Hermes block changed after enable; refusing destructive…

Error message

Hermes ${key.replace("_block", "")} block changed after enable; refusing destructive disable

What it means

Alongside the routing block, Hermes disable also removes the journaled plugin_block and mcp_block if present. If a journaled block is not a string or is no longer found in the file, the tool throws with the block name (plugin/mcp) interpolated. Same protection principle: never delete text that no longer matches what was installed.

Solutions

Restore the plugin/mcp block to its exact journaled content, then re-run disable.
Manually delete both the Caveman blocks from the Hermes config and clear the journal entry.
Re-run enable to rewrite all blocks and refresh the journal, then disable.

Example fix

// before: mcp block edited after enable
plugins: [caveman, extra]  # modified
// after: exact journaled block restored
plugins: [caveman]

Defensive patterns

Strategy: validation

Validate before calling

const text = fs.readFileSync(hermesConfig, 'utf8');
for (const key of ['plugin_block', 'mcp_block']) {
  const block = journal.owned?.[key];
  if (block !== null && block !== undefined && (typeof block !== 'string' || !text.includes(block))) {
    throw new Error(`${key} drift detected; restore before disable`);
  }
}

Type guard

const optionalBlockIntact = (text, owned, key) => {
  const b = owned?.[key];
  return b == null || (typeof b === 'string' && text.includes(b));
};

Try / catch

try {
  await caveman.disable(['hermes']);
} catch (err) {
  const m = err.message.match(/Hermes (\w+) block changed/);
  if (m) console.error(`Restore the Hermes ${m[1]} block to its journaled form or delete it manually.`);
  else throw err;
}

Prevention

Keep the plugin and MCP snippets untouched between enable and disable.
Re-run Hermes manifest regeneration only after Caveman disable completes.
Commit the config before enable for easy diff/restore.
If one block was already edited, restore both blocks before retrying disable.

When it happens

Trigger: Running disable with kind === "hermes-config" when operation.owned[key] (key = plugin_block or mcp_block) is present but either not a string or not found via text.includes(block).

Common situations: User edited the embedded Caveman plugin registration or MCP snippet after enable; Hermes rewrote the manifest merging the snippet; partial manual uninstall removed one block but not the journal.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

AI-assisted analysis of JuliusBrussee/caveman@3ee70a1026 (2026-09-20). Data as JSON: /api/errors/d06ab257ebc04684. Report an issue: GitHub.

Appendix: source

Thrown at packages/cli/src/index.ts:8415

  if (operation.kind === "aider-core") {
    throw new Error(`${operation.file} changed after enable; refusing destructive disable`);
  }
  if (operation.kind === "hermes-plugin-manifest" || operation.kind === "hermes-plugin-init") {
    throw new Error(`${operation.file} changed after enable; refusing destructive disable`);
  }
  if (operation.kind === "hermes-config") {
    let text = current.toString("utf8");
    const routeBlock = operation.owned?.route_block;
    const previousRouteLines = operation.owned?.previous_route_lines;
    if (typeof routeBlock !== "string" || !Array.isArray(previousRouteLines)) {
      throw new Error("Hermes integration journal lacks owned routing block");
    }
    if (!text.includes(routeBlock)) throw new Error("Hermes routing block changed after enable; refusing destructive disable");
    text = text.replace(routeBlock, previousRouteLines.filter((line): line is string => typeof line === "string").join("\n"));
    for (const key of ["plugin_block", "mcp_block"] as const) {
      const block = operation.owned?.[key];
      if (block === null || block === undefined) continue;
      if (typeof block !== "string" || !text.includes(block)) throw new Error(`Hermes ${key.replace("_block", "")} block changed after enable; refusing destructive disable`);
      text = text.replace(block, "");
    }
    return Buffer.from(text);
  }
  const rootBlock = operation.owned?.root_block;
  const tablesBlock = operation.owned?.tables_block;
  if (typeof rootBlock !== "string" || typeof tablesBlock !== "string") throw new Error("Codex integration journal lacks owned blocks");
  let text = current.toString("utf8");
  for (const [block, begin] of [[rootBlock, CODEX_NATIVE_ROOT_BEGIN], [tablesBlock, CODEX_NATIVE_TABLES_BEGIN]] as const) {
    if (text.includes(begin) && !text.includes(block)) throw new Error("Codex Caveman config block changed after enable; refusing destructive disable");
    text = text.replace(`${block}\n\n`, "").replace(`\n\n${block}\n`, "\n").replace(block, "");
  }
  return Buffer.from(text);
}

function writeNativeRestoration(file: string, bytes: Buffer | null): void {
  if (bytes) {
    atomicWriteFile(file, bytes);

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