FedRAMP Docs MCP Server

Instructions

Implementation Reference

• src/tools/diff_frmr.ts:20-24 (handler)

  The execute function implementing the core logic of the 'diff_frmr' tool, which calls diffFrmrDocuments with the input parameters.

  execute: async (input) => {
    return diffFrmrDocuments(input.left_path, input.right_path, {
      idKey: input.id_key,
    });
  },

• src/tools/diff_frmr.ts:6-10 (schema)

  Zod input schema for the 'diff_frmr' tool defining left_path, right_path, and optional id_key.

  const schema = z.object({
    left_path: z.string(),
    right_path: z.string(),
    id_key: z.string().optional(),
  });

• src/tools/register.ts:24-53 (registration)

  The registerTools function registers the 'diff_frmr' tool (imported as diffFrmrTool) by including it in the array passed to registerToolDefs.

  export function registerTools(server: McpServer): void {
    registerToolDefs(server, [
      // Document discovery
      listFrmrDocumentsTool,
      getFrmrDocumentTool,
      listVersionsTool,
      // KSI tools
      listKsiTool,
      getKsiTool,
      filterByImpactTool,
      getThemeSummaryTool,
      getEvidenceExamplesTool,
      // Control mapping tools
      listControlsTool,
      getControlRequirementsTool,
      analyzeControlCoverageTool,
      // Search & lookup tools
      searchMarkdownTool,
      readMarkdownTool,
      searchDefinitionsTool,
      getRequirementByIdTool,
      // Analysis tools
      diffFrmrTool,
      grepControlsTool,
      significantChangeTool,
      // System tools
      healthCheckTool,
      updateRepositoryTool,
    ]);
  }

• src/diff.ts:81-153 (helper)

  The diffFrmrDocuments helper function that computes the structured diff between two FRMR documents, handling additions, removals, and modifications.

  export function diffFrmrDocuments(
    leftPath: string,
    rightPath: string,
    options: DiffOptions = {},
  ): DiffResult {
    const leftDoc = resolveFrmrDocument(leftPath);
    const rightDoc = resolveFrmrDocument(rightPath);
    if (!leftDoc || !rightDoc) {
      throw createError({
        code: "NOT_FOUND",
        message: "One or both FRMR documents could not be found in the index.",
      });
    }
  
    const idKey = getIdKey(options, leftDoc, rightDoc);
  
    const leftItems = extractItems(leftDoc);
    const rightItems = extractItems(rightDoc);
  
    const leftMap = toMap(leftItems, idKey);
    const rightMap = toMap(rightItems, idKey);
  
    const changes: DiffChange[] = [];
  
    for (const [id, rightValue] of rightMap.entries()) {
      if (!leftMap.has(id)) {
        changes.push({
          type: "added",
          id,
          title:
            typeof rightValue.title === "string" ? rightValue.title : undefined,
        });
      }
    }
  
    for (const [id, leftValue] of leftMap.entries()) {
      if (!rightMap.has(id)) {
        changes.push({
          type: "removed",
          id,
          title:
            typeof leftValue.title === "string" ? leftValue.title : undefined,
        });
        continue;
      }
      const rightValue = rightMap.get(id)!;
      const fields = detectChangedFields(leftValue, rightValue, idKey);
      if (fields.length) {
        changes.push({
          type: "modified",
          id,
          title:
            typeof rightValue.title === "string"
              ? rightValue.title
              : typeof leftValue.title === "string"
                ? leftValue.title
                : undefined,
          fields,
        });
      }
    }
  
    const summary = {
      added: changes.filter((change) => change.type === "added").length,
      removed: changes.filter((change) => change.type === "removed").length,
      modified: changes.filter((change) => change.type === "modified").length,
    };
  
    return {
      summary,
      changes,
    };
  }