What causes "Failed to read skill package: {e.getMessage()}" in conductor-oss/conductor?

Check server disk space in the multipart temp location (spring.servlet.multipart.location).

conductor-oss/conductor · error · IllegalArgumentException

Failed to read skill package: {e.getMessage()}

Error message

Failed to read skill package: {e.getMessage()}

What it means

Thrown by register() (via readPackage) when packageFile.getBytes() throws an IOException. This is an I/O failure reading the uploaded multipart file's bytes from its temporary storage, not a content error. The original IOException is attached as the cause.

Source

Thrown at agentspan/src/main/java/org/conductoross/conductor/ai/agentspan/runtime/service/SkillRegistryService.java:420

            throw new IllegalArgumentException("Skill manifest is required");
        }
        try {
            return MAPPER.readValue(manifestJson, MAP_TYPE);
        } catch (IOException e) {
            throw new IllegalArgumentException("Invalid skill manifest JSON: " + e.getMessage(), e);
        }
    }

    private byte[] readPackage(MultipartFile packageFile) {
        try {
            byte[] bytes = packageFile.getBytes();
            if (bytes.length > maxPackageBytes) {
                throw new IllegalArgumentException(
                        "Skill package exceeds max size of " + maxPackageBytes + " bytes");
            }
            return bytes;
        } catch (IOException e) {
            throw new IllegalArgumentException(
                    "Failed to read skill package: " + e.getMessage(), e);
        }
    }

    @SuppressWarnings("unchecked")
    private ParsedSkillPackage parseSkillPackage(byte[] bytes, Map<String, Object> manifest) {
        List<SkillFileEntry> files = new ArrayList<>();
        Map<String, byte[]> contentByPath = new TreeMap<>();
        long totalUncompressedBytes = 0;
        try (ZipInputStream zip = new ZipInputStream(new ByteArrayInputStream(bytes))) {
            ZipEntry entry;
            while ((entry = zip.getNextEntry()) != null) {
                if (entry.isDirectory()) {
                    continue;
                }
                if (files.size() >= maxFileCount) {
                    throw new IllegalArgumentException(
                            "Skill package exceeds max file count of " + maxFileCount);

View on GitHub (pinned to cf7c3e4a8a)

Solutions

Check server disk space in the multipart temp location (spring.servlet.multipart.location).
Increase client upload timeout and retry the upload.
Inspect the caused-by IOException for the specific I/O error (No space left, file not found, etc.).

Example fix

// no code fix — operational recovery
# ensure temp dir has space and retry the upload
df -h /tmp
POST /api/skills/register (retry)

Defensive patterns

Strategy: retry

Try / catch

try { skillRegistryService.register(manifest, pkg); }
catch (IllegalArgumentException e) {
    if (e.getMessage().startsWith("Failed to read skill package")) {
        // check temp-dir disk space, then retry the upload
    } else throw e;
}

Prevention

Ensure the multipart temp directory has adequate free space and is writable.
Use a stable client upload timeout to avoid partial temp files.

When it happens

Trigger: POST /api/skills/register where Spring's multipart temp file was deleted mid-request, the temp dir is full or unwritable, or the client disconnected during upload leaving a partial temp file.

Common situations: Low disk space in the multipart temp directory; a reverse proxy timing out and closing the connection; container ephemeral storage exhaustion; the temp file cleaned up by another process during a slow upload.

Related errors

AI-assisted analysis of conductor-oss/conductor@cf7c3e4a8a (2026-08-14). Data as JSON: /api/errors/aa2ab64e9d64bb3c. Report an issue: GitHub.