exec(`DELETE FROM settings WHERE key IN ('brave_search_api_key','tavily_search_api_key','web_search_proxy','global_proxy')`)
+		pg.Exec(`DELETE FROM llm_profiles WHERE name='t-proxy'`)
+	})
+	secrets := []string{"brave-api-0007", "tavily-api-0008", "wsp-pass-0009", "gp-pass-0010", "llmp-pass-0011"}
+	put := func(body string) {
+		t.Helper()
+		resp := request("PUT", "/api/settings", body)
+		for _, sec := range secrets {
+			if resp.Code != 200 || strings.Contains(resp.Body.String(), sec) {
+				t.Fatalf("PUT /api/settings %s: HTTP %d or a secret returned in clear", body, resp.Code)
+			}
+		}
+	}
+	setting := func(k string) string {
+		t.Helper()
+		var raw string
+		if err := pg.QueryRow(`SELECT value FROM settings WHERE key=$1`, k).Scan(&raw); err != nil {
+			t.Fatal(err)
+		}
+		v, _, err := pg.GetSetting(k)
+		if err != nil || (raw != "" && !strings.HasPrefix(raw, "enc:v1:")) {
+			t.Fatalf("setting %s stored as %q (%v)", k, raw, err)
+		}
+		return v
+	}
+	put(`{"brave_search_api_key":"brave-api-0007","tavily_search_api_key":"tavily-api-0008",
+"web_search_proxy":"socks5://u:wsp-pass-0009@ws.example:1080","global_proxy":"http://u:gp-pass-0010@gp.example:3128"}`)
+	var got map[string]any
+	resp := request("GET", "/api/settings", "")
+	_ = json.Unmarshal(resp.Body.Bytes(), &got)
+	for _, sec := range secrets {
+		if strings.Contains(resp.Body.String(), sec) {
+			t.Fatal("GET /api/settings returned a secret in clear")
+		}
+	}
+	if got["global_proxy"] != "__masked__" || got["global_proxy_set"] != true || got["web_search_proxy"] != "__masked__" || got["web_search_proxy_set"] != true {
+		t.Fatalf("proxies not masked with a presence flag: %v", got)
+	}
+
+	put(`{"web_search_proxy":"__masked__","global_proxy":"__masked__","brave_search_api_key":"__masked__"}`)
+	if setting("web_search_proxy") != "socks5://u:wsp-pass-0009@ws.example:1080" || setting("global_proxy") != "http://u:gp-pass-0010@gp.example:3128" ||
+		setting("brave_search_api_key") != "brave-api-0007" || setting("tavily_search_api_key") != "tavily-api-0008" {
+		t.Fatal("a masked placeholder replaced a stored secret")
+	}
+	put(`{"global_proxy":"http://gp2.example:3128","web_search_proxy":""}`)
+	if setting("global_proxy") != "http://gp2.example:3128" || setting("web_search_proxy") != "" {
+		t.Fatal("explicit value must replace and \"\" must clear")
+	}
+	_ = json.Unmarshal(request("GET", "/api/settings", "").Body.Bytes(), &got)
+	if got["web_search_proxy"] != "" || got["web_search_proxy_set"] != false {
+		t.Fatalf("cleared proxy shown as %v / %v", got["web_search_proxy"], got["web_search_proxy_set"])
+	}
+
+	// LLM profile proxy.
