leviath_cli/commands/

auth.rs

//! `lev auth` - inspect and move the secrets Leviath holds.
//!
//! Leviath keeps two kinds of long-lived secret: provider API keys and MCP OAuth
//! grants. `[security] credential_store` decides whether they live in Leviath's
//! own `0600` files or in the OS credential store; this command reports which,
//! checks that the OS store is actually reachable, and moves secrets between the
//! two.

use crate::config::Config;
use clap::{Args, Subcommand};
use leviath_core::{CredentialStore, CredentialStoreKind};

/// Arguments for `lev auth`.
#[derive(Debug, Args)]
pub struct AuthArgs {
    #[command(subcommand)]
    command: AuthCommand,
}

#[derive(Debug, Subcommand)]
enum AuthCommand {
    /// Show which credential backend is in use and what it holds
    Status,

    /// Move stored secrets into the OS credential store
    ///
    /// Reads the keys currently in `~/.leviath/config.toml`, writes them to the
    /// OS store, and rewrites the config without them.
    Migrate {
        /// Move secrets back out of the OS store into `~/.leviath/config.toml`
        #[arg(long)]
        to_file: bool,

        /// Show what would move without changing anything
        #[arg(long)]
        dry_run: bool,
    },
}

impl AuthArgs {
    /// A `status` invocation, for routing tests in `dispatch`.
    #[cfg(test)]
    pub(crate) fn status_for_test() -> Self {
        Self {
            command: AuthCommand::Status,
        }
    }

    /// A `migrate` invocation, for driving the command end to end.
    #[cfg(test)]
    pub(crate) fn migrate_for_test(to_file: bool, dry_run: bool) -> Self {
        Self {
            command: AuthCommand::Migrate { to_file, dry_run },
        }
    }
}

/// Run `lev auth`.
pub async fn execute(args: AuthArgs) -> anyhow::Result<()> {
    let path = Config::config_path();
    match args.command {
        AuthCommand::Status => {
            let config = Config::load_from_path_public(&path)?;
            print!("{}", render_status(&status(&config, &path)));
            Ok(())
        }
        AuthCommand::Migrate { to_file, dry_run } => migrate(&path, to_file, dry_run),
    }
}

/// What `lev auth status` found, separated from how it is printed so the report
/// itself is testable.
#[derive(Debug, PartialEq)]
pub(crate) struct Status {
    /// The configured backend.
    pub kind: CredentialStoreKind,
    /// Whether this build was compiled with OS credential store support.
    pub supported: bool,
    /// `None` if the store is reachable, `Some(reason)` if it is not. Always
    /// `None` for the file backend, which needs no store.
    pub unavailable: Option<String>,
    /// Providers whose key is set, from any source.
    pub providers: Vec<String>,
    /// MCP servers with a stored OAuth grant.
    pub mcp_servers: Vec<String>,
    /// Providers whose key is present in *both* the config file and the OS
    /// store. A duplicate is not an error, but it is worth saying: the file
    /// copy wins, so rotating the keychain entry would appear to do nothing.
    pub duplicated: Vec<String>,
    /// The config file path, for the report.
    pub config_path: String,
}

/// Inspect the current credential situation.
pub(crate) fn status(config: &Config, path: &std::path::Path) -> Status {
    let resolved = crate::credentials::store_for(config.security.credential_store);
    status_with(config, path, resolved)
}

/// Core of [`status`] with the backend already resolved.
///
/// The resolution is the caller's because "this machine has no credential
/// store" cannot be produced in a test by *not installing* one: the real probe
/// would install the platform store and read the developer's actual login
/// keychain. Passing the outcome in is what makes the unavailable case testable.
pub(crate) fn status_with(
    config: &Config,
    path: &std::path::Path,
    resolved: crate::credentials::Resolved,
) -> Status {
    let kind = config.security.credential_store;
    let supported = leviath_sys::keychain::is_supported();

    let providers: Vec<String> = config
        .provider_secrets()
        .into_iter()
        .map(|(account, _)| account)
        .collect();

    // Read the file directly rather than through `Config::load`: the loader
    // already folded the keychain in, so it cannot tell the two sources apart.
    let on_disk = providers_in_file(path);
    let (unavailable, in_store) = match resolved {
        Ok(Some(store)) => {
            let accounts: Vec<String> = crate::credentials::PROVIDER_KEYS
                .iter()
                .map(|p| leviath_core::provider_account(p))
                .collect();
            (None, store.read_all(&accounts).into_keys().collect())
        }
        Ok(None) => (None, Vec::new()),
        Err(e) => (Some(e), Vec::new()),
    };

    let duplicated = on_disk
        .iter()
        .filter(|a| in_store.contains(a))
        .cloned()
        .collect();

    // MCP grants live in their own store, keyed by server name. A load failure
    // is reported as "none" rather than propagated: `lev auth status` is the
    // command a user runs *because* something is wrong, so it has to answer.
    let mcp_servers = mcp_server_names(leviath_mcp::AuthStore::default_path().as_deref(), None);

