no version specified for tool {tool}\nuse `mise shell {tool}

Error message

no version specified for tool {tool}\nuse `mise shell {tool}@VERSION` to set a version

What it means

`mise shell` sets per-session tool versions by exporting env vars like MISE_NODE_VERSION via the activate hook; each TOOL argument must be TOOL@VERSION because the whole point is pinning a concrete version in the current session. The loop over self.tool bails on the first ToolArg whose tvr (tool version request) is None — unless --unset was given, which is checked first. The command also requires an activated session and a detectable shell before reaching this check.

Source

Thrown at src/cli/shell.rs:62

            err_inactive()?;
        }

        let shell = require_shell(
            None,
            &format!("Re-run `mise activate {EXAMPLE_SHELL}` in your shell rc file."),
        )?;

        if self.unset {
            for ta in &self.tool {
                let op = shell.unset_env(&tool_env_var_name(&ta.ba.short));
                print!("{op}");
            }
            return Ok(());
        }

        for ta in &self.tool {
            if ta.tvr.is_none() {
                bail!(
                    "no version specified for tool {tool}\nuse `mise shell {tool}@VERSION` to set a version",
                    tool = ta.ba.short,
                );
            }
        }

        let mut ts = ToolsetBuilder::new()
            .with_args(&self.tool)
            .build(&config)
            .await?;
        let opts = InstallOptions {
            force: false,
            jobs: self.jobs,
            raw: self.raw,
            ..Default::default()
        };
        let (_, missing) = ts.install_missing_versions(&mut config, &opts).await?;
        ts.notify_missing_versions(missing);

View on GitHub (pinned to 6f52dcdf99)

Solutions

Include the version exactly as the message hints: `mise shell node@22`
To remove a session pin instead, use the unset form: `mise shell --unset node`
For a persistent per-project version, use `mise use node@22` (writes config) rather than `mise shell`

Example fix

# before
mise shell node   # no version specified for tool node; use `mise shell node@VERSION`

# after
mise shell node@22
# to clear it later:
mise shell -u node

Defensive patterns

Strategy: validation

Validate before calling

# require TOOL@VERSION before calling mise shell
for t in "$@"; do
  case "$t" in
    *@*) ;;
    *) echo "usage: mise shell TOOL@VERSION (got: $t)" >&2; exit 2;;
  esac
done
mise shell "$@"

Type guard

has_version_spec() { case "$1" in *@*) return 0;; *) return 1;; esac; }

Try / catch

Catch 'no version specified', append @<version> to the offending tool (named in the message), and rerun once; if the intent was clearing the pin, rerun with `mise shell -u <tool>`.

Prevention

Remember `mise shell` always pins: TOOL@VERSION, no exceptions except --unset
Use `mise use` for persistent versions and `mise shell` for session pins
Guard wrapper scripts with a TOOL@* pattern check

When it happens

Trigger: Running `mise shell node` (no @VERSION) inside an activated session; passing a bare tool name when intending to pin a version; note `mise shell -u node` (unset) is the valid form without a version.

Common situations: Muscle memory from `mise use node`-style commands; forgetting the @ syntax in shell rc snippets or docs copied from `mise use` examples; scripting session setup quickly.

Related errors

AI-assisted analysis of jdx/mise@6f52dcdf99 (2026-08-22). Data as JSON: /api/errors/33373bd078688d92. Report an issue: GitHub.