Add is_suggestion + rationale to update_issue_assignees

docs/feature-flags.md

@@ -150,7 +150,7 @@ runtime behavior (such as output formatting) won't appear here.
 
 - **update_issue_assignees** - Update Issue Assignees
   - **Required OAuth Scopes**: `repo`
-  - `assignees`: GitHub usernames to assign to this issue (string[], required)
+  - `assignees`: GitHub usernames to assign to this issue. ([], required)
   - `issue_number`: The issue number to update (number, required)
   - `owner`: Repository owner (username or organization) (string, required)
   - `repo`: Repository name (string, required)

pkg/github/__toolsnaps__/update_issue_assignees.snap

@@ -6,13 +6,48 @@
     "readOnlyHint": false,
     "title": "Update Issue Assignees"
   },
-  "description": "Update the assignees of an existing issue. This replaces the current assignees with the provided list.",
+  "description": "Update the assignees of an existing issue. This replaces the current assignees with the provided list. When setting values, include a confidence level (LOW, MEDIUM, or HIGH) reflecting how certain you are about the choice.",
   "inputSchema": {
     "properties": {
       "assignees": {
-        "description": "GitHub usernames to assign to this issue",
+        "description": "GitHub usernames to assign to this issue.",
         "items": {
-          "type": "string"
+          "oneOf": [
+            {
+              "description": "GitHub username",
+              "type": "string"
+            },
+            {
+              "properties": {
+                "confidence": {
+                  "description": "How confident you are in this choice. Use 'HIGH' for clear signal or explicit user request, 'MEDIUM' for reasonable inference with some ambiguity, 'LOW' for best guess with limited signal.",
+                  "enum": [
+                    "LOW",
+                    "MEDIUM",
+                    "HIGH"
+                  ],
+                  "type": "string"
+                },
+                "is_suggestion": {
+                  "description": "If true, this assignee is sent to the API as a suggestion (suggest:true) rather than an applied assignee. Whether the assignee is applied or recorded as a proposal is determined by the API.",
+                  "type": "boolean"
+                },
+                "login": {
+                  "description": "GitHub username",
+                  "type": "string"
+                },
+                "rationale": {
+                  "description": "One concise sentence explaining what specifically about the issue led you to choose this assignee. State the concrete signal (e.g. 'Authored the file the crash originates in').",
+                  "maxLength": 280,
+                  "type": "string"
+                }
+              },
+              "required": [
+                "login"
+              ],
+              "type": "object"
+            }
+          ]
         },
         "type": "array"
       },

pkg/github/granular_tools_test.go

@@ -271,6 +271,167 @@ func TestGranularUpdateIssueAssignees(t *testing.T) {
 	assert.False(t, result.IsError)
 }
 
+func TestGranularUpdateIssueAssigneesObjectForm(t *testing.T) {
+	tests := []struct {
+		name        string
+		requestArgs map[string]any
+		expectedReq map[string]any
+	}{
+		{
+			name: "assignee objects without intent serialize as strings",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees": []any{
+					map[string]any{"login": "octocat"},
+					"monalisa",
+				},
+			},
+			expectedReq: map[string]any{
+				"assignees": []any{"octocat", "monalisa"},
+			},
+		},
+		{
+			name: "assignee suggested without rationale",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees": []any{
+					map[string]any{"login": "octocat", "is_suggestion": true},
+				},
+			},
+			expectedReq: map[string]any{
+				"assignees": []any{
+					map[string]any{"login": "octocat", "suggest": true},
+				},
+			},
+		},
+		{
+			name: "suggested assignee with rationale and confidence",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees": []any{
+					map[string]any{"login": "octocat", "rationale": "  Authored the crashing file  ", "confidence": "high", "is_suggestion": true},
+				},
+			},
+			expectedReq: map[string]any{
+				"assignees": []any{
+					map[string]any{"login": "octocat", "rationale": "Authored the crashing file", "confidence": "HIGH", "suggest": true},
+				},
+			},
+		},
+		{
+			name: "mix of plain and suggested assignees",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees": []any{
+					"monalisa",
+					map[string]any{"login": "octocat", "is_suggestion": true},
+				},
+			},
+			expectedReq: map[string]any{
+				"assignees": []any{
+					"monalisa",
+					map[string]any{"login": "octocat", "suggest": true},
+				},
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			client := mustNewGHClient(t, MockHTTPClientWithHandlers(map[string]http.HandlerFunc{
+				PatchReposIssuesByOwnerByRepoByIssueNumber: expectRequestBody(t, tc.expectedReq).
+					andThen(mockResponse(t, http.StatusOK, &gogithub.Issue{Number: gogithub.Ptr(1)})),
+			}))
+			deps := BaseDeps{Client: client}
+			serverTool := GranularUpdateIssueAssignees(translations.NullTranslationHelper)
+			handler := serverTool.Handler(deps)
+
+			request := createMCPRequest(tc.requestArgs)
+			result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+			require.NoError(t, err)
+			assert.False(t, result.IsError)
+		})
+	}
+}
+
+func TestGranularUpdateIssueAssigneesInvalidInput(t *testing.T) {
+	tests := []struct {
+		name            string
+		requestArgs     map[string]any
+		expectedErrText string
+	}{
+		{
+			name: "rationale too long",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees": []any{
+					map[string]any{"login": "octocat", "rationale": strings.Repeat("a", 281)},
+				},
+			},
+			expectedErrText: "assignee rationale must be 280 characters or less",
+		},
+		{
+			name: "assignee object missing login",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees": []any{
+					map[string]any{"rationale": "no login provided"},
+				},
+			},
+			expectedErrText: "each assignee object must have a 'login' string",
+		},
+		{
+			name: "invalid confidence value",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees": []any{
+					map[string]any{"login": "octocat", "confidence": "maybe"},
+				},
+			},
+			expectedErrText: "confidence must be one of: LOW, MEDIUM, HIGH",
+		},
+		{
+			name: "assignee entry is neither string nor object",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"assignees":    []any{float64(123)},
+			},
+			expectedErrText: "each assignee must be a string or an object",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			deps := BaseDeps{Client: mustNewGHClient(t, MockHTTPClientWithHandlers(nil))}
+			serverTool := GranularUpdateIssueAssignees(translations.NullTranslationHelper)
+			handler := serverTool.Handler(deps)
+
+			request := createMCPRequest(tc.requestArgs)
+			result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+			require.NoError(t, err)
+
+			errorContent := getErrorResult(t, result)
+			assert.Contains(t, errorContent.Text, tc.expectedErrText)
+		})
+	}
+}
+
 func TestGranularUpdateIssueLabels(t *testing.T) {
 	tests := []struct {
 		name        string