Adding rationale for fields and labels in issues_granular

pkg/github/__toolsnaps__/set_issue_fields.snap

@@ -27,6 +27,11 @@
               "description": "The value to set for a number field",
               "type": "number"
             },
+            "rationale": {
+              "description": "One concise sentence explaining what specifically about the issue led you to choose this field value. State the concrete signal (e.g. 'Reports a crash when saving' → high priority).",
+              "maxLength": 280,
+              "type": "string"
+            },
             "single_select_option_id": {
               "description": "The GraphQL node ID of the option to set for a single select field",
               "type": "string"

pkg/github/__toolsnaps__/update_issue_labels.snap

@@ -13,9 +13,31 @@
         "type": "number"
       },
       "labels": {
-        "description": "Labels to apply to this issue",
+        "description": "Labels to apply to this issue.",
         "items": {
-          "type": "string"
+          "oneOf": [
+            {
+              "description": "Label name",
+              "type": "string"
+            },
+            {
+              "properties": {
+                "name": {
+                  "description": "Label name",
+                  "type": "string"
+                },
+                "rationale": {
+                  "description": "One concise sentence explaining what specifically about the issue led you to choose this label. State the concrete signal (e.g. 'Reports a crash when saving' → bug).",
+                  "maxLength": 280,
+                  "type": "string"
+                }
+              },
+              "required": [
+                "name"
+              ],
+              "type": "object"
+            }
+          ]
         },
         "type": "array"
       },

pkg/github/granular_tools_test.go

@@ -263,24 +263,124 @@ func TestGranularUpdateIssueAssignees(t *testing.T) {
 }
 
 func TestGranularUpdateIssueLabels(t *testing.T) {
-	client := mustNewGHClient(t, MockHTTPClientWithHandlers(map[string]http.HandlerFunc{
-		PatchReposIssuesByOwnerByRepoByIssueNumber: expectRequestBody(t, map[string]any{
-			"labels": []any{"bug", "enhancement"},
-		}).andThen(mockResponse(t, http.StatusOK, &gogithub.Issue{Number: gogithub.Ptr(1)})),
-	}))
-	deps := BaseDeps{Client: client}
-	serverTool := GranularUpdateIssueLabels(translations.NullTranslationHelper)
-	handler := serverTool.Handler(deps)
+	tests := []struct {
+		name        string
+		requestArgs map[string]any
+		expectedReq map[string]any
+	}{
+		{
+			name: "labels as plain strings",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"labels":       []any{"bug", "enhancement"},
+			},
+			expectedReq: map[string]any{
+				"labels": []any{"bug", "enhancement"},
+			},
+		},
+		{
+			name: "label objects without rationale serialize as strings",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"labels": []any{
+					map[string]any{"name": "bug"},
+					"enhancement",
+				},
+			},
+			expectedReq: map[string]any{
+				"labels": []any{"bug", "enhancement"},
+			},
+		},
+		{
+			name: "mixed strings and label objects with rationale",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"labels": []any{
+					"triage",
+					map[string]any{"name": "bug", "rationale": "  Reports a crash when saving  "},
+					map[string]any{"name": "frontend", "rationale": "Mentions the UI button"},
+				},
+			},
+			expectedReq: map[string]any{
+				"labels": []any{
+					"triage",
+					map[string]any{"name": "bug", "rationale": "Reports a crash when saving"},
+					map[string]any{"name": "frontend", "rationale": "Mentions the UI button"},
+				},
+			},
+		},
+	}
 