+	id, err := pg.SaveProfile(&db.LLMProfile{Name: "t-proxy", Format: "openai", Model: "m", APIKey: "k", Proxy: "http://u:llmp-pass-0011@llm.example:3128"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	proxy := func() string {
+		var raw *string
+		if err := pg.QueryRow(`SELECT proxy FROM llm_profiles WHERE id=$1`, id).Scan(&raw); err != nil {
+			t.Fatal(err)
+		}
+		if raw != nil && !strings.HasPrefix(*raw, "enc:v1:") {
+			t.Fatalf("profile proxy stored in clear: %q", *raw)
+		}
+		p, err := pg.ProfileByID(id)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return p.Proxy
+	}
+	for _, path := range []string{"/api/llm/profiles", "/api/llm"} {
+		if resp := request("GET", path, ""); resp.Code != 200 || strings.Contains(resp.Body.String(), "llmp-pass-0011") {
+			t.Fatalf("GET %s: HTTP %d or the proxy returned in clear", path, resp.Code)
+		}
+	}
+	var list struct{ Profiles []LLMProfileDTO }
+	_ = json.Unmarshal(request("GET", "/api/llm/profiles", "").Body.Bytes(), &list)
+	for _, p := range list.Profiles {
+		if p.Name == "t-proxy" && (p.Proxy != "__masked__" || !p.ProxySet) {
+			t.Fatalf("profile proxy not masked: %+v", p)
+		}
+	}
+	save := func(proxyJSON string, want int) {
+		t.Helper()
+		body := `{"id":` + strconv.FormatInt(id, 10) + `,"name":"t-proxy","format":"openai","model":"m","proxy":` + proxyJSON + `}`
+		if resp := request("POST", "/api/llm/profiles", body); resp.Code != want {
+			t.Fatalf("save proxy %s: want HTTP %d, got %d %s", proxyJSON, want, resp.Code, resp.Body.String())
+		}
+	}
+	save(`"__masked__"`, 200)
+	if proxy() != "http://u:llmp-pass-0011@llm.example:3128" {
+		t.Fatal("the placeholder replaced the stored profile proxy")
+	}
+	save(`"socks5://llm2.example:1080"`, 200)
+	if proxy() != "socks5://llm2.example:1080" {
+		t.Fatal("explicit proxy not saved")
+	}
+	save(`""`, 200)
+	if proxy() != "" {
+		t.Fatal("empty proxy must clear")
+	}
+	if resp := request("POST", "/api/llm/profiles", `{"name":"t-proxy","format":"openai","model":"m","proxy":"__masked__"}`); resp.Code != 400 {
+		t.Fatalf("a placeholder on a new profile must be refused, got HTTP %d", resp.Code)
+	}
+}

server/server.go

@@ -1355,7 +1355,8 @@ func (s *Server) getLLM(w http.ResponseWriter, r *http.Request) {
 		"provider":         s.llmCfg.Provider(),
 		"model":            s.llmCfg.Model,
 		"base_url":         s.llmCfg.BaseURL,
-		"proxy":            s.llmCfg.Proxy,
+		"proxy":            maskedSecret(s.llmCfg.Proxy),
+		"proxy_set":        s.llmCfg.Proxy != "",
 		"key_set":          s.llmCfg.APIKey != "",
 		"rate_per_second":  s.llmCfg.RatePerSecond,
 		"rate_per_minute":  s.llmCfg.RatePerMinute,
@@ -1383,6 +1384,11 @@ func (s *Server) setLLM(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 400, err.Error())
 		return
 	}
+	if isMaskedSecret(req.Proxy) { // getLLM returns the proxy masked: keep the current one
+		s.cfgMu.Lock()
+		req.Proxy = s.llmCfg.Proxy
+		s.cfgMu.Unlock()
+	}
 	cfg := agent.ConfigFrom(req.Provider, req.Model, req.BaseURL, req.APIKey, req.Proxy)
 	cfg.RatePerSecond, cfg.RatePerMinute = req.RatePerSecond, req.RatePerMinute
 	cfg.ThinkingType = req.ThinkingType
@@ -1455,6 +1461,14 @@ func (s *Server) testLLM(w http.ResponseWriter, r *http.Request) {
 			stored = p
 		}
 	}
+	if isMaskedSecret(req.Proxy) { // the form echoes the masked proxy: test with the stored one
+		req.Proxy = ""
+		if stored == nil {
+			s.cfgMu.Lock()
+			req.Proxy = s.llmCfg.Proxy
+			s.cfgMu.Unlock()
+		}
+	}
 	if stored != nil {
 		if strings.TrimSpace(req.Provider) == "" {
 			req.Provider = stored.Format
@@ -3487,8 +3501,10 @@ func (s *Server) settingsPayload() map[string]any {
 		"web_search_backend":       backend,
 		"brave_key_set":            strings.TrimSpace(braveKey) != "",
 		"tavily_key_set":           strings.TrimSpace(tavilyKey) != "",
-		"web_search_proxy":         proxy,                       // dedicated egress proxy (http/https/socks5), empty = direct
-		"global_proxy":             s.m.GlobalProxy(),           // global egress proxy (http/https/socks5), all target traffic goes through it, empty = direct
+		"web_search_proxy":         maskedSecret(proxy), // proxies may carry user:pass: masked when set, "" = direct
+		"web_search_proxy_set":     proxy != "",
+		"global_proxy":             maskedSecret(s.m.GlobalProxy()), // global egress proxy, masked when set, "" = direct
+		"global_proxy_set":         s.m.GlobalProxy() != "",
 		"python_interpreter":       strings.TrimSpace(pyStored), // user/auto-set value (empty = use runtime detection)
 		"workers":                  s.m.Workers(),               // number of concurrent worker agents (default 3); applies to tasks started afterwards
 		"task_concurrency_enabled": concOn,                      // task concurrency cap switch (default off)
@@ -3591,6 +3607,9 @@ func (s *Server) putSettings(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 400, err.Error())
 		return
 	}
+	// A masked placeholder echoed back keeps the stored secret, like null.
