zed-industries/zed · error

no marker tags found in output

Error message

no marker tags found in output

What it means

apply_marker_span_impl found zero parsed marker tags in the model output, so there is no span to reconstruct. The output simply did not contain any recognizable marker-tag syntax (wrong format, empty, or a refusal/ prose answer).

Source

Thrown at crates/zeta_prompt/src/multi_region.rs:753

        cursor_marker,
        &marker_offsets,
        |i| marker_tag(i + 1),
    );
}

/// Parse byte-exact model output and reconstruct the full new editable region.
///
/// `resolve_boundary` maps a parsed tag value to an absolute byte offset in
/// old_editable, given the marker_offsets. Returns `(start_byte, end_byte)` or
/// an error.
fn apply_marker_span_impl(
    old_editable: &str,
    tags: &[ParsedTag],
    output: &str,
    resolve_boundaries: impl Fn(isize, isize) -> Result<(usize, usize)>,
) -> Result<String> {
    if tags.is_empty() {
        return Err(anyhow!("no marker tags found in output"));
    }
    if tags.len() == 1 {
        return Err(anyhow!(
            "only one marker tag found in output, expected at least two"
        ));
    }

    let start_value = tags[0].value;
    let end_value = tags[tags.len() - 1].value;

    if start_value == end_value {
        return Ok(old_editable.to_string());
    }

    let (start_byte, end_byte) = resolve_boundaries(start_value, end_value)?;

    if start_byte > end_byte {
        return Err(anyhow!("start marker must come before end marker"));

View on GitHub (pinned to f4178619ac)

Solutions

1. Check that the model output uses the expected marker-tag format for the configured Zeta format version
2. Treat as a no-op or rejection and re-prompt the model for correctly formatted output
3. Strip any wrapper text/decoration from the output before parsing tags

When it happens

Trigger: Thrown at crates/zeta_prompt/src/multi_region.rs:753 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/51a27f84bdf6a641. Report an issue: GitHub.