Add granular tool to set issue field values

pkg/github/__toolsnaps__/set_issue_fields.snap

@@ -0,0 +1,70 @@
+{
+  "annotations": {
+    "destructiveHint": false,
+    "openWorldHint": true,
+    "title": "Set Issue Fields"
+  },
+  "description": "Set issue field values for an issue. Fields are organization-level custom fields (text, number, date, or single select). Use this to create or update field values on an issue.",
+  "inputSchema": {
+    "properties": {
+      "fields": {
+        "description": "Array of issue field values to set. Each element must have a 'field_id' (string, the GraphQL node ID of the field) and exactly one value field: 'text_value' for text fields, 'number_value' for number fields, 'date_value' (ISO 8601 date string) for date fields, or 'single_select_option_id' (the GraphQL node ID of the option) for single select fields. Set 'delete' to true to remove a field value.",
+        "items": {
+          "properties": {
+            "date_value": {
+              "description": "The value to set for a date field (ISO 8601 date string)",
+              "type": "string"
+            },
+            "delete": {
+              "description": "Set to true to delete this field value",
+              "type": "boolean"
+            },
+            "field_id": {
+              "description": "The GraphQL node ID of the issue field",
+              "type": "string"
+            },
+            "number_value": {
+              "description": "The value to set for a number field",
+              "type": "number"
+            },
+            "single_select_option_id": {
+              "description": "The GraphQL node ID of the option to set for a single select field",
+              "type": "string"
+            },
+            "text_value": {
+              "description": "The value to set for a text field",
+              "type": "string"
+            }
+          },
+          "required": [
+            "field_id"
+          ],
+          "type": "object"
+        },
+        "minItems": 1,
+        "type": "array"
+      },
+      "issue_number": {
+        "description": "The issue number to update",
+        "minimum": 1,
+        "type": "number"
+      },
+      "owner": {
+        "description": "Repository owner (username or organization)",
+        "type": "string"
+      },
+      "repo": {
+        "description": "Repository name",
+        "type": "string"
+      }
+    },
+    "required": [
+      "owner",
+      "repo",
+      "issue_number",
+      "fields"
+    ],
+    "type": "object"
+  },
+  "name": "set_issue_fields"
+}

pkg/github/granular_tools_test.go

@@ -39,6 +39,7 @@ func TestGranularToolSnaps(t *testing.T) {
 		GranularAddSubIssue,
 		GranularRemoveSubIssue,
 		GranularReprioritizeSubIssue,
+		GranularSetIssueFields,
 		GranularUpdatePullRequestTitle,
 		GranularUpdatePullRequestBody,
 		GranularUpdatePullRequestState,
@@ -81,6 +82,7 @@ func TestIssuesGranularToolset(t *testing.T) {
 			"add_sub_issue",
 			"remove_sub_issue",
 			"reprioritize_sub_issue",
+			"set_issue_fields",
 		}
 		for _, name := range expected {
 			assert.Contains(t, toolNames, name)
@@ -774,3 +776,173 @@ func TestGranularUnresolveReviewThread(t *testing.T) {
 	require.NoError(t, err)
 	assert.False(t, result.IsError)
 }
+
+func TestGranularSetIssueFields(t *testing.T) {
+	t.Run("successful set with text value", func(t *testing.T) {
+		matchers := []githubv4mock.Matcher{
+			// Mock the issue ID query
+			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"},
+					},
+				}),
+			),
+			// Mock the setIssueFieldValue mutation
+			githubv4mock.NewMutationMatcher(
+				struct {
+					SetIssueFieldValue struct {
+						Issue struct {
+							ID     githubv4.ID
+							Number githubv4.Int
+							URL    githubv4.String
+						}
+						IssueFieldValues []struct {
+							Field struct {
+								Name string
+							} `graphql:"... on IssueFieldDateValue"`
+						}
+					} `graphql:"setIssueFieldValue(input: $input)"`
+				}{},
+				SetIssueFieldValueInput{
+					IssueID: githubv4.ID("ISSUE_123"),
+					IssueFields: []IssueFieldCreateOrUpdateInput{
+						{
+							FieldID:   githubv4.ID("FIELD_1"),
+							TextValue: githubv4.NewString(githubv4.String("hello")),
+						},
+					},
+				},
+				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"},
+			},
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		assert.False(t, result.IsError)
+	})
+
+	t.Run("missing required parameter fields", 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),
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		textContent := getTextResult(t, result)
+		assert.Contains(t, textContent.Text, "missing required parameter: fields")
+	})
+
+	t.Run("empty fields array", 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{},
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		textContent := getTextResult(t, result)
+		assert.Contains(t, textContent.Text, "fields array must not be empty")
+	})
+
+	t.Run("field missing value", 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"},
+			},
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		textContent := getTextResult(t, result)
+		assert.Contains(t, textContent.Text, "each field must have a value")
+	})
+
+	t.Run("multiple value keys 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", "number_value": float64(42)},
+			},
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		textContent := getTextResult(t, result)
+		assert.Contains(t, textContent.Text, "each field must have exactly one value")
+	})
+
+	t.Run("value key with delete 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", "delete": true},
+			},
+		})
+		result, err := handler(ContextWithDeps(context.Background(), deps), &request)
+		require.NoError(t, err)
+		textContent := getTextResult(t, result)
+		assert.Contains(t, textContent.Text, "each field must have exactly one value")
+	})
+}