+	req.BraveKey, req.TavilyKey = keepIfMasked(req.BraveKey), keepIfMasked(req.TavilyKey)
+	req.WebSearchProxy, req.GlobalProxy = keepIfMasked(req.WebSearchProxy), keepIfMasked(req.GlobalProxy)
 	if req.ConstraintsInjectPlanner != nil {
 		if err := s.m.pg.SetBool(settingConstraintsInjectPlanner, *req.ConstraintsInjectPlanner); err != nil {
 			writeErr(w, 500, err.Error())
@@ -3788,13 +3807,17 @@ func (s *Server) testWebSearch(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 400, err.Error())
 		return
 	}
-	_, backend, storedBraveKey, storedTavilyKey, _ := s.m.WebSearch()
+	_, backend, storedBraveKey, storedTavilyKey, storedProxy := s.m.WebSearch()
 	if strings.TrimSpace(req.Backend) != "" {
 		backend = req.Backend
 	}
 	// Proxy is taken from the form as-is (empty = direct), so testing reflects exactly
 	// what's shown — including an intentional "clear proxy to test direct" before saving.
+	// The masked placeholder the form shows for a saved proxy means the saved one.
 	proxy := strings.TrimSpace(req.Proxy)
+	if isMaskedSecret(proxy) {
+		proxy = storedProxy
+	}
 	// API keys are secrets the form omits when already saved, so fall back to stored.
 	braveKey := storedBraveKey
 	if strings.TrimSpace(req.BraveKey) != "" {

server/server_mgmt.go

@@ -754,6 +754,11 @@ func (s *Server) pgListTools(w http.ResponseWriter, r *http.Request) {
 	if ts == nil {
 		ts = []*db.Tool{}
 	}
+	for _, tool := range ts {
+		if !tool.System {
+			tool.Exec = maskToolExec(tool.Exec)
+		}
+	}
 	// Usage is best-effort decoration. Runtime tool resolution keeps using the plain
 	// catalog query, so agent assembly never pays for this aggregate.
 	counts, countErr := pg.ToolUsageCounts()
@@ -864,6 +869,26 @@ func (s *Server) pgListMCP(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, 200, map[string]any{"servers": ms})
 }
 
+// maskedSecret is what a response shows for a stored secret such as a proxy
+// URL: the whole value is replaced by the placeholder, "" stays "".
+func maskedSecret(v string) string {
+	if v == "" {
+		return ""
+	}
+	return notify.MaskedPrefix
+}
+
+// isMaskedSecret reports a placeholder sent back on write: keep the stored value.
+func isMaskedSecret(v string) bool { return notify.IsMasked(strings.TrimSpace(v)) }
+
+// keepIfMasked turns a placeholder in an optional field into nil (keep).
