docs(mcp): name the upcoming periods in the get_cycle description

The cycle read returns the projected period starts after the next one,
each with its band, under upcoming; the tool description for MCP clients
and the Coach did not say so.

src/lib/ai/coach/tools/__tests__/__snapshots__/coach-turn-tool-defs.snap

@@ -184,7 +184,7 @@
   },
   {
     "name": "get_cycle",
-    "description": "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Returns { present: false } when cycle tracking is off or there is no data.",
+    "description": "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, the upcoming period starts after it (`upcoming`: each a likely start with its earliest-to-latest band, widening and self-capped), and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Returns { present: false } when cycle tracking is off or there is no data.",
     "parameters": {
       "type": "object",
       "additionalProperties": false,

src/lib/ai/coach/tools/definitions.ts

@@ -366,7 +366,7 @@ export const COACH_TOOL_DEFS: AiToolDef[] = [
   {
     name: "get_cycle",
     description:
-      "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Returns { present: false } when cycle tracking is off or there is no data.",
+      "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, the upcoming period starts after it (`upcoming`: each a likely start with its earliest-to-latest band, widening and self-capped), and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Returns { present: false } when cycle tracking is off or there is no data.",
     parameters: {
       type: "object",
       additionalProperties: false,

src/lib/mcp/__tests__/__snapshots__/tools-list.write-session.snap

@@ -1844,7 +1844,7 @@
   {
     "name": "get_cycle",
     "title": "Get menstrual cycle",
-    "description": "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Gated on cycle tracking being enabled for the account; returns { present: false } when cycle tracking is off or there is no data.",
+    "description": "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, the upcoming period starts after it (`upcoming`: each a likely start with its earliest-to-latest band, widening and self-capped), and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Gated on cycle tracking being enabled for the account; returns { present: false } when cycle tracking is off or there is no data.",
     "inputSchema": {
       "type": "object",
       "properties": {}

src/lib/mcp/__tests__/tools.test.ts

@@ -326,6 +326,11 @@ describe("MCP tool registry — surface", () => {
     }
   });
 
+  it("tells a client that get_cycle returns the upcoming periods", () => {
+    const def = MCP_TOOLS.find((t) => t.name === "get_cycle");
+    expect(def?.description).toContain("`upcoming`");
+  });
+
   it("annotates every tool read-only / closed-world (cloud-connector requirement)", () => {
     for (const def of MCP_TOOLS) {
       expect(def.annotations.readOnlyHint).toBe(true);

src/lib/mcp/tools/get-cycle.ts

@@ -6,7 +6,7 @@ export const getCycleTool: McpToolDefinition = {
   name: "get_cycle",
   title: "Get menstrual cycle",
   description:
-    "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Gated on cycle tracking being enabled for the account; returns { present: false } when cycle tracking is off or there is no data.",
+    "Fetch the user's menstrual-cycle context: current phase + day-of-cycle, the next predicted event, the upcoming period starts after it (`upcoming`: each a likely start with its earliest-to-latest band, widening and self-capped), and the headline phase-correlation finding. Descriptive only — never a contraception-grade or 'safe day' claim. Gated on cycle tracking being enabled for the account; returns { present: false } when cycle tracking is off or there is no data.",
   inputShape: {},
   annotations: READ_ONLY_ANNOTATIONS,
   outputShape: coachReadOutput,