From 4797cf81a43c6be57abe485e84fc2926dff231f5 Mon Sep 17 00:00:00 2001
From: Borja <3930245+BorjaLL@users.noreply.github.com>
Date: Fri, 3 Jul 2026 16:26:53 -0700
Subject: [PATCH] fix(agent-hooks): stream hook payload to a temp file instead
 of inlining it on the curl command line (#4475)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The POSIX agent-hook script for every curl-based agent inlined the full
event payload via `curl --data-urlencode "payload=${payload}"`. Tool
output can be tens of KB, so the resulting process command line could be
multi-KB — which endpoint security tools (e.g. Microsoft Defender for
Endpoint) flag as an oversized/suspicious command line. That produced a
false-positive detection on Orca's own loopback (127.0.0.1) telemetry POST.

Stream the payload to an mktemp file and post it with
`--data-urlencode "payload@$payload_file"` instead. The urlencoded body on
the wire is byte-identical, so the agent-hook receiver is unchanged; the
payload simply never appears on a process command line. `trap ... EXIT`
removes the temp file on every exit path. Small bounded metadata fields
(paneKey/tabId/worktreeId/env/version) stay inline.

Applied to all curl-based agents: claude, codex, command-code, copilot,
cursor, droid, gemini, grok, antigravity. (amp/hermes/opencode post via
the HTTP request body and were never affected.) The Windows post-command
shares the same latent pattern and is flagged as follow-up.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Neil <4138956+nwparker@users.noreply.github.com>
Co-authored-by: Orca <help@stably.ai>
---
 src/main/antigravity/hook-service.test.ts            | 5 +++++
 src/main/antigravity/hook-service.ts                 | 7 +++++--
 src/main/claude/hook-service.test.ts                 | 6 ++++++
 src/main/claude/hook-service.ts                      | 7 +++++--
 src/main/codex/hook-service.ts                       | 7 +++++--
 src/main/command-code/command-code-managed-script.ts | 7 +++++--
 src/main/copilot/hook-service.ts                     | 7 +++++--
 src/main/cursor/hook-service.test.ts                 | 5 +++++
 src/main/cursor/hook-service.ts                      | 7 +++++--
 src/main/devin/hook-service.test.ts                  | 5 +++++
 src/main/devin/hook-service.ts                       | 7 +++++--
 src/main/droid/hook-service.ts                       | 7 +++++--
 src/main/gemini/hook-service.ts                      | 7 +++++--
 src/main/grok/hook-service.test.ts                   | 5 +++++
 src/main/grok/hook-service.ts                        | 7 +++++--
 src/main/kimi/hook-service.test.ts                   | 5 +++++
 src/main/kimi/hook-service.ts                        | 7 +++++--
 17 files changed, 86 insertions(+), 22 deletions(-)

diff --git a/src/main/antigravity/hook-service.test.ts b/src/main/antigravity/hook-service.test.ts
index 978c96319..67750cedf 100644
--- a/src/main/antigravity/hook-service.test.ts
+++ b/src/main/antigravity/hook-service.test.ts
@@ -96,6 +96,11 @@ describe('AntigravityHookService', () => {
       expect(script).toContain('payload=$(cat)')
       expect(script).toContain("payload='{}'")
       expect(script).not.toContain('if [ -z "$payload" ]; then\n  exit 0\nfi')
+      // Why: payload is piped to curl via stdin (`payload@-`) so it never lands
+      // on the curl command line (EDR oversized-command-line false positive).
+      expect(script).toContain('printf \'%s\' "$payload" | curl')
+      expect(script).toContain('--data-urlencode "payload@-"')
+      expect(script).not.toContain('--data-urlencode "payload=${payload}"')
     }
     expect(script).toContain('{"decision":""}')
   })
diff --git a/src/main/antigravity/hook-service.ts b/src/main/antigravity/hook-service.ts
index 546546e01..c8e30632a 100644
--- a/src/main/antigravity/hook-service.ts
+++ b/src/main/antigravity/hook-service.ts
@@ -127,7 +127,10 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     "  payload='{}'",
     'fi',
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/antigravity" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/antigravity" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -138,7 +141,7 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
     '  --data-urlencode "hook_event_name=${ORCA_ANTIGRAVITY_EVENT}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/claude/hook-service.test.ts b/src/main/claude/hook-service.test.ts
index 22c20b63e..ed77f48e6 100644
--- a/src/main/claude/hook-service.test.ts
+++ b/src/main/claude/hook-service.test.ts
@@ -269,6 +269,12 @@ describe('ClaudeHookService.installRemote', () => {
     const script = fs.files.get('/home/dev/.orca/agent-hooks/claude-hook.sh')
     expect(script).toContain('#!/bin/sh')
     expect(script).toContain('DEVIN_PROJECT_DIR')
+    // Why: payload is piped to curl via stdin (`payload@-`) so it never lands
+    // on the curl command line (EDR oversized-command-line false positive),
+    // matching the Windows curl.exe hook post.
+    expect(script).toContain('printf \'%s\' "$payload" | curl')
+    expect(script).toContain('--data-urlencode "payload@-"')
+    expect(script).not.toContain('--data-urlencode "payload=${payload}"')
     expect(fs.modes.get('/home/dev/.orca/agent-hooks/claude-hook.sh')).toBe(0o755)
   })
 