+func keepIfMasked(v *string) *string {
+	if v != nil && isMaskedSecret(*v) {
+		return nil
+	}
+	return v
+}
+
 // maskMCPEnv replaces every non-empty env value (API keys, auth headers) with
 // notify.MaskedPrefix so the API never returns it in clear.
 func maskMCPEnv(raw json.RawMessage) json.RawMessage {
@@ -1949,6 +1974,16 @@ func (s *Server) pgSaveProfile(w http.ResponseWriter, r *http.Request) {
 	p := body.LLMProfile
 	p.APIKey = body.APIKey
 	p.Streaming = body.Streaming == nil || *body.Streaming
+	// The list returns the proxy masked: the placeholder sent back keeps the
+	// stored proxy and is never stored itself.
+	if isMaskedSecret(p.Proxy) {
+		stored, err := pg.ProfileByID(p.ID)
+		if p.ID == 0 || err != nil || stored == nil {
+			writeErr(w, 400, "proxy is a masked placeholder but no stored proxy to keep; enter the proxy or clear it")
+			return
+		}
+		p.Proxy = stored.Proxy
+	}
 	// Output cap: negative values are meaningless, clamp to zero (= do not send the
 	// field). The field-name switch only matters for Chat Completions — anthropic and
 	// openai-responses hard-code their field names; storing it would only mislead later readers, so it is cleared for any non-openai format. Unknown values are cleared too, to avoid throwing DB CHECK errors at the user.
@@ -2150,6 +2185,14 @@ func (s *Server) pgListModels(w http.ResponseWriter, r *http.Request) {
 			}
 		}
 	}
+	if isMaskedSecret(req.Proxy) { // the form echoes the masked proxy: use the stored one
+		req.Proxy = ""
+		if req.ProfileID != nil {
+			if p, err := s.m.pg.ProfileByID(*req.ProfileID); err == nil && p != nil {
+				req.Proxy = p.Proxy
+			}
+		}
+	}
 	provider := strings.TrimSpace(req.Provider)
 	// Ollama serves its model list keyless on the local server: no key gate.
 	if apiKey == "" && provider != "ollama" {

server/tools_secrets_api_test.go

@@ -0,0 +1,248 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync/atomic"
+	"testing"
+)
+
+// A placeholder keeps the stored secret only for the url and kind it was saved
+// with: a changed destination is refused before any write or request.
+func TestCustomToolExecDestinationGuard(t *testing.T) {
+	s, _, request := trafficEvidenceServer(t)
+	pg := s.m.PG()
+	var hits atomic.Int32
+	echo := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		hits.Add(1)
+		io.WriteString(w, "auth="+r.Header.Get("Authorization"))
+	}))
+	t.Cleanup(echo.Close)
+	t.Cleanup(func() { pg.Exec(`DELETE FROM tools WHERE key LIKE 't_secguard%'`) })
+	const secret = "Bearer guard-plain-0001"
+	schema := `{"type":"object","properties":{"q":{"type":"string"}}}`
+	body := func(kind, url, hdr string) string {
+		e, _ := json.Marshal(map[string]any{"method": "GET", "url": url, "headers": map[string]string{"Authorization": hdr}})
+		return `{"key":"t_secguard","kind":"` + kind + `","enabled":true,"schema":` + schema + `,"exec":` + string(e) + `}`
+	}
+	storedExec := func() (url, auth string) {
+		tl, err := pg.GetTool("t_secguard")
+		if err != nil || tl == nil {
+			t.Fatalf("GetTool: %v", err)
+		}
+		var e struct {
+			URL     string            `json:"url"`
+			Headers map[string]string `json:"headers"`
+		}
+		_ = json.Unmarshal(tl.Exec, &e)
+		return e.URL, e.Headers["Authorization"]
+	}
+	if resp := request("POST", "/api/tools/custom", body("http", echo.URL, secret)); resp.Code != 200 {
+		t.Fatalf("create: HTTP %d %s", resp.Code, resp.Body.String())
+	}
+	moved := echo.URL + "/elsewhere"
+
+	// 1. Masked header, changed url: refused, nothing written.
+	if resp := request("PUT", "/api/tools/custom/t_secguard", body("http", moved, "__masked__")); resp.Code != 400 {
+		t.Fatalf("masked header with a changed url must be refused, got HTTP %d", resp.Code)
+	}
+	if url, auth := storedExec(); url != echo.URL || auth != secret {
+		t.Fatalf("a refused update changed the stored exec: %s %s", url, auth)
+	}
+	// An empty url against a stored one is a change too.
