Get a single ISM control

Instructions

Implementation Reference

• src/index.ts:295-340 (handler)

  The get_control tool handler: resolves the version, loads flattened controls, matches by controlId (OSCAL id or label), and returns full control detail in JSON or Markdown format.

  server.registerTool(
    "get_control",
    {
      title: "Get a single ISM control",
      description:
        "Returns the full detail (title, group path, applicability, statement) for a single ISM control. Accepts either the OSCAL id (e.g. ism-principle-gov-01) or the human label (e.g. GOV-01).",
      inputSchema: {
        controlId: z
          .string()
          .describe(
            'Either OSCAL id (e.g. "ism-principle-gov-01") or label (e.g. "GOV-01").',
          ),
        version: z.string().optional(),
        format: z.enum(["json", "markdown"]).optional(),
      },
    },
    async ({ controlId, version, format }) => {
      const v = await resolveVersion(version);
      const flat = await loadFlat(v.tag);
      const match = findControlMatch(flat, controlId);
      if (!match) {
        return {
          isError: true,
          content: [
            {
              type: "text",
              text: `No control matched "${controlId}" in ISM ${v.id}.`,
            },
          ],
        };
      }
      if (format === "markdown") {
        return txt(controlToMarkdown(match, v.id));
      }
      return txt({
        version: v.id,
        id: match.id,
        label: match.label,
        title: match.title,
        section: match.groupPath,
        applicability: match.applicability,
        statement: match.statement,
        raw: match.raw,
      });
    },
  );

• src/index.ts:295-340 (registration)

  Registration of the get_control tool with the MCP server, including title, description, and input schema.

  server.registerTool(
    "get_control",
    {
      title: "Get a single ISM control",
      description:
        "Returns the full detail (title, group path, applicability, statement) for a single ISM control. Accepts either the OSCAL id (e.g. ism-principle-gov-01) or the human label (e.g. GOV-01).",
      inputSchema: {
        controlId: z
          .string()
          .describe(
            'Either OSCAL id (e.g. "ism-principle-gov-01") or label (e.g. "GOV-01").',
          ),
        version: z.string().optional(),
        format: z.enum(["json", "markdown"]).optional(),
      },
    },
    async ({ controlId, version, format }) => {
      const v = await resolveVersion(version);
      const flat = await loadFlat(v.tag);
      const match = findControlMatch(flat, controlId);
      if (!match) {
        return {
          isError: true,
          content: [
            {
              type: "text",
              text: `No control matched "${controlId}" in ISM ${v.id}.`,
            },
          ],
        };
      }
      if (format === "markdown") {
        return txt(controlToMarkdown(match, v.id));
      }
      return txt({
        version: v.id,
        id: match.id,
        label: match.label,
        title: match.title,
        section: match.groupPath,
        applicability: match.applicability,
        statement: match.statement,
        raw: match.raw,
      });
    },
  );

• src/index.ts:301-309 (schema)

  Input schema for get_control: requires controlId string, optional version string, and optional format enum (json/markdown).

  inputSchema: {
    controlId: z
      .string()
      .describe(
        'Either OSCAL id (e.g. "ism-principle-gov-01") or label (e.g. "GOV-01").',
      ),
    version: z.string().optional(),
    format: z.enum(["json", "markdown"]).optional(),
  },

• src/index.ts:84-91 (helper)

  Helper used by get_control to match a control by OSCAL id or human label (case-insensitive).

  function findControlMatch(flat: FlatControl[], controlId: string): FlatControl | undefined {
    const needle = controlId.toLowerCase();
    return (
      flat.find((c) => c.id.toLowerCase() === needle) ??
      flat.find((c) => c.label.toLowerCase() === needle) ??
      flat.find((c) => c.id.toLowerCase().endsWith(needle))
    );
  }

• src/store.ts:233-253 (helper)

  Renders a FlatControl as Markdown, used by get_control when format is 'markdown'.

  export function controlToMarkdown(c: FlatControl, version: string): string {
    const lines: string[] = [];
    lines.push(`# ${c.label} — ${c.title}`);
    lines.push("");
    lines.push(`- **Control ID:** \`${c.id}\``);
    lines.push(`- **ISM version:** ${version}`);
    if (c.groupPath.length > 0) {
      lines.push(`- **Section:** ${c.groupPath.join(" › ")}`);
    }
    if (c.applicability.length > 0) {
      lines.push(`- **Applicability:** ${c.applicability.join(", ")}`);
    }
    lines.push("");
    if (c.statement) {
      lines.push("## Statement");
      lines.push("");
      lines.push(c.statement);
      lines.push("");
    }
    return lines.join("\n");
  }