-	request := createMCPRequest(map[string]any{
-		"owner":        "owner",
-		"repo":         "repo",
-		"issue_number": float64(1),
-		"labels":       []string{"bug", "enhancement"},
-	})
-	result, err := handler(ContextWithDeps(context.Background(), deps), &request)
-	require.NoError(t, err)
-	assert.False(t, result.IsError)
+	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 := GranularUpdateIssueLabels(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 TestGranularUpdateIssueLabelsInvalidRationale(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),
+				"labels": []any{
+					map[string]any{"name": "bug", "rationale": strings.Repeat("a", 281)},
+				},
+			},
+			expectedErrText: "label rationale must be 280 characters or less",
+		},
+		{
+			name: "label object missing name",
+			requestArgs: map[string]any{
+				"owner":        "owner",
+				"repo":         "repo",
+				"issue_number": float64(1),
+				"labels": []any{
+					map[string]any{"rationale": "no name provided"},
+				},
+			},
+			expectedErrText: "each label object must have a 'name' string",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			deps := BaseDeps{Client: mustNewGHClient(t, MockHTTPClientWithHandlers(nil))}
+			serverTool := GranularUpdateIssueLabels(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 TestGranularUpdateIssueMilestone(t *testing.T) {
@@ -1034,4 +1134,117 @@ func TestGranularSetIssueFields(t *testing.T) {
 		textContent := getTextResult(t, result)
 		assert.Contains(t, textContent.Text, "each field must have exactly one value")
 	})
+
+	t.Run("successful set with text value and rationale", func(t *testing.T) {
+		matchers := []githubv4mock.Matcher{
+			githubv4mock.NewQueryMatcher(
+				struct {
+					Repository struct {
+						Issue struct {
+							ID githubv4.ID
+						} `graphql:"issue(number: $issueNumber)"`
+					} `graphql:"repository(owner: $owner, name: $repo)"`
+				}{},
+				map[string]any{
+					"owner":       githubv4.String("owner"),
+					"repo":        githubv4.String("repo"),
+					"issueNumber": githubv4.Int(5),
+				},
+				githubv4mock.DataResponse(map[string]any{
+					"repository": map[string]any{
+						"issue": map[string]any{"id": "ISSUE_123"},
+					},
+				}),
+			),
+			githubv4mock.NewMutationMatcher(
+				struct {
+					SetIssueFieldValue struct {
+						Issue struct {
+							ID     githubv4.ID
+							Number githubv4.Int
+							URL    githubv4.String
+						}
+						IssueFieldValues []struct {
+							TextValue struct {
+								Value string
+							} `graphql:"... on IssueFieldTextValue"`
+							SingleSelectValue struct {
+								Name string
+							} `graphql:"... on IssueFieldSingleSelectValue"`
+							DateValue struct {
+								Value string
+							} `graphql:"... on IssueFieldDateValue"`
+							NumberValue struct {
+								Value float64
+							} `graphql:"... on IssueFieldNumberValue"`
+						}
+					} `graphql:"setIssueFieldValue(input: $input)"`
+				}{},
+				SetIssueFieldValueInput{
+					IssueID: githubv4.ID("ISSUE_123"),
+					IssueFields: []IssueFieldCreateOrUpdateInput{
+						{
+							FieldID:   githubv4.ID("FIELD_1"),
+							TextValue: githubv4.NewString(githubv4.String("hello")),
+							Rationale: githubv4.NewString(githubv4.String("Reflects the reported severity")),
+						},
+					},
+				},
+				nil,
+				githubv4mock.DataResponse(map[string]any{
+					"setIssueFieldValue": map[string]any{
+						"issue": map[string]any{
+							"id":     "ISSUE_123",
+							"number": 5,
+							"url":    "https://github.com/owner/repo/issues/5",
+						},
+					},
+				}),
+			),
+		}
+
+		gqlClient := githubv4.NewClient(githubv4mock.NewMockedHTTPClient(matchers...))
+		deps := BaseDeps{GQLClient: gqlClient}
+		serverTool := GranularSetIssueFields(translations.NullTranslationHelper)
+		handler := serverTool.Handler(deps)
+
+		request := createMCPRequest(map[string]any{
+			"owner":        "owner",
+			"repo":         "repo",
+			"issue_number": float64(5),
+			"fields": []any{
+				map[string]any{
+					"field_id":   "FIELD_1",
+					"text_value": "hello",
+					"rationale":  "  Reflects the reported severity  ",
+				},
+			},
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		assert.False(t, result.IsError)
+	})
+
+	t.Run("rationale too long returns error", func(t *testing.T) {
+		deps := BaseDeps{}
+		serverTool := GranularSetIssueFields(translations.NullTranslationHelper)
+		handler := serverTool.Handler(deps)
+
+		request := createMCPRequest(map[string]any{
+			"owner":        "owner",
+			"repo":         "repo",
+			"issue_number": float64(5),
+			"fields": []any{
+				map[string]any{
+					"field_id":   "FIELD_1",
+					"text_value": "hello",
+					"rationale":  strings.Repeat("a", 281),
+				},
+			},
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		textContent := getTextResult(t, result)
+		assert.Contains(t, textContent.Text, "field rationale must be 280 characters or less")
+	})
 }