+	if resp := request("PUT", "/api/tools/custom/t_secguard", body("http", "", "__masked__")); resp.Code != 400 {
+		t.Fatalf("masked header with an emptied url must be refused, got HTTP %d", resp.Code)
+	}
+
+	// 2. Masked header, same url: kept.
+	if resp := request("PUT", "/api/tools/custom/t_secguard", body("http", echo.URL, "__masked__")); resp.Code != 200 {
+		t.Fatalf("masked header with the same url: HTTP %d %s", resp.Code, resp.Body.String())
+	}
+	if url, auth := storedExec(); url != echo.URL || auth != secret {
+		t.Fatalf("the stored secret was not kept: %s %s", url, auth)
+	}
+
+	// 3. Test endpoint, masked header, changed url: refused, no request sent.
+	e, _ := json.Marshal(map[string]any{"method": "GET", "url": moved, "headers": map[string]string{"Authorization": "__masked__"}})
+	if resp := request("POST", "/api/tools/custom/test", `{"key":"t_secguard","kind":"http","exec":`+string(e)+`}`); resp.Code != 400 {
+		t.Fatalf("test endpoint with a changed url must be refused, got HTTP %d %s", resp.Code, resp.Body.String())
+	}
+	if n := hits.Load(); n != 0 {
+		t.Fatalf("the echo server received %d request(s); the stored secret left", n)
+	}
+
+	// 4. Kind change while keeping a placeholder: refused.
+	if resp := request("PUT", "/api/tools/custom/t_secguard", body("command", echo.URL, "__masked__")); resp.Code != 400 {
+		t.Fatalf("a kind change with a placeholder must be refused, got HTTP %d", resp.Code)
+	}
+	if tl, _ := pg.GetTool("t_secguard"); tl == nil || tl.Kind != "http" {
+		t.Fatalf("a refused kind change was written: %v", tl)
+	}
+
+	// 5. An explicit value with a changed url is allowed.
+	if resp := request("PUT", "/api/tools/custom/t_secguard", body("http", moved, "Bearer typed-0002")); resp.Code != 200 {
+		t.Fatalf("explicit header with a changed url: HTTP %d %s", resp.Code, resp.Body.String())
+	}
+	if url, auth := storedExec(); url != moved || auth != "Bearer typed-0002" {
+		t.Fatalf("explicit replace not stored: %s %s", url, auth)
+	}
+}
+
+// A custom tool's exec: headers, proxy and body are masked by GET /api/tools;
+// the placeholder keeps the stored value on update and in the test endpoint, a
+// create with it is refused, and the executor runs on the clear exec.
+func TestCustomToolExecMasking(t *testing.T) {
+	s, _, request := trafficEvidenceServer(t)
+	pg := s.m.PG()
+	echo := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		b, _ := io.ReadAll(r.Body)
+		io.WriteString(w, "auth="+r.Header.Get("Authorization")+" body="+string(b))
+	}))
+	t.Cleanup(echo.Close)
+	t.Cleanup(func() { pg.Exec(`DELETE FROM tools WHERE key LIKE 't_secexec%'`) })
+	secrets := []string{"hdr-plain-0001", "body-plain-0002", "proxy-plain-0003"}
+	schema := `{"type":"object","properties":{"q":{"type":"string"}}}`
+	execOf := func(hdr, body, proxy string) string {
+		e, _ := json.Marshal(map[string]any{"method": "POST", "url": echo.URL,
+			"headers": map[string]string{"Authorization": hdr, "X-Empty": ""}, "body": body, "proxy": proxy})
+		return string(e)
+	}
+	toolBody := func(key, exec string) string {
+		return `{"key":"` + key + `","kind":"http","enabled":true,"schema":` + schema + `,"exec":` + exec + `}`
+	}
+	stored := func() map[string]any {
+		tl, err := pg.GetTool("t_secexec")
+		if err != nil || tl == nil {
+			t.Fatalf("GetTool: %v", err)
+		}
+		var e map[string]any
+		_ = json.Unmarshal(tl.Exec, &e)
+		return e
+	}
+
+	plain := execOf("Bearer "+secrets[0], secrets[1], "http://u:"+secrets[2]+"@127.0.0.1:1")
+	if resp := request("POST", "/api/tools/custom", toolBody("t_secexec", plain)); resp.Code != 200 {
+		t.Fatalf("create: HTTP %d %s", resp.Code, resp.Body.String())
+	}
+	var raw string
+	if err := pg.QueryRow(`SELECT exec::text FROM tools WHERE key='t_secexec'`).Scan(&raw); err != nil || !strings.Contains(raw, "__artex_enc") {
+		t.Fatalf("exec not sealed at rest: %s %v", raw, err)
+	}
+
+	// List: masked with *_set flags, nothing in clear.
