What causes "%s" in ipfs/kubo?

Fix the underlying cause reported by the message (usually an invalid or unresolvable CID input)

%s

Error message

%s

What it means

The text encoder for `ipfs cid inspect` re-raises the remote/processing error stored in CidInspectRes.ErrorMsg as the command's error. The message content is whatever the inspect operation put into ErrorMsg, so this is a pass-through of the underlying failure to the CLI user.

Source

Thrown at core/commands/cid.go:539

		// CIDv1: use base36 for libp2p-key, base32 for everything else
		v1 := cid.NewCidV1(c.Type(), c.Hash())
		v1Base := mbase.Encoding(mbase.Base32)
		if c.Type() == uint64(mc.Libp2pKey) {
			v1Base = mbase.Base36
		}
		v1Str, err := v1.StringOfBase(v1Base)
		if err != nil {
			v1Str = v1.String()
		}
		res.CidV1 = v1Str

		return cmds.EmitOnce(resp, res)
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, res *CidInspectRes) error {
			if res.ErrorMsg != "" {
				return fmt.Errorf("%s", res.ErrorMsg)
			}

			implicit := ""
			if res.Version == 0 {
				implicit = ", implicit"
			}

			fmt.Fprintf(w, "CID:        %s\n", res.Cid)
			fmt.Fprintf(w, "Version:    %d\n", res.Version)
			if res.Version == 0 {
				fmt.Fprintf(w, "Multibase:  %s (implicit)\n", res.Multibase.Name)
			} else {
				fmt.Fprintf(w, "Multibase:  %s (%s)\n", res.Multibase.Name, res.Multibase.Prefix)
			}
			fmt.Fprintf(w, "Multicodec: %s (0x%x%s)\n", res.Multicodec.Name, res.Multicodec.Code, implicit)
			fmt.Fprintf(w, "Multihash:  %s (0x%x%s)\n", res.Multihash.Name, res.Multihash.Code, implicit)
			fmt.Fprintf(w, "  Length:   %d bytes\n", res.Multihash.Length)
			fmt.Fprintf(w, "  Digest:   %s\n", res.Multihash.Digest)

View on GitHub (pinned to 329838acdf)

Solutions

Fix the underlying cause reported by the message (usually an invalid or unresolvable CID input)
Re-run with JSON output (`--enc=json`) to see the full structured result including res.ErrorMsg
Validate the CID with `ipfs cid format --format=%s <cid>` or a client-side cid.Decode before inspecting

Defensive patterns

Strategy: try-catch

Try / catch

err := cmd.Run()
if err != nil {
    var ee *cmds.Error
    if errors.As(err, &ee) {
        // inspect ee.Message (the original ErrorMsg) and handle
    }
}

Prevention

Use --enc=json to get structured error info instead of the text re-raise
Validate the CID input before running inspect
Read the res.ErrorMsg content; it names the true underlying cause

When it happens

Trigger: Running `ipfs cid inspect` (text output) when the underlying inspection failed and set res.ErrorMsg; the encoder then returns that message as an error.

Common situations: Inspecting a malformed or unresolvable CID string; daemon-side failure during inspection surfaced through the text encoder path.

Related errors

AI-assisted analysis of ipfs/kubo@329838acdf (2026-09-03). Data as JSON: /api/errors/32a0f5d1d1a4c1ef. Report an issue: GitHub.