What causes "reading stdin: %w" in chenhg5/cc-connect?

Ensure the producer actually writes and closes successfully: `echo "msg" | cc-connect send --stdin`.

reading stdin: %w

Error message

reading stdin: %w

What it means

When `cc-connect send --stdin` is used, parseSendArgs reads the whole of os.Stdin with io.ReadAll and wraps any read failure as "reading stdin: %w". This indicates the OS-level read of the standard input stream failed, not an empty or malformed message.

Source

Thrown at cmd/cc-connect/send.go:168

		case "--at-all":
			req.AtAll = true
		case "--data-dir":
			if i+1 >= len(args) {
				return req, "", fmt.Errorf("--data-dir requires a value")
			}
			i++
			dataDir = args[i]
		case "--help", "-h":
			return req, "", errSendUsage
		default:
			positional = append(positional, args[i])
		}
	}

	if useStdin {
		data, err := io.ReadAll(os.Stdin)
		if err != nil {
			return req, "", fmt.Errorf("reading stdin: %w", err)
		}
		req.Message = strings.TrimSpace(string(data))
	}
	if req.Project == "" {
		req.Project = strings.TrimSpace(os.Getenv("CC_PROJECT"))
	}
	if req.SessionKey == "" {
		req.SessionKey = strings.TrimSpace(os.Getenv("CC_SESSION_KEY"))
	}
	if req.Message == "" {
		req.Message = strings.Join(positional, " ")
	}

	maxAtt := resolveMaxAttachmentSize(loadSendConfigBestEffort())

	images, err := loadImageAttachments(imagePaths, maxAtt)
	if err != nil {
		return req, "", err

View on GitHub (pinned to 4000b2338a)

Solutions

Ensure the producer actually writes and closes successfully: `echo "msg" | cc-connect send --stdin`.
Check the upstream command's exit status; fix its own I/O error first.
Avoid redirecting stdin from a directory or other non-readable file; use `< /dev/null` only when not passing --stdin.
Pass the message as an argument instead of --stdin if stdin is unreliable in your environment.

Example fix

// before
some_flaky_cmd | cc-connect send --stdin
// after
msg=$(some_cmd) && printf '%s' "$msg" | cc-connect send --stdin

Defensive patterns

Strategy: try-catch

Validate before calling

# check upstream succeeds before piping
set -o pipefail
producer_cmd | cc-connect send --stdin

Try / catch

out, err := cmd.CombinedOutput()
if err != nil && strings.Contains(string(out), "reading stdin:") {
    log.Printf("stdin read failed, check producer: %v", err)
}

Prevention

Use set -o pipefail to surface upstream pipe errors.
Redirect from /dev/null explicitly when there is no input (and don't pass --stdin).
Avoid piping from directories or special files.
Prefer --message when stdin is unreliable in your environment.

When it happens

Trigger: `cc-connect send --stdin` where stdin is a closed/invalid descriptor, a pipe whose writer exited with an I/O error, or stdin redirected from an unreadable file.

Common situations: CI job where the upstream pipe was closed early; running under a supervisor that detached fds; piping from a command that itself failed; redirecting stdin from a directory or special file.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/f523fee9d0f70083. Report an issue: GitHub.