    Status {
        kind,
        supported,
        unavailable,
        providers,
        mcp_servers,
        duplicated,
        config_path: path.display().to_string(),
    }
}

/// The provider accounts that have a key written in the config *file*.
///
/// Parsed straight out of the TOML because `Config::load` merges the
/// environment and the credential store in, which is exactly the distinction
/// this needs to make.
fn providers_in_file(path: &std::path::Path) -> Vec<String> {
    let Ok(text) = std::fs::read_to_string(path) else {
        return Vec::new();
    };
    let Ok(value) = text.parse::<toml::Table>() else {
        return Vec::new();
    };
    crate::credentials::PROVIDER_KEYS
        .iter()
        .filter(|p| file_has_key(&value, p))
        .map(|p| leviath_core::provider_account(p))
        .collect()
}

/// Whether the parsed config file carries a key for `provider`.
///
/// `openrouter_api_key` sits at the top level while the other three live under
/// `[providers]` - a historical split the config struct still reflects.
fn file_has_key(value: &toml::Table, provider: &str) -> bool {
    let field = format!("{provider}_api_key");
    if provider == "openrouter" {
        return value.get(&field).and_then(|v| v.as_str()).is_some();
    }
    value
        .get("providers")
        .and_then(|p| p.get(&field))
        .and_then(|v| v.as_str())
        .is_some()
}

/// Render a [`Status`] for the terminal.
pub(crate) fn render_status(s: &Status) -> String {
    let mut out = String::new();
    let backend = match s.kind {
        CredentialStoreKind::File => "file (Leviath's own 0600 files)",
        CredentialStoreKind::Keychain => "keychain (OS credential store)",
    };
    out.push_str(&format!("Credential store: {backend}\n"));
    out.push_str(&format!("Config file:      {}\n", s.config_path));

    if !s.supported {
        out.push_str(
            "\nThis build has no OS credential store support (the `keychain` feature is off).\n",
        );
    }
    if let Some(reason) = &s.unavailable {
        out.push_str(&format!("\n! {reason}\n"));
    }

    out.push('\n');
    if s.providers.is_empty() {
        out.push_str("No provider API keys are configured. Run `lev setup` to add one.\n");
    } else {
        out.push_str("Provider keys configured:\n");
        for p in &s.providers {
            out.push_str(&format!("  - {p}\n"));
        }
    }

    if !s.mcp_servers.is_empty() {
        out.push_str("\nMCP servers logged in:\n");
        for m in &s.mcp_servers {
            out.push_str(&format!("  - {m}\n"));
        }
    }

    if !s.duplicated.is_empty() {
        out.push_str(
            "\n! These are stored in BOTH the config file and the OS keychain. The file copy\n  \
             wins, so changing the keychain entry will appear to have no effect. Run\n  \
             `lev auth migrate` to remove the file copies.\n",
        );
        for p in &s.duplicated {
            out.push_str(&format!("  - {p}\n"));
        }
    }

    if s.kind == CredentialStoreKind::File && s.supported {
        out.push_str(
            "\nTo move these into the OS keychain, set `[security] credential_store = \"keychain\"`\n\
             in the config file and run `lev auth migrate`.\n",
        );
    }
    out
}

/// Move secrets between the config file and the OS credential store.
fn migrate(path: &std::path::Path, to_file: bool, dry_run: bool) -> anyhow::Result<()> {
    let config = Config::load_from_path_public(path)?;
    let plan = plan_migration(&config, to_file);

    if plan.moving.is_empty() {
        println!("{}", plan.summary);
        return Ok(());
    }

    println!("{}", plan.summary);
    for account in &plan.moving {
        println!("  - {account}");
    }
    if dry_run {
        println!("\nDry run: nothing was changed.");
        return Ok(());
    }

    apply_migration(&config, path, to_file)?;
    println!("\nDone. {}", plan.done);
    Ok(())
}

/// What a migration would do, computed without changing anything.
#[derive(Debug, PartialEq)]
pub(crate) struct MigrationPlan {
    pub moving: Vec<String>,
    pub summary: String,
    pub done: String,
}

pub(crate) fn plan_migration(config: &Config, to_file: bool) -> MigrationPlan {
    let moving: Vec<String> = config
        .provider_secrets()
        .into_iter()
        .map(|(account, _)| account)
        .collect();

    if moving.is_empty() {
        return MigrationPlan {
            moving,
            summary: "No provider API keys are configured; there is nothing to move.".to_string(),
            done: String::new(),
        };
    }

    let (summary, done) = if to_file {
        (
            "Moving these secrets out of the OS keychain and into the config file:",
            "The config file now holds these keys (mode 0600). Set `[security] \
             credential_store = \"file\"` if you have not already.",
        )
    } else {
        (
            "Moving these secrets into the OS keychain:",
            "The config file no longer contains these keys. Set `[security] \
             credential_store = \"keychain\"` if you have not already.",
        )
    };
    MigrationPlan {
        moving,
        summary: summary.to_string(),
        done: done.to_string(),
    }
}

