JuliusBrussee/caveman · error · Error

assembly slot ${JSON.stringify(slot.id)} content is not JSON

Error message

assembly slot ${JSON.stringify(slot.id)} content is not JSON-serializable

What it means

Error "assembly slot ${JSON.stringify(slot.id)} content is not JSON-serializable" thrown in JuliusBrussee/caveman.

Source

Thrown at packages/sdk/typescript/src/index.ts:1825

  }

  const ids = new Set<string>();
  let ledger = assemblyHashLedgers.get(cave);
  if (!ledger) {
    ledger = new Map<string, string>();
    assemblyHashLedgers.set(cave, ledger);
  }
  const normalized = options.slots.map((slot) => {
    if (!slot.id || ids.has(slot.id)) throw new Error(`assembly slot id must be non-empty and unique: ${JSON.stringify(slot.id)}`);
    ids.add(slot.id);
    if (!["stable", "session", "volatile"].includes(slot.stability)) {
      throw new Error(`assembly slot ${JSON.stringify(slot.id)} has unknown stability ${JSON.stringify(slot.stability)}`);
    }
    let contentJSON: string;
    try {
      contentJSON = canonicalJSON(slot.content);
    } catch {
      throw new Error(`assembly slot ${JSON.stringify(slot.id)} content is not JSON-serializable`);
    }
    const contentHash = sha256Hex(contentJSON);
    if (slot.stability !== "volatile") {
      const key = `${options.sessionId}\0${slot.id}`;
      const previous = ledger.get(key);
      if (previous !== undefined && previous !== contentHash) throw new AssemblyStabilityError(slot.id);
      ledger.set(key, contentHash);
    }
    return { ...slot, content: JSON.parse(contentJSON) as unknown };
  });

  const ordered = (["stable", "session", "volatile"] as const)
    .flatMap((stability) => normalized.filter((slot) => slot.stability === stability));
  const prefixSlots = ordered.filter((slot) => slot.stability !== "volatile");
  const volatileSlots = ordered.filter((slot) => slot.stability === "volatile");

  let request: Record<string, unknown>;
  let prefixBytes: string;

View on GitHub (pinned to 27d5a3981a)

Solutions

1. Make the assembly slot content JSON-serializable.

When it happens

Trigger: Thrown at packages/sdk/typescript/src/index.ts:1825 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of JuliusBrussee/caveman@27d5a3981a (2026-08-15). Data as JSON: /api/errors/17f031f7eeccdecb. Report an issue: GitHub.