github/copilot-sdk · error

creating runtime asset directory

Error message

creating runtime asset directory: %w

What it means

After reading a runtime asset from the tar archive, installRuntimeAssets creates the parent directories for its destination path with os.MkdirAll(dir, 0755). This error wraps a failure of that MkdirAll call, i.e. the asset's target directory could not be created.

Solutions

1. Check permissions on installDir and its parents; run the install with sufficient privileges (elevate or chown the target directory).
2. Ensure installDir is on a writable filesystem and no regular file occupies a path that must be a directory.
3. Choose a user-writable installDir instead of a system location.

Example fix

// before
client.InstallAt("/usr/local/lib/mycli")
// after
client.InstallAt(filepath.Join(os.Getenv("HOME"), ".local/lib/mycli"))

func canWriteDir(dir string) error {
    probe := filepath.Join(dir, ".write-probe")
    if err := os.MkdirAll(dir, 0o755); err != nil {
        return err
    }
    f, err := os.Create(probe)
    if err != nil {
        return err
    }
    f.Close()
    return os.Remove(probe)
}

if err := client.InstallAt(dir); err != nil {
    if strings.Contains(err.Error(), "creating runtime asset directory") {
        // surface a friendly 'check permissions on <dir>' message
    }
}

When it happens

Trigger: os.MkdirAll(filepath.Dir(path), 0755) fails while extracting any entry during installAt or installRuntimeAt — typically a permission problem on installDir or a component of the path.

Common situations: Installing into a directory the current user cannot write (e.g. /usr/local or Program Files without elevation), installDir pointing at a read-only filesystem, or a file existing where a directory is needed.

Understand the failure class

Background: mkdir permission denied (EACCES): failed to create directory errors explained — this error's family across 32 libraries.

Related errors

• Published runtime wrapper is not a non-empty executable…
• Failed to make Copilot CLI executable:
• failed to create output directory
• failed to chmod binary
• creating install directory

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/9ec4d439345506da. Report an issue: GitHub.

Appendix: source

Thrown at go/internal/embeddedcli/embeddedcli.go:405

			break
		}
		if err != nil {
			return fmt.Errorf("reading runtime assets: %w", err)
		}
		if header.Typeflag != tar.TypeReg {
			continue
		}
		clean := filepath.Clean(filepath.FromSlash(header.Name))
		if !filepath.IsLocal(clean) {
			return fmt.Errorf("unsafe runtime asset path %q", header.Name)
		}
		content, err := io.ReadAll(tarReader)
		if err != nil {
			return fmt.Errorf("reading runtime asset %q: %w", header.Name, err)
		}
		path := filepath.Join(installDir, clean)
		if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
			return fmt.Errorf("creating runtime asset directory: %w", err)
		}
		hash := sha256.Sum256(content)
		mode := os.FileMode(header.Mode & 0777)
		if err := installVerifiedFile(path, bytes.NewReader(content), hash[:], mode, "runtime asset"); err != nil {
			return err
		}
	}
	runtimeAssetsInstalled = true
	return nil
}

func validateRuntimePairConfig(wrapper io.Reader, wrapperHash []byte, node io.Reader, nodeHash []byte, prefix string) {
	if (wrapper == nil) != (node == nil) {
		panic(prefix + "RuntimeExecutable and " + prefix + "RuntimeNode must be provided together")
	}
	if wrapper == nil {
		return
	}

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