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+// trios-server MCP service — the tool catalog and the call wrapper.
+// Port of gHashTag/trios:crates/trios-server/src/mcp.rs
+// (at 8b229e9489ee, 338 lines) — Roadmap Stage 6, goal #4548, target t27c
+// gen-rust.
+//
+// The original serves the trios tool catalog over MCP: `build_tool_definitions`
+// declares the nineteen tools (git basic and extended, gb, fs, kg), `prop_type`
+// and `prop_array_items` build the JSON-Schema property descriptors they
+// carry, `McpService::list_tools` answers the catalog, and
+// `McpService::call_tool` dispatches a call and wraps its result — a pretty
+// JSON text for object and array results, the string itself for strings,
+// compact JSON otherwise; an absent arguments map becomes JSON null; a
+// failed dispatch answers one text block prefixed "Error: " with
+// is_error set, a successful one the wrapped result with is_error unset.
+//
+// The serde_json maps, the LazyLock static and the dispatch await are
+// plumbing; the decisions the file makes — the property descriptors' shape
+// (a named type; an array of strings), the catalog's count and names, the
+// per-tool facts (which properties are required, which tool reads the
+// array descriptor, the git_log limit's integer type with its default of
+// 10), the list answer's shape (no meta, no next cursor), the
+// arguments-become-null rule, the result text kind selection, the error
+// flag and prefix, and the single content block — are ported here as pure
+// functions and tested. The McpService_call_tool transport keeps its name
+// with an `undefined;` body that no test calls (issue #9563, "Port the
+// decision, not the plumbing").
+//
+// Rust's `McpService` is a zero-sized struct; the port keeps the empty
+// struct shape and the `McpService_new` constructor that builds it.
+
+module port::trios_server_mcp;
+
+// ---------------------------------------------------------------------------
+// Original lines 13-24: `fn prop_type(type_str) -> Map` builds the JSON
+// property descriptor {"type": <type_str>}; `fn prop_array_items() -> Map`
+// builds {"type": "array", "items": {"type": "string"}}. The map keys are
+// the descriptor's shape: a named type, or an array whose items are
+// strings.
+// ---------------------------------------------------------------------------
+
+pub struct PropSchema {
+    type_name: str,
+    items_type_name: str,
+    is_array: bool,
+}
+
+pub fn prop_type(type_str: str) -> PropSchema {
+    return PropSchema { type_name: type_str, items_type_name: "", is_array: false };
+}
+
+pub fn prop_array_items() -> PropSchema {
+    return PropSchema { type_name: "array", items_type_name: "string", is_array: true };
+}
+
+// ---------------------------------------------------------------------------
+// Original lines 26-280: `fn build_tool_definitions() -> Vec<Tool>`. The
+// catalog: nineteen tools — nine git tools (status, stage_files,
+// unstage_files, commit, create_branch, log, diff, stash, checkout), three
+// gb tools (list_branches, push_stack, workspace_status), three fs tools
+// (read_file, write_file, list_dir) and four kg tools (create_entity,
+// create_edge, query, traverse). The growable Vec is plumbing; the count
+// and the names are the decisions, ported below. The per-tool facts the
+// original fixes: git_status requires one property (repo_path, a string)
+// and describes itself as listing every changed file; git_stage_files
+// takes two required properties with the paths property read through the
+// array descriptor; git_log's limit property is an integer defaulting
+// to 10.
+// ---------------------------------------------------------------------------
+
+pub fn build_tool_definitions() -> usize {
+    return 19;
+}
+
+pub fn tool_name(index: usize) -> str {
+    if (index == 0) { return "git_status"; }
+    if (index == 1) { return "git_stage_files"; }
+    if (index == 2) { return "git_unstage_files"; }
+    if (index == 3) { return "git_commit"; }
+    if (index == 4) { return "git_create_branch"; }
+    if (index == 5) { return "git_log"; }
+    if (index == 6) { return "git_diff"; }
+    if (index == 7) { return "git_stash"; }
+    if (index == 8) { return "git_checkout"; }
+    if (index == 9) { return "gb_list_branches"; }
+    if (index == 10) { return "gb_push_stack"; }
+    if (index == 11) { return "gb_workspace_status"; }
+    if (index == 12) { return "fs_read_file"; }
+    if (index == 13) { return "fs_write_file"; }
+    if (index == 14) { return "fs_list_dir"; }
+    if (index == 15) { return "kg_create_entity"; }
+    if (index == 16) { return "kg_create_edge"; }
+    if (index == 17) { return "kg_query"; }
+    if (index == 18) { return "kg_traverse"; }
+    return "";
+}
+
+pub fn git_status_description() -> str {
+    return "List all changed files in a repository";
+}
+
+pub fn git_status_required_count() -> usize {
+    return 1;
+}
+
+pub fn git_status_property_count() -> usize {
+    return 1;
+}
+
+pub fn git_stage_files_required_count() -> usize {
+    return 2;
+}
+
+pub fn git_stage_files_has_array_property() -> bool {
+    return true;
+}
+
+pub fn git_log_limit_property_type() -> str {
+    return "integer";
+}
+
+pub fn git_log_limit_default() -> usize {
+    return 10;
+}
+
+// ---------------------------------------------------------------------------
+// Original lines 281-295: `impl McpService { pub fn new() -> Self; pub fn
+// list_tools(&self) -> ListToolsResult }`. The service is a zero-sized
+// struct; the list answer carries the whole catalog with no meta and no
+// next cursor.
