conductor-oss/conductor · error · IllegalArgumentException

Skill package exceeds max uncompressed size of {maxUncompres

Error message

Skill package exceeds max uncompressed size of {maxUncompressedBytes} bytes

What it means

Thrown by parseSkillPackage when the cumulative uncompressed size across all entries exceeds maxUncompressedBytes (default 209,715,200 = 200 MiB, configurable via agentspan.skills.max-uncompressed-bytes). This is the zip-bomb defense: it sums bytes during streaming decompression and aborts when the total crosses the cap, regardless of how small the compressed input is.

Source

Thrown at agentspan/src/main/java/org/conductoross/conductor/ai/agentspan/runtime/service/SkillRegistryService.java:460

                    throw new IllegalArgumentException(
                            "Skill package contains duplicate path: " + path);
                }
                MessageDigest digest = MessageDigest.getInstance("SHA-256");
                long size = 0;
                ByteArrayOutputStream content = new ByteArrayOutputStream();
                byte[] buffer = new byte[8192];
                int read;
                while ((read = zip.read(buffer)) >= 0) {
                    digest.update(buffer, 0, read);
                    content.write(buffer, 0, read);
                    size += read;
                    totalUncompressedBytes += read;
                    if (size > maxPackageBytes) {
                        throw new IllegalArgumentException(
                                "Skill package contains oversized file: " + path);
                    }
                    if (totalUncompressedBytes > maxUncompressedBytes) {
                        throw new IllegalArgumentException(
                                "Skill package exceeds max uncompressed size of "
                                        + maxUncompressedBytes
                                        + " bytes");
                    }
                }
                contentByPath.put(path, content.toByteArray());
                files.add(
                        SkillFileEntry.builder()
                                .path(path)
                                .size(size)
                                .sha256(hex(digest.digest()))
                                .contentType(contentType(path))
                                .build());
            }
        } catch (IllegalArgumentException e) {
            throw e;
        } catch (Exception e) {
            throw new IllegalArgumentException("Invalid skill package zip: " + e.getMessage(), e);

View on GitHub (pinned to cf7c3e4a8a)

Solutions

1. Reduce the total uncompressed content of the package below the limit.
2. Raise agentspan.skills.max-uncompressed-bytes if the large total is intentional and trusted.
3. Scan uploaded packages for zip bombs before they reach this service if untrusted uploads are accepted.

Example fix

# application.yml
agentspan:
  skills:
    max-uncompressed-bytes: 524288000  # 500 MiB

// Before zipping, sum uncompressed sizes of all included files
long total = includedFiles.stream().mapToLong(p -> { try { return Files.size(p); } catch (IOException e) { return 0; } }).sum();
if (total > maxUncompressedBytes) throw new IllegalArgumentException("uncompressed total too large: " + total);

static boolean withinUncompressedTotal(long total, long maxUncompressedBytes) { return total <= maxUncompressedBytes; }

try { skillRegistryService.register(manifest, pkg); }
catch (IllegalArgumentException e) {
    if (e.getMessage().contains("max uncompressed size")) { /* reduce content or raise limit */ }
    else throw e;
}

When it happens

Trigger: POST /api/skills/register with a zip bomb — a tiny compressed file that decompresses to hundreds of MiB — or a legitimately large package whose combined uncompressed content exceeds 200 MiB. Checked incrementally so it trips mid-decompression.

Common situations: An adversarial or accidentally nested zip; bundling many large assets; lowering max-uncompressed-bytes in a shared config; vendoring a large dependency tree uncompressed.

Related errors

• Skill package exceeds max file count of {maxFileCount}
• Skill package contains oversized file: {path}
• Skill file is too large to preview: {cleanPath}
• Failed to read skill file: {e.getMessage()}
• Skill package exceeds max size of {maxPackageBytes} bytes

AI-assisted analysis of conductor-oss/conductor@cf7c3e4a8a (2026-08-14). Data as JSON: /api/errors/86c2ffe8f8ec9000. Report an issue: GitHub.