Aider config uses inline/scalar read; use block-list form…

Error message

Aider config uses inline/scalar read; use block-list form before enabling Caveman

What it means

aiderNativeConfig() can only append the Caveman core path to a `read:` key that uses YAML block-list form (`read:` with nothing or a comment after the colon). If the config uses an inline/scalar form such as `read: foo.md`, the installer cannot safely splice entries and asks the user to convert it to block-list form first.

Solutions

Convert the inline/scalar `read:` to block-list form in ~/.aider.conf.yml (one `- path` item per line, indented).
Re-run the Caveman enable command after the conversion.
If a list of files exists inline, expand each element into its own `- ` line under `read:`.

Example fix

// before
read: instructions.md
// after
read:
  - instructions.md

Defensive patterns

Strategy: validation

Validate before calling

const lines = readFileSync(aiderCfg, 'utf8').split('\n');
const idx = lines.findIndex((l) => /^read\s*:/.test(l));
if (idx !== -1 && !/^read\s*:\s*(?:#.*)?$/.test(lines[idx])) {
  // convert `read: value` to block-list form before enabling
}

Try / catch

try {
  await cavemanEnableAider();
} catch (e) {
  if (String(e.message).includes('inline/scalar read')) {
    convertReadToBlockList(aiderCfg);
    await cavemanEnableAider();
  }
}

Prevention

Always use block-list form for `read:` in ~/.aider.conf.yml.
Avoid `read: file.md` scalar shorthand; write `- file.md` under `read:`.
Expand inline arrays (`read: [a, b]`) into block lists.
Check the Caveman Aider docs for the expected config shape before enabling.

When it happens

Trigger: Enabling Caveman for Aider when ~/.aider.conf.yml contains exactly one `read:` line but it has an inline value, e.g. `read: instructions.md` or `read: [a.md, b.md]`.

Common situations: Users who wrote a compact one-line read config; older Aider examples/docs showing scalar `read:`; configs converted from other tools' formats that use inline lists.

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/c5720ccb7abe5ec7. Report an issue: GitHub.

Appendix: source

Thrown at packages/cli/src/index.ts:7431

  const lines = source.replace(/\r\n/g, "\n").split("\n");
  const routeIndexes = lines.flatMap((line, index) => /^openai-api-base\s*:/.test(line) ? [index] : []);
  if (routeIndexes.length > 1) throw new Error("Aider config has duplicate openai-api-base keys; refusing unsafe merge");
  const routeBlockLines = [AIDER_NATIVE_ROUTE_BEGIN, `openai-api-base: ${yamlQuote(route)}`, AIDER_NATIVE_ROUTE_END];
  const routeBlock = routeBlockLines.join(newline);
  const previousRouteLine = routeIndexes.length === 1 ? lines[routeIndexes[0]!]! : null;
  if (routeIndexes.length === 1) lines.splice(routeIndexes[0]!, 1, ...routeBlockLines);
  else {
    if (lines.some((line) => line.trim() !== "") && lines[lines.length - 1]?.trim()) lines.push("");
    lines.push(...routeBlockLines);
  }

  const readIndexes = lines.flatMap((line, index) => /^read\s*:/.test(line) ? [index] : []);
  if (readIndexes.length > 1) throw new Error("Aider config has duplicate read keys; refusing unsafe merge");
  let readBlockLines: string[];
  if (readIndexes.length === 1) {
    const readIndex = readIndexes[0]!;
    if (!/^read\s*:\s*(?:#.*)?$/.test(lines[readIndex]!)) {
      throw new Error("Aider config uses inline/scalar read; use block-list form before enabling Caveman");
    }
    let end = readIndex + 1;
    while (end < lines.length && !/^[A-Za-z0-9][A-Za-z0-9_-]*\s*:/.test(lines[end]!)) end++;
    readBlockLines = [`  ${AIDER_NATIVE_READ_BEGIN}`, `  - ${yamlQuote(corePath)}`, `  ${AIDER_NATIVE_READ_END}`];
    lines.splice(end, 0, ...readBlockLines);
  } else {
    if (lines.some((line) => line.trim() !== "") && lines[lines.length - 1]?.trim()) lines.push("");
    readBlockLines = [AIDER_NATIVE_READ_BEGIN, "read:", `  - ${yamlQuote(corePath)}`, AIDER_NATIVE_READ_END];
    lines.push(...readBlockLines);
  }
  const readBlock = readBlockLines.join(newline);
  const text = lines.join(newline).replace(/(?:\r?\n)+$/, "") + newline;
  return { text, routeBlock, previousRouteLine, readBlock };
}

function aiderNativeMutations(gw: string): NativeMutation[] {
  const configPath = join(homedir(), ".aider.conf.yml");
  const configBefore = fileBytes(configPath);

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