#!/usr/bin/env bash
# Lifecycle handler: initialize/initialized/shutdown workflow.
# Error responses use JSON-RPC 2.0 codes (e.g., -32600 invalid request,
# -32601 method not found, -32602 invalid params).
set -euo pipefail
mcp_handle_lifecycle() {
local method="$1"
local json_payload="$2"
local id
if ! id="$(mcp_json_extract_id "${json_payload}")"; then
id="null"
fi
case "${method}" in
initialize)
if [ "${MCPBASH_INITIALIZE_HANDSHAKE_DONE}" = true ]; then
printf '{"jsonrpc":"2.0","id":%s,"error":{"code":-32600,"message":"Server already initialized"}}' "${id}"
return 0
fi
local requested_version=""
requested_version="$(mcp_json_extract_protocol_version "${json_payload}")"
local negotiated_version=""
if ! negotiated_version="$(mcp_spec_resolve_protocol_version "${requested_version}")"; then
local supported_list
supported_list="$(mcp_spec_supported_protocols | tr ' ' ', ')"
local err_msg
err_msg="$(printf 'Unsupported protocol version: %s. Supported: %s' "${requested_version:-<none>}" "${supported_list}")"
err_msg="$(mcp_json_quote_text "${err_msg}")"
printf '{"jsonrpc":"2.0","id":%s,"error":{"code":-32602,"message":%s}}' "${id}" "${err_msg}"
return 0
fi
# shellcheck disable=SC2034
MCPBASH_NEGOTIATED_PROTOCOL_VERSION="${negotiated_version}"
if [ -n "${requested_version}" ] && [ "${requested_version}" != "${negotiated_version}" ]; then
printf '%s\n' "Degraded protocol to ${negotiated_version} per client request." >&2
fi
local capabilities
capabilities="$(mcp_spec_capabilities_for_runtime "${negotiated_version}")"
MCPBASH_INITIALIZE_HANDSHAKE_DONE=true
MCPBASH_INITIALIZED=false
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "mcp.lifecycle" "Initialize requested=${requested_version} negotiated=${negotiated_version}"
fi
# Log client identity for debugging (single jq pass per json-handling.mdc)
if mcp_logging_is_enabled "debug"; then
local client_info client_name client_version
client_info="$(printf '%s' "${json_payload}" | "${MCPBASH_JSON_TOOL_BIN}" -r '[(.params.clientInfo.name // "unknown"), (.params.clientInfo.version // "?")] | @tsv' 2>/dev/null || printf 'unknown\t?')"
client_name="${client_info%% *}"
client_version="${client_info#* }"
mcp_logging_debug "mcp.lifecycle" "Client: ${client_name}/${client_version} pid=$$"
fi
local client_caps="{}"
if [ "${MCPBASH_JSON_TOOL:-none}" != "none" ]; then
client_caps="$(printf '%s' "${json_payload}" | "${MCPBASH_JSON_TOOL_BIN}" -c '.params.capabilities // {}' 2>/dev/null || printf '{}')"
fi
mcp_elicitation_init "${client_caps}"
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "mcp.lifecycle" "Elicitation support=${MCPBASH_CLIENT_SUPPORTS_ELICITATION}"
fi
mcp_roots_capture_capabilities "${client_caps}"
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "mcp.lifecycle" "Roots support=${MCPBASH_CLIENT_SUPPORTS_ROOTS} listChanged=${MCPBASH_CLIENT_SUPPORTS_ROOTS_LIST_CHANGED}"
fi
printf '%s' "$(mcp_spec_build_initialize_response "${id}" "${capabilities}" "${negotiated_version}")"
;;
notifications/initialized | initialized)
# shellcheck disable=SC2034
MCPBASH_INITIALIZED=true
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "mcp.lifecycle" "Initialized handshake complete"
fi
mcp_roots_init_after_initialized
printf '%s' "${MCPBASH_NO_RESPONSE}"
;;
shutdown)
MCPBASH_SHUTDOWN_PENDING=true
if [ "${MCPBASH_SHUTDOWN_TIMER_STARTED:-false}" != "true" ]; then
MCPBASH_SHUTDOWN_TIMER_STARTED=true
mcp_core_start_shutdown_watchdog
fi
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "mcp.lifecycle" "Shutdown requested"
fi
printf '{"jsonrpc":"2.0","id":%s,"result":{}}' "${id}"
;;
exit)
if [ "${MCPBASH_SHUTDOWN_PENDING}" != "true" ]; then
if [ "${id}" = "null" ]; then
printf '%s' "${MCPBASH_NO_RESPONSE}"
return 0
fi
printf '{"jsonrpc":"2.0","id":%s,"error":{"code":-32005,"message":"Shutdown not requested"}}' "${id}"
return 0
fi
mcp_core_cancel_shutdown_watchdog
MCPBASH_SHUTDOWN_TIMER_STARTED=false
# shellcheck disable=SC2034
MCPBASH_EXIT_REQUESTED=true
if [ "${id}" = "null" ]; then
printf '%s' "${MCPBASH_NO_RESPONSE}"
else
printf '{"jsonrpc":"2.0","id":%s,"result":{}}' "${id}"
fi
;;
*)
printf '{"jsonrpc":"2.0","id":%s,"error":{"code":-32601,"message":"Unknown lifecycle method"}}' "${id}"
;;
esac
}
