github/github-mcp-server · error

failed to read file content: %w

Error message

failed to read file content: %w

What it means

Thrown by the repo:// resource read handler (pkg/github/repository_resource.go) after GitHub's raw content endpoint already returned HTTP 200: io.ReadAll failed while streaming the body. The wrapped error is almost always a transport failure (connection reset, unexpected EOF, deadline exceeded) that hit mid-download, after status and headers were received. The file exists and is reachable; only the body transfer did not complete.

Source

Thrown at pkg/github/repository_resource.go:213

			return nil, fmt.Errorf("failed to get raw content: %w", err)
		}
		defer func() {
			_ = resp.Body.Close()
		}()
		// If the raw content is not found, we will fall back to the GitHub API (in case it is a directory)
		switch {
		case resp.StatusCode == http.StatusOK:
			ext := filepath.Ext(path)
			mimeType := resp.Header.Get("Content-Type")
			if ext == ".md" {
				mimeType = "text/markdown"
			} else if mimeType == "" {
				mimeType = mime.TypeByExtension(ext)
			}

			content, err := io.ReadAll(resp.Body)
			if err != nil {
				return nil, fmt.Errorf("failed to read file content: %w", err)
			}

			switch {
			case strings.HasPrefix(mimeType, "text"), strings.HasPrefix(mimeType, "application"):
				return &mcp.ReadResourceResult{
					Contents: []*mcp.ResourceContents{
						{
							URI:      request.Params.URI,
							MIMEType: mimeType,
							Text:     string(content),
						},
					},
				}, nil
			default:
				var buf bytes.Buffer
				base64Encoder := base64.NewEncoder(base64.StdEncoding, &buf)
				_, err := base64Encoder.Write(content)
				if err != nil {

View on GitHub (pinned to 0ea1f775a7)

Solutions

1. Retry the read_resource call once - mid-body interruptions are usually transient and succeed on a second attempt
2. Check the file size first (e.g. via get_file_contents metadata) and avoid streaming files above your reliability limit
3. Raise the raw client's HTTP timeout or pass a context with a longer deadline when reading large files
4. If it reproduces only on one network, inspect proxy/firewall treatment of raw.githubusercontent.com

Example fix

// before
content, err := io.ReadAll(resp.Body)
if err != nil {
    return nil, fmt.Errorf("failed to read file content: %w", err)
}
// after - bound the read and signal transiency to callers
const maxRawBytes = 64 << 20
content, err := io.ReadAll(io.LimitReader(resp.Body, maxRawBytes))
if err != nil {
    return nil, fmt.Errorf("failed to read file content (transfer interrupted, likely transient): %w", err)
}

// Before read_resource on a repo:// URI, confirm the blob is small enough to stream reliably
meta, _, err := client.Repositories.GetContents(ctx, owner, repo, path, nil)
if err == nil && meta != nil && meta.GetSize() > 50<<20 {
    return fmt.Errorf("file %s is %d bytes; fetch it with git instead of read_resource", path, meta.GetSize())
}

func isTransientBodyErr(err error) bool {
	var netErr net.Error
	if errors.As(err, &netErr) {
		return true
	}
	return errors.Is(err, io.ErrUnexpectedEOF) ||
		errors.Is(err, syscall.ECONNRESET) ||
		strings.Contains(err.Error(), "http2: stream closed")
}

var result *mcp.ReadResourceResult
err := retry(ctx, 3, 500*time.Millisecond, func() error {
    var e error
    result, e = readResource(ctx, repoURI)
    if e != nil && isTransientBodyErr(e) {
        return e // retryable
    }
    return nil
})
if err != nil {
    return fmt.Errorf("raw file read failed after retries: %w", err)
}

When it happens

Trigger: Reading a repo://raw/... resource URI when the connection drops between headers and the last body byte: rawClient.GetRawContent returned 200, then a proxy or raw.githubusercontent.com reset the stream, the client context deadline expired during a large file, or the TLS connection broke mid-transfer.

Common situations: Reading very large files (hundreds of MB) through read_resource; aggressive HTTP client timeouts on the raw client; corporate proxies that cut long transfers; flaky CI or mobile networks.

Related errors

• failed to read response body: %w
• failed to read response body: %w
• failed to fetch raw content: %s
• failed to read response body: %w
• failed to read response body: %w

AI-assisted analysis of github/github-mcp-server@0ea1f775a7 (2026-08-15). Data as JSON: /api/errors/09e81f7ae6c489cd. Report an issue: GitHub.