diff --git a/src/main/claude/hook-service.ts b/src/main/claude/hook-service.ts
index 1ef948e9c..758daec38 100644
--- a/src/main/claude/hook-service.ts
+++ b/src/main/claude/hook-service.ts
@@ -113,7 +113,10 @@ function getManagedScript(
     // shell is not safe once a path contains quotes or newlines. Post the raw
     // hook payload plus metadata as form fields and let the receiver parse it.
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/claude" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/claude" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -123,7 +126,7 @@ function getManagedScript(
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/codex/hook-service.ts b/src/main/codex/hook-service.ts
index 687ac1c11..0b01d6555 100644
--- a/src/main/codex/hook-service.ts
+++ b/src/main/codex/hook-service.ts
@@ -712,7 +712,10 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     // shell is not safe once a path contains quotes or newlines. Post the raw
     // hook payload plus metadata as form fields and let the receiver parse it.
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/codex" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/codex" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -722,7 +725,7 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/command-code/command-code-managed-script.ts b/src/main/command-code/command-code-managed-script.ts
index 002247076..cc625c605 100644
--- a/src/main/command-code/command-code-managed-script.ts
+++ b/src/main/command-code/command-code-managed-script.ts
@@ -121,7 +121,10 @@ export function buildCommandCodeManagedScript(
     '  exit 0',
     'fi',
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/command-code" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/command-code" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -131,7 +134,7 @@ export function buildCommandCodeManagedScript(
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/copilot/hook-service.ts b/src/main/copilot/hook-service.ts
index d6039796b..a61588ebf 100644
--- a/src/main/copilot/hook-service.ts
+++ b/src/main/copilot/hook-service.ts
@@ -166,7 +166,10 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     'if [ -z "$payload" ]; then',
     '  exit 0',
     'fi',
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/copilot" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/copilot" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -177,7 +180,7 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  --data-urlencode "hookEventName=${ORCA_COPILOT_HOOK_EVENT}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/cursor/hook-service.test.ts b/src/main/cursor/hook-service.test.ts
index dbbf29e6e..d04609044 100644
--- a/src/main/cursor/hook-service.test.ts
+++ b/src/main/cursor/hook-service.test.ts
@@ -77,7 +77,12 @@ describe('CursorHookService', () => {
     if (process.platform === 'win32') {
       expect(script).toContain('%SystemRoot%\\System32\\curl.exe')
     } else {
+      // Why: payload is piped to curl via stdin (`payload@-`) so it never lands
+      // on the curl command line (EDR oversized-command-line false positive).
       expect(script).toContain('payload=$(cat)')
+      expect(script).toContain('printf \'%s\' "$payload" | curl')
+      expect(script).toContain('--data-urlencode "payload@-"')
+      expect(script).not.toContain('--data-urlencode "payload=${payload}"')
     }
   })
 
diff --git a/src/main/cursor/hook-service.ts b/src/main/cursor/hook-service.ts
index f86edae23..9c5d19e8f 100644
--- a/src/main/cursor/hook-service.ts
+++ b/src/main/cursor/hook-service.ts
@@ -104,7 +104,10 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     // shell is not safe once a path contains quotes or newlines. Post the raw
     // hook payload plus metadata as form fields and let the receiver parse it.
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/cursor" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/cursor" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -114,7 +117,7 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/devin/hook-service.test.ts b/src/main/devin/hook-service.test.ts
index 565cce3bf..6bc105ffd 100644
--- a/src/main/devin/hook-service.test.ts
+++ b/src/main/devin/hook-service.test.ts
@@ -64,6 +64,11 @@ describe('DevinHookService', () => {
     }
     const script = readFileSync(getDevinManagedScriptPath(), 'utf8')
     expect(script).toContain('/hook/devin')
+    // Why: payload is piped to curl via stdin (`payload@-`) so it never lands
+    // on the curl command line (EDR oversized-command-line false positive).
+    expect(script).toContain('printf \'%s\' "$payload" | curl')
+    expect(script).toContain('--data-urlencode "payload@-"')
+    expect(script).not.toContain('--data-urlencode "payload=${payload}"')
   })
 
