Mintplex-Labs/anything-llm · warning

Key is required

Error message

Key is required

What it means

_checkVariableKey is the shared validator for system-prompt variable keys used by create and update. It throws 'Key is required' when the key argument is falsy - undefined, null, or empty string. In practice the request payload or function call omitted the key field entirely.

Solutions

1. Include a non-empty `key` in the request payload or function call
2. Validate payload shape at the API boundary before invoking the model
3. If the key comes from user input, require it in form/UI validation before submit

Example fix

// before
await SystemPromptVariables.create({ value: 'abc', description: 'd' }); // throws: Key is required

// after
await SystemPromptVariables.create({ key: 'my_key', value: 'abc', description: 'd' });

function hasKey(payload) {
  return typeof payload?.key === 'string' && payload.key.length > 0;
}

if (!hasKey(req.body)) {
  return res.status(400).json({ error: 'key is required' });
}

const hasValidKeyShape = (p) =>
  p !== null && typeof p === 'object' && typeof p.key === 'string' && p.key.length > 0;

try {
  await SystemPromptVariables.create(payload);
} catch (err) {
  if (err.message === 'Key is required') {
    return res.status(400).json({ error: 'Provide a key field' });
  }
  throw err;
}

When it happens

Trigger: POST/PUT to system-prompt-variables without a `key` field in the body; calling SystemPromptVariables.create({ value, description }) with key missing; key set to empty string ''.

Common situations: Form submissions that only mark optional fields; API clients built from a partial example; destructuring payload with a renamed property so key ends up undefined.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Device OS and name are required
• Key cannot start with 'system.'
• Key cannot start with 'user.'
• Key must be a string
• Key must be at least 3 characters

AI-assisted analysis of Mintplex-Labs/anything-llm@3aec848f28 (2026-08-18). Data as JSON: /api/errors/29e05bc072936a42. Report an issue: GitHub.

Appendix: source

Thrown at server/models/systemPromptVariables.js:357

        } else {
          result = result.replace(match, variable.value || match);
        }
      }
      return result;
    } catch (error) {
      console.error("Error in expandSystemPromptVariables:", error);
      return str;
    }
  },

  /**
   * Internal function to check if a variable key is valid
   * @param {string} key
   * @param {boolean} checkExisting
   * @returns {Promise<boolean>}
   */
  _checkVariableKey: async function (key = null, checkExisting = true) {
    if (!key) throw new Error("Key is required");
    if (typeof key !== "string") throw new Error("Key must be a string");
    if (!/^[a-zA-Z0-9_]+$/.test(key))
      throw new Error("Key must contain only letters, numbers and underscores");
    if (key.length > 255)
      throw new Error("Key must be less than 255 characters");
    if (key.length < 3) throw new Error("Key must be at least 3 characters");
    if (key.startsWith("user."))
      throw new Error("Key cannot start with 'user.'");
    if (key.startsWith("system."))
      throw new Error("Key cannot start with 'system.'");
    if (checkExisting && (await this.get(key)) !== null)
      throw new Error("System prompt variable with this key already exists");

    return true;
  },
};

module.exports = { SystemPromptVariables };

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