Match Water Profile

Instructions

Implementation Reference

• src/tools/match-water-profile.ts:27-83 (handler)

  The main handler function 'registerMatchWaterProfile' that registers the 'match_water_profile' tool on the MCP server. It implements a 3-strategy search: (1) fuzzy search water profiles by name/city, (2) fuzzy search by bestFor (style) field, (3) search styles and cross-reference with water profiles. Returns formatted text with mineral composition and style recommendations.

  export function registerMatchWaterProfile(server: McpServer): void {
    server.registerTool(
      "match_water_profile",
      {
        title: "Match Water Profile",
        description:
          "Find brewing water profiles by city name or beer style. Returns mineral composition (Ca, Mg, Na, Cl, SO4, HCO3) and style recommendations.",
        inputSchema: {
          query: z
            .string()
            .describe("City name or beer style to find water profile for"),
        },
      },
      async ({ query }) => {
        // Strategy 1: search water profiles by name/city
        let results = fuzzySearch(WATER_PROFILES, query, ["name", "city"]);
  
        // Strategy 2: if no direct match, search by bestFor (style name)
        if (results.length === 0 && query.trim()) {
          results = fuzzySearch(WATER_PROFILES, query, ["bestFor"]);
        }
  
        // Strategy 3: if still no match, search styles first, then find water profiles for those styles
        if (results.length === 0 && query.trim()) {
          const matchedStyles = fuzzySearch(STYLES, query, ["name", "category"]);
          if (matchedStyles.length > 0) {
            const styleNames = matchedStyles.map((s) => s.name.toLowerCase());
            results = WATER_PROFILES.filter((wp) =>
              wp.bestFor.some((bf) =>
                styleNames.some((sn) => bf.toLowerCase().includes(sn) || sn.includes(bf.toLowerCase())),
              ),
            );
          }
        }
  
        if (results.length === 0) {
          return {
            content: [
              {
                type: "text" as const,
                text: `No water profiles found matching '${query}'. Try a city name (e.g. 'Burton', 'Dublin') or beer style (e.g. 'IPA', 'Pilsner').`,
              },
            ],
          };
        }
  
        return {
          content: [
            {
              type: "text" as const,
              text: results.map(formatProfile).join("\n\n---\n\n"),
            },
          ],
        };
      },
    );
  }

• src/tools/match-water-profile.ts:30-38 (schema)

  Input schema for the 'match_water_profile' tool. Uses Zod to define a single required string parameter 'query' described as 'City name or beer style to find water profile for'.

  {
    title: "Match Water Profile",
    description:
      "Find brewing water profiles by city name or beer style. Returns mineral composition (Ca, Mg, Na, Cl, SO4, HCO3) and style recommendations.",
    inputSchema: {
      query: z
        .string()
        .describe("City name or beer style to find water profile for"),
    },

• src/register-tools.ts:5-5 (registration)

  Import statement that pulls in the registerMatchWaterProfile function from the tools module.

  import { registerMatchWaterProfile } from "./tools/match-water-profile.js";

• src/register-tools.ts:13-13 (registration)

  Registration call that passes the MCP server instance to registerMatchWaterProfile, wiring the tool into the server.

  registerMatchWaterProfile(server);

• src/tools/match-water-profile.ts:8-25 (helper)

  Helper function 'formatProfile' that formats a WaterProfile object into a human-readable Markdown string including name, city, mineral composition (Ca, Mg, Na, Cl, SO4, HCO3), sulfate:chloride ratio, description, and style recommendations.

  function formatProfile(wp: WaterProfile): string {
    const ratio =
      wp.chloride > 0
        ? (wp.sulfate / wp.chloride).toFixed(1)
        : wp.sulfate > 0
          ? "∞"
          : "0.0";
    return [
      `## ${wp.name} (${wp.city})`,
      `Ca: ${wp.calcium} | Mg: ${wp.magnesium} | Na: ${wp.sodium}`,
      `Cl: ${wp.chloride} | SO4: ${wp.sulfate} | HCO3: ${wp.bicarbonate}`,
      `Sulfate:Chloride ratio: ${ratio}`,
      "",
      wp.description,
      "",
      `Best for: ${wp.bestFor.join(", ")}`,
    ].join("\n");
  }