+	resp := request("GET", "/api/tools", "")
+	for _, sec := range secrets {
+		if resp.Code != 200 || strings.Contains(resp.Body.String(), sec) {
+			t.Fatalf("GET /api/tools: HTTP %d or a secret returned in clear", resp.Code)
+		}
+	}
+	var list struct {
+		Tools []struct {
+			Key  string          `json:"key"`
+			Exec json.RawMessage `json:"exec"`
+		}
+	}
+	_ = json.Unmarshal(resp.Body.Bytes(), &list)
+	var masked json.RawMessage
+	for _, tl := range list.Tools {
+		if tl.Key == "t_secexec" {
+			masked = tl.Exec
+		}
+	}
+	var m map[string]any
+	_ = json.Unmarshal(masked, &m)
+	h, _ := m["headers"].(map[string]any)
+	if h["Authorization"] != "__masked__" || h["X-Empty"] != "" || m["body"] != "__masked__" || m["proxy"] != "__masked__" ||
+		m["headers_set"] != true || m["body_set"] != true || m["proxy_set"] != true || m["url"] != echo.URL {
+		t.Fatalf("exec not masked as expected: %s", masked)
+	}
+
+	// Update echoing the masked exec: every stored value is kept, no flag stored.
+	if resp := request("PUT", "/api/tools/custom/t_secexec", toolBody("t_secexec", string(masked))); resp.Code != 200 {
+		t.Fatalf("update with placeholders: HTTP %d %s", resp.Code, resp.Body.String())
+	}
+	e := stored()
+	if e["headers"].(map[string]any)["Authorization"] != "Bearer "+secrets[0] || e["body"] != secrets[1] ||
+		!strings.Contains(e["proxy"].(string), secrets[2]) || e["body_set"] != nil {
+		t.Fatalf("placeholders did not keep the stored exec: %v", e)
+	}
+
+	// Test endpoint: the saved tool's key resolves the placeholders.
+	noProxy := execOf("__masked__", "__masked__", "")
+	if resp := request("POST", "/api/tools/custom/test", `{"kind":"http","exec":`+noProxy+`}`); resp.Code != 400 {
+		t.Fatalf("a placeholder without a saved tool must be refused, got HTTP %d", resp.Code)
+	}
+	resp = request("POST", "/api/tools/custom/test", `{"key":"t_secexec","kind":"http","exec":`+noProxy+`}`)
+	if resp.Code != 200 || !strings.Contains(resp.Body.String(), "auth=Bearer "+secrets[0]+" body="+secrets[1]) {
+		t.Fatalf("test endpoint did not use the stored values: HTTP %d %s", resp.Code, resp.Body.String())
+	}
+
+	// Replace the header, keep the body, clear the proxy.
+	if resp := request("PUT", "/api/tools/custom/t_secexec", toolBody("t_secexec", execOf("Bearer new-0004", "__masked__", ""))); resp.Code != 200 {
+		t.Fatalf("update: HTTP %d %s", resp.Code, resp.Body.String())
+	}
+	e = stored()
+	if e["headers"].(map[string]any)["Authorization"] != "Bearer new-0004" || e["body"] != secrets[1] || e["proxy"] != "" {
+		t.Fatalf("replace/keep/clear: %v", e)
+	}
+	if resp := request("GET", "/api/tools", ""); strings.Contains(resp.Body.String(), "new-0004") {
+		t.Fatal("a replaced secret is returned in clear")
+	}
+
+	// Create with a placeholder: refused, nothing written.