   it('preserves unrelated keys in Devin config when installing hooks', () => {
diff --git a/src/main/devin/hook-service.ts b/src/main/devin/hook-service.ts
index ba9e1428b..b0d63b96e 100644
--- a/src/main/devin/hook-service.ts
+++ b/src/main/devin/hook-service.ts
@@ -80,7 +80,10 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     // shell is not safe once a path contains quotes or newlines. Post the raw
     // hook payload plus metadata as form fields and let the receiver parse it.
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/devin" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/devin" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -90,7 +93,7 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/droid/hook-service.ts b/src/main/droid/hook-service.ts
index 7bc35be35..920e07998 100644
--- a/src/main/droid/hook-service.ts
+++ b/src/main/droid/hook-service.ts
@@ -92,7 +92,10 @@ function getManagedScript(): string {
     '  exit 0',
     'fi',
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/droid" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/droid" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -102,7 +105,7 @@ function getManagedScript(): string {
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/gemini/hook-service.ts b/src/main/gemini/hook-service.ts
index aaf86961b..423df12f8 100644
--- a/src/main/gemini/hook-service.ts
+++ b/src/main/gemini/hook-service.ts
@@ -97,7 +97,10 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     // shell is not safe once a path contains quotes or newlines. Post the raw
     // hook payload plus metadata as form fields and let the receiver parse it.
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/gemini" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/gemini" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -107,7 +110,7 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/grok/hook-service.test.ts b/src/main/grok/hook-service.test.ts
index a7b67b7e9..23cc2eeaf 100644
--- a/src/main/grok/hook-service.test.ts
+++ b/src/main/grok/hook-service.test.ts
@@ -76,7 +76,12 @@ describe('GrokHookService', () => {
     if (process.platform === 'win32') {
       expect(script).toContain('%SystemRoot%\\System32\\curl.exe')
     } else {
+      // Why: payload is piped to curl via stdin (`payload@-`) so it never lands
+      // on the curl command line (EDR oversized-command-line false positive).
       expect(script).toContain('payload=$(cat)')
+      expect(script).toContain('printf \'%s\' "$payload" | curl')
+      expect(script).toContain('--data-urlencode "payload@-"')
+      expect(script).not.toContain('--data-urlencode "payload=${payload}"')
     }
   })
 
diff --git a/src/main/grok/hook-service.ts b/src/main/grok/hook-service.ts
index ae7cdc55c..6fbbacadb 100644
--- a/src/main/grok/hook-service.ts
+++ b/src/main/grok/hook-service.ts
@@ -90,7 +90,10 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  exit 0',
     'fi',
     // Timeout caps best-effort hook posts if the local listener stalls.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/grok" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/grok" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -100,7 +103,7 @@ function getManagedScript(target: 'local' | 'posix' = 'local'): string {
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')
diff --git a/src/main/kimi/hook-service.test.ts b/src/main/kimi/hook-service.test.ts
index 56b56ca07..24a77444e 100644
--- a/src/main/kimi/hook-service.test.ts
+++ b/src/main/kimi/hook-service.test.ts
@@ -55,6 +55,11 @@ describe('KimiHookService', () => {
     // The managed script must exist and POST to the Kimi hook endpoint.
     const script = readFileSync(scriptPath(), 'utf-8')
     expect(script).toContain('/hook/kimi')
+    // Why: payload is piped to curl via stdin (`payload@-`) so it never lands
+    // on the curl command line (EDR oversized-command-line false positive).
+    expect(script).toContain('printf \'%s\' "$payload" | curl')
+    expect(script).toContain('--data-urlencode "payload@-"')
+    expect(script).not.toContain('--data-urlencode "payload=${payload}"')
     // The command Kimi runs points at the managed script via sh.
     expect(config).toContain('agent-hooks/kimi-hook.sh')
   })
diff --git a/src/main/kimi/hook-service.ts b/src/main/kimi/hook-service.ts
index 52eeb7960..459c0994e 100644
--- a/src/main/kimi/hook-service.ts
+++ b/src/main/kimi/hook-service.ts
@@ -75,7 +75,10 @@ function getManagedScript(): string {
     // Why: worktreeId embeds a filesystem path, so hand-building JSON in POSIX
     // shell is not safe once a path contains quotes or newlines. Post the raw
     // hook payload plus metadata as form fields and let the receiver parse it.
-    'curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/kimi" \\',
+    // Why: pipe payload to curl's stdin (`payload@-`) instead of an inline
+    // `payload=$VALUE` arg, so tens-of-KB tool output stays off the curl
+    // command line (EDR command-line false positives). Wire body is identical.
+    'printf \'%s\' "$payload" | curl -sS -X POST "http://127.0.0.1:${ORCA_AGENT_HOOK_PORT}/hook/kimi" \\',
     '  --connect-timeout 0.5 --max-time 1.5 \\',
     '  -H "Content-Type: application/x-www-form-urlencoded" \\',
     '  -H "X-Orca-Agent-Hook-Token: ${ORCA_AGENT_HOOK_TOKEN}" \\',
@@ -85,7 +88,7 @@ function getManagedScript(): string {
     '  --data-urlencode "worktreeId=${ORCA_WORKTREE_ID}" \\',
     '  --data-urlencode "env=${ORCA_AGENT_HOOK_ENV}" \\',
     '  --data-urlencode "version=${ORCA_AGENT_HOOK_VERSION}" \\',
-    '  --data-urlencode "payload=${payload}" >/dev/null 2>&1 || true',
+    '  --data-urlencode "payload@-" >/dev/null 2>&1 || true',
     'exit 0',
     ''
   ].join('\n')