chenhg5/cc-connect · error

hook input exceeds %d bytes

Error message

hook input exceeds %d bytes

What it means

Relay enforces a 4 MiB cap (maxHookInput) on the hook's stdin payload and returns 'hook input exceeds %d bytes' when the JSON invocation exceeds it. Oversized payloads are rejected before any network call so the bridge is never flooded.

Source

Thrown at agent/antigravityhook/protocol.go:42

}

type BridgeResponse struct {
	Decision string `json:"decision"`
	Reason   string `json:"reason,omitempty"`
}

// Relay forwards one Agy hook invocation to the owning cc-connect session.
func Relay(in io.Reader, out io.Writer, address, token string) error {
	if strings.TrimSpace(address) == "" || strings.TrimSpace(token) == "" {
		return fmt.Errorf("permission bridge environment is missing")
	}

	input, err := io.ReadAll(io.LimitReader(in, maxHookInput+1))
	if err != nil {
		return fmt.Errorf("read hook input: %w", err)
	}
	if len(input) > maxHookInput {
		return fmt.Errorf("hook input exceeds %d bytes", maxHookInput)
	}
	if !json.Valid(input) {
		return fmt.Errorf("hook input is not valid JSON")
	}

	conn, err := net.DialTimeout("tcp", address, bridgeDialTimeout)
	if err != nil {
		return fmt.Errorf("connect permission bridge: %w", err)
	}
	defer func() { _ = conn.Close() }()
	// The listener is started before agy runs this hook, so dial failures should
	// fail closed quickly. After connect, wait much longer for a human response.
	_ = conn.SetDeadline(time.Now().Add(bridgeResponseTimeout))

	if err := json.NewEncoder(conn).Encode(BridgeRequest{Token: token, HookInput: input}); err != nil {
		return fmt.Errorf("send permission request: %w", err)
	}

View on GitHub (pinned to 4000b2338a)

Solutions

1. Reduce the size of the prompt/context attached to the agy turn that triggers the hook
2. Upgrade or fix agy if it is inflating hook input beyond the spec
3. If legitimately needed, raise maxHookInput in agent/antigravityhook/protocol.go and rebuild
4. Check for runaway loops appending to the hook input upstream

data, _ := io.ReadAll(in)
if len(data) > 4<<20 {
    return fmt.Errorf("hook input is %d bytes; max is %d", len(data), 4<<20)
}

if err := Relay(...); err != nil && strings.Contains(err.Error(), "exceeds") {
    fmt.Fprintln(os.Stderr, "payload too large: shrink prompt/context")
    os.Exit(2)
}

When it happens

Trigger: Agy invokes the permission hook with a hook input document larger than 4194304 bytes — e.g. a prompt/context blob embedded in the hook input that grew huge.

Common situations: Extremely large prompts or attached context in the permission request; a modified/buggy agy version emitting extra fields; users piping artificially large files into the hook when testing.

Understand the failure class

Background: payload too large / request exceeds maximum size: why libraries cap bytes and how to fix oversize payloads — this error's family across 50 libraries.

Related errors

• Content-Length too large: %d
• permission bridge environment is missing
• read hook input: %w
• hook input is not valid JSON
• download exceeds --max-bytes: %d > %d

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/5900eeda024b8f74. Report an issue: GitHub.