Description

specify workflow run/resume --json is contracted to emit a single JSON object on stdout (the module already goes to great lengths for this — see _emit_workflow_json and _stdout_to_stderr_when, which dup2-redirects step output to stderr during execution). But the command's own error paths use console.print, which writes to stdout even under --json:

except FileNotFoundError:
    console.print(f"[red]Error:[/red] Workflow not found: {source}")   # -> stdout
...
console.print("[red]Workflow validation failed:[/red]")               # -> stdout

So a not-found / invalid / validation-failed / failed run — and the shared _parse_input_values invalid-input error — all corrupt the JSON stream a caller is trying to parse.

Fix

Route those error messages through err_console when --json is set (a no-op in normal text mode, where they stay on the regular console). This mirrors the stderr-only error routing already used by specify bundle (_fail) and by err_console elsewhere in this same module. Covers both workflow run and workflow resume plus the shared input parser.

Testing

New TestWorkflowRunJsonErrorStream (CliRunner separates stdout/stderr in this repo's Click):

• validation-failure under --json: "validation failed" is not on stdout and is on stderr;
• invalid --input under --json: "Invalid input format" is not on stdout and is on stderr.

Both fail-before / pass-after (verified by source-stash). uvx ruff check clean.

AI Disclosure

• I did use AI assistance (describe below)

Found and fixed with Claude Code (Claude Fable 5) under my direction. AI spotted that the error paths bypassed the module's own stdout-cleanliness machinery; I confirmed the stream corruption, verified fail-before/pass-after, and reviewed the diff.