+// ---------------------------------------------------------------------------
+
+pub struct McpService { }
+
+pub fn McpService_new() -> McpService {
+    return McpService { };
+}
+
+pub struct ListToolsView {
+    tool_count: usize,
+    meta_present: bool,
+    next_cursor_present: bool,
+}
+
+pub fn McpService_list_tools(service: McpService) -> ListToolsView {
+    return ListToolsView {
+        tool_count: build_tool_definitions(),
+        meta_present: false,
+        next_cursor_present: false,
+    };
+}
+
+// ---------------------------------------------------------------------------
+// Original lines 297-337: `pub async fn call_tool(&self, params) ->
+// CallToolResult`. Dispatches the named tool and wraps the result. The
+// dispatch await is plumbing; the decisions are ported below: an absent
+// arguments map becomes JSON null; a successful object or array result is
+// rendered as pretty JSON text, a string result as the string itself,
+// anything else as compact JSON; the answer is exactly one text content
+// block; a failed dispatch prefixes the error text with "Error: " and sets
+// is_error.
+// ---------------------------------------------------------------------------
+
+pub fn McpService_call_tool(service: McpService, tool_name: str, has_arguments: bool) -> ?str {
+    return undefined; // plumbing: dispatches to tools::dispatch and wraps the result (lines 297-337)
+}
+
+pub fn arguments_become_null(has_arguments: bool) -> bool {
+    if (!has_arguments) {
+        return true;
+    }
+    return false;
+}
+
+pub fn result_text_kind(is_object: bool, is_array: bool, is_string: bool) -> str {
+    if (is_object or is_array) {
+        return "pretty";
+    }
+    if (is_string) {
+        return "string";
+    }
+    return "compact";
+}
+
+pub fn call_result_is_error(dispatch_ok: bool) -> bool {
+    if (!dispatch_ok) {
+        return true;
+    }
+    return false;
+}
+
+pub fn error_text_prefix() -> str {
+    return "Error: ";
+}
+
+pub fn content_block_count() -> usize {
+    return 1;
+}
+
+// ---------------------------------------------------------------------------
+// Tests: every decision above asserted against values read from the
+// original. No test calls the call_tool transport.
+// ---------------------------------------------------------------------------
+
+test prop_type_carries_the_named_type {
+    const p = prop_type("string");
+    assert(p.type_name == "string");
+    assert(p.items_type_name == "");
+    assert(!p.is_array);
+}
+
+test prop_array_items_is_an_array_of_strings {
+    const a = prop_array_items();
+    assert(a.type_name == "array");
+    assert(a.items_type_name == "string");
+    assert(a.is_array);
+}
+
+test tool_catalog_nineteen_names {
+    assert(build_tool_definitions() == 19);
+    assert(tool_name(0) == "git_status");
+    assert(tool_name(8) == "git_checkout");
+    assert(tool_name(11) == "gb_workspace_status");
+    assert(tool_name(12) == "fs_read_file");
+    assert(tool_name(18) == "kg_traverse");
+    assert(tool_name(19) == "");
+}
+
+test git_status_tool_facts {
+    assert(git_status_description() == "List all changed files in a repository");
+    assert(git_status_required_count() == 1);
+    assert(git_status_property_count() == 1);
+}
+
+test git_stage_files_reads_the_array_descriptor {
+    assert(git_stage_files_required_count() == 2);
+    assert(git_stage_files_has_array_property());
+}
+
+test git_log_limit_defaults_to_ten {
+    assert(git_log_limit_property_type() == "integer");
+    assert(git_log_limit_default() == 10);
+}
+
+test service_lists_the_whole_catalog {
+    const view = McpService_list_tools(McpService_new());
+    assert(view.tool_count == 19);
+    assert(!view.meta_present);
+    assert(!view.next_cursor_present);
+}
+
+test call_tool_argument_and_text_kinds {
+    assert(arguments_become_null(false));
+    assert(!arguments_become_null(true));
+    assert(result_text_kind(true, false, false) == "pretty");
+    assert(result_text_kind(false, true, false) == "pretty");
+    assert(result_text_kind(false, false, true) == "string");
+    assert(result_text_kind(false, false, false) == "compact");
+}
+
+test call_tool_error_wrapping {
+    assert(!call_result_is_error(true));
+    assert(call_result_is_error(false));
+    assert(error_text_prefix() == "Error: ");
+    assert(content_block_count() == 1);
+}