+	for _, ex := range []string{execOf("__masked__", "", ""), execOf("", "__masked__", ""), execOf("", "", "__masked__")} {
+		if resp := request("POST", "/api/tools/custom", toolBody("t_secexec_new", ex)); resp.Code != 400 {
+			t.Fatalf("create with a placeholder must be refused, got HTTP %d", resp.Code)
+		}
+	}
+	if tl, _ := pg.GetTool("t_secexec_new"); tl != nil {
+		t.Fatal("a refused create wrote a row")
+	}
+
+	// The executor receives the clear exec from the sealed row.
+	tools, err := s.customTools()
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, tl := range tools {
+		if tl.Name() != "t_secexec" {
+			continue
+		}
+		res, err := tl.Call(context.Background(), json.RawMessage(`{"q":"x"}`), nil)
+		if err != nil || !strings.Contains(res.Flatten(), "auth=Bearer new-0004 body="+secrets[1]) {
+			t.Fatalf("executor output %q %v", res.Flatten(), err)
+		}
+		return
+	}
+	t.Fatal("t_secexec not built by customTools")
+}
+
+// The platform tools follow the API: create refuses a placeholder, update keeps the stored value.
+func TestPlatformCustomToolPlaceholders(t *testing.T) {
+	s, _, _ := trafficEvidenceServer(t)
+	pg := s.m.PG()
+	t.Cleanup(func() { pg.Exec(`DELETE FROM tools WHERE key LIKE 't_secexec%'`) })
+	in := func(exec string) json.RawMessage {
+		return json.RawMessage(`{"key":"t_secexec_pt","kind":"command","exec":` + exec + `}`)
+	}
+	create, update := s.toolCreateCustomTool(), s.toolUpdateCustomTool()
+	if res, _ := create.Call(context.Background(), in(`{"command":"echo","proxy":"__masked__"}`), nil); !res.IsError {
+		t.Fatalf("create with a placeholder must fail: %s", res.Flatten())
+	}
+	if res, _ := create.Call(context.Background(), in(`{"command":"echo","body":"pt-body-plain"}`), nil); res.IsError {
+		t.Fatalf("create: %s", res.Flatten())
+	}
+	if res, _ := update.Call(context.Background(), in(`{"command":"echo 2","body":"__masked__"}`), nil); res.IsError {
+		t.Fatalf("update: %s", res.Flatten())
+	}
+	tl, err := pg.GetTool("t_secexec_pt")
+	if err != nil || tl == nil || !jsonHas(tl.Exec, "pt-body-plain") || !jsonHas(tl.Exec, "echo 2") {
+		t.Fatalf("update with a placeholder must keep the stored body: %v %v", tl, err)
+	}
+}
+
+func jsonHas(raw json.RawMessage, s string) bool { return strings.Contains(string(raw), s) }

web/src/app/(main)/system/tools/page.tsx

@@ -662,7 +662,8 @@ function CustomToolDialog({
     setTesting(true);
     setTestResult(null);
     try {
-      const r = await api.testCustomTool({ kind, exec: buildExec(), params });
+      // key: a saved tool's stored secrets replace the masked placeholders.
+      const r = await api.testCustomTool({ key: tool?.key, kind, exec: buildExec(), params });
       setTestResult(r);
     } catch (e) {
       setTestResult({ output: (e as Error).message, is_error: true });

web/src/lib/api.ts

@@ -1113,7 +1113,7 @@ export const api = {
     t: Pick<Tool, "description" | "schema" | "agents" | "enabled" | "kind" | "exec" | "deferred">,
   ) => put<{ ok: boolean }>(`/tools/custom/${key}`, t),
   deleteCustomTool: (key: string) => del<{ deleted: string }>(`/tools/custom/${key}`),
-  testCustomTool: (body: { kind: string; exec: Record<string, unknown>; params: Record<string, unknown> }) =>
+  testCustomTool: (body: { key?: string; kind: string; exec: Record<string, unknown>; params: Record<string, unknown> }) =>
     post<{ output: string; is_error: boolean }>("/tools/custom/test", body),
   detectPython: () => post<{ python_interpreter: string }>("/settings/python/detect", {}),