#!/usr/bin/env bash
# Tools handler implementation.
# Error responses use JSON-RPC 2.0 codes (for example, -32601 method not found,
# -32602 invalid params, -32603 internal error).
set -euo pipefail
mcp_tools_extract_call_fields() {
# Extract name, arguments (compact JSON), timeoutSecs, and _meta.
# Uses separate jq calls to avoid @tsv double-escaping backslashes which
# corrupts JSON containing escaped quotes (e.g., Status in ["New", "Intro"]).
# See: docs/internal/PLAN-silent-args-parsing-failures.md
local json_payload="$1"
local name args_json timeout_override meta_json
local _extract_failed=false
name="$(printf '%s' "${json_payload}" | "${MCPBASH_JSON_TOOL_BIN}" -r '.params.name // ""' 2>/dev/null)" || {
name=""
_extract_failed=true
}
args_json="$(printf '%s' "${json_payload}" | "${MCPBASH_JSON_TOOL_BIN}" -c '.params.arguments // {}' 2>/dev/null)" || {
args_json="{}"
_extract_failed=true
}
timeout_override="$(printf '%s' "${json_payload}" | "${MCPBASH_JSON_TOOL_BIN}" -r '(.params.timeoutSecs // null) | tostring' 2>/dev/null)" || {
timeout_override="null"
_extract_failed=true
}
meta_json="$(printf '%s' "${json_payload}" | "${MCPBASH_JSON_TOOL_BIN}" -c '.params._meta // {}' 2>/dev/null)" || {
meta_json="{}"
_extract_failed=true
}
# Log extraction failures for debugging
if [ "${_extract_failed}" = "true" ] && declare -F mcp_logging_warning >/dev/null 2>&1; then
mcp_logging_warning "${MCP_TOOLS_LOGGER:-mcp.tools}" "Call field extraction failed: payload_len=${#json_payload}"
fi
# Output tab-separated (no @tsv escaping - direct printf)
printf '%s\t%s\t%s\t%s' "${name}" "${args_json}" "${timeout_override}" "${meta_json}"
}
mcp_handle_tools() {
local method="$1"
local json_payload="$2"
local id
if ! id="$(mcp_json_extract_id "${json_payload}")"; then
id="null"
fi
if mcp_runtime_is_minimal_mode; then
local message
message=$(mcp_json_quote_text "Tools capability unavailable in minimal mode")
mcp_handler_error_response "${id}" "-32601" "${message}"
return 0
fi
case "${method}" in
tools/list)
local limit cursor
limit="$(mcp_json_extract_limit "${json_payload}")"
cursor="$(mcp_json_extract_cursor "${json_payload}")"
local list_json
if ! list_json="$(mcp_tools_list "${limit}" "${cursor}")"; then
local code
code="$(mcp_handler_normalize_error_code "${_MCP_TOOLS_ERROR_CODE:-}")"
local message
message=$(mcp_json_quote_text "${_MCP_TOOLS_ERROR_MESSAGE:-Unable to list tools}")
local data="${_MCP_TOOLS_ERROR_DATA:-}"
mcp_handler_error_response "${id}" "${code}" "${message}" "${data}"
return 0
fi
mcp_handler_success_response "${id}" "${list_json}"
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "${MCP_TOOLS_LOGGER}" "List count=${MCP_TOOLS_TOTAL}"
fi
;;
tools/call)
local name args_json timeout_override meta_json
# Extract fields in one JSON-tool pass; keep args and _meta as compact JSON
extraction="$(mcp_tools_extract_call_fields "${json_payload}")"
# Debug: log extraction length before read
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "${MCP_TOOLS_LOGGER}" "Extraction len=${#extraction}"
fi
IFS=$'\t' read -r name args_json timeout_override meta_json <<<"${extraction}"
[ -z "${args_json}" ] && args_json="{}"
[ -z "${meta_json}" ] && meta_json="{}"
# Debug: log field lengths after read to detect truncation
if mcp_logging_is_enabled "debug"; then
mcp_logging_debug "${MCP_TOOLS_LOGGER}" "After read: name_len=${#name} args_len=${#args_json}"
fi
# Normalize "null" placeholders to empty strings
[ "${timeout_override}" = "null" ] && timeout_override=""
if [ -z "${name}" ]; then
local message
message=$(mcp_json_quote_text "Tool name is required")
mcp_handler_error_response "${id}" "-32602" "${message}"
return 0
fi
# Validate args_json is valid JSON before passing to tool
if ! printf '%s' "${args_json}" | "${MCPBASH_JSON_TOOL_BIN}" -e . >/dev/null 2>&1; then
mcp_logging_error "${MCP_TOOLS_LOGGER}" "Invalid args JSON for tool=${name}: ${args_json:0:100}..."
local message
message=$(mcp_json_quote_text "Invalid arguments JSON")
mcp_handler_error_response "${id}" "-32602" "${message}"
return 0
fi
local result_json
if ! mcp_tools_call "${name}" "${args_json}" "${timeout_override}" "${meta_json}"; then
result_json="${_MCP_TOOLS_RESULT:-}"
# Parse error info from stdout (mcp_tools_call emits error JSON on failure)
local code=-32603 message_raw="Tool execution failed" data="null"
if [ -n "${result_json}" ] && [ "${MCPBASH_JSON_TOOL:-none}" != "none" ]; then
# Check if it's a tool error object with _mcpToolError marker
local is_tool_error
is_tool_error="$(printf '%s' "${result_json}" | "${MCPBASH_JSON_TOOL_BIN}" -r '._mcpToolError // empty' 2>/dev/null || true)"
if [ "${is_tool_error}" = "true" ]; then
code="$(printf '%s' "${result_json}" | "${MCPBASH_JSON_TOOL_BIN}" -r '.code // -32603')"
message_raw="$(printf '%s' "${result_json}" | "${MCPBASH_JSON_TOOL_BIN}" -r '.message // "Tool execution failed"')"
data="$(printf '%s' "${result_json}" | "${MCPBASH_JSON_TOOL_BIN}" -c '.data // null')"
fi
fi
# Normalize code
code="$(mcp_handler_normalize_error_code "${code}")"
local message
message=$(mcp_json_quote_text "${message_raw}")
mcp_logging_debug "${MCP_TOOLS_LOGGER}" "tools/call error code=${code} message=${message_raw} data=${data:-<unset>}" || true
mcp_handler_error_response "${id}" "${code}" "${message}" "${data}"
return 0
fi
result_json="${_MCP_TOOLS_RESULT}"
mcp_handler_success_response "${id}" "${result_json}"
;;
*)
local message
message=$(mcp_json_quote_text "Unknown tools method")
mcp_handler_error_response "${id}" "-32601" "${message}"
;;
esac
}