/// Perform the move.
///
/// The order matters in both directions: write the destination first, verify it
/// took, and only then remove the source. A migration that cleared the config
/// file before the keychain write succeeded would destroy the user's API keys.
fn apply_migration(config: &Config, path: &std::path::Path, to_file: bool) -> anyhow::Result<()> {
    let resolved = crate::credentials::store_for(CredentialStoreKind::Keychain);
    apply_migration_with(
        config,
        path,
        to_file,
        resolved,
        leviath_mcp::AuthStore::default_path().as_deref(),
    )
}

/// Core of [`apply_migration`] with the keychain already resolved - see
/// [`status_with`] for why the resolution is the caller's.
fn apply_migration_with(
    config: &Config,
    path: &std::path::Path,
    to_file: bool,
    resolved: crate::credentials::Resolved,
    mcp_path: Option<&std::path::Path>,
) -> anyhow::Result<()> {
    let secrets = config.provider_secrets();

    if to_file {
        // The keys are already in `config` (the loader folded them in), so
        // saving with the file backend writes them out. Clear the keychain only
        // after that write has succeeded.
        let mut file_config = config.clone();
        file_config.security.credential_store = CredentialStoreKind::File;
        file_config.save_to_path_public(path)?;

        if let Ok(Some(store)) = resolved {
            for (account, _) in &secrets {
                // A failure to clean up is not a failure to migrate: the keys
                // are safely in the file, and a leftover keychain entry is
                // reported by `lev auth status` as a duplicate.
                if let Err(e) = store.delete(account) {
                    tracing::warn!("could not remove {account} from the keychain: {e}");
                }
            }
            // The MCP grants move the same direction: out of the keychain and
            // back into their own file.
            let names = mcp_server_names(mcp_path, Some(store.as_ref()));
            migrate_mcp_grants(mcp_path, Some(store.as_ref()), None)?;
            for name in names {
                if let Err(e) = store.delete(&leviath_core::mcp_account(&name)) {
                    tracing::warn!("could not remove the grant for '{name}': {e}");
                }
            }
        }
        return Ok(());
    }

    let store = resolved
        .map_err(|e| anyhow::anyhow!("{e}"))?
        .ok_or_else(|| anyhow::anyhow!("no OS credential store is available"))?;

    for (account, secret) in &secrets {
        store
            .set(account, secret)
            .map_err(|e| anyhow::anyhow!("failed to store {account}: {e}"))?;
        // Read it back before trusting it. A store that accepts a write and
        // returns nothing would otherwise lose the key when the file copy is
        // removed below.
        match store.get(account) {
            Ok(Some(v)) if &v == secret => {}
            _ => anyhow::bail!(
                "{account} did not read back correctly from the credential store; \
                 the config file has been left unchanged"
            ),
        }
    }

    // Only now is it safe to drop the file copies.
    let mut stripped = config.clone();
    stripped.security.credential_store = CredentialStoreKind::Keychain;
    stripped.save_to_path_public(path)?;

    migrate_mcp_grants(mcp_path, None, Some(store.as_ref()))
}

/// Rewrite the MCP auth store at `path`, moving its grants from `source` to
/// `destination`.
///
/// `None` on either side means the file itself. The grants are read through
/// whichever backend holds them today and written to the other, so this is the
/// same operation in both directions.
///
/// A missing path or a store that was never created is not an error: a user who
/// has never run `lev mcp login` has nothing to move.
fn migrate_mcp_grants(
    path: Option<&std::path::Path>,
    source: Option<&dyn CredentialStore>,
    destination: Option<&dyn CredentialStore>,
) -> anyhow::Result<()> {
    let Some(path) = path else {
        return Ok(());
    };
    if !path.exists() {
        return Ok(());
    }
    let store = leviath_mcp::AuthStore::load_with(path, source)?;
    store.save_with(path, destination)
}

/// The MCP servers with a stored grant, read through `store`.
fn mcp_server_names(
    path: Option<&std::path::Path>,
    store: Option<&dyn CredentialStore>,
) -> Vec<String> {
    path.and_then(|p| leviath_mcp::AuthStore::load_with(p, store).ok())
        .map(|s| {
            let mut names: Vec<String> = s
                .server_names()
                .into_iter()
                .map(str::to_string)
                .chain(s.keychain_server_names().iter().cloned())
                .collect();
            names.sort();
            names.dedup();
            names
        })
        .unwrap_or_default()
}

#[cfg(test)]
mod tests {
    use super::*;

    use crate::credentials::test_store;

    fn with_mock_store() -> std::sync::MutexGuard<'static, ()> {
        test_store::with_mock()
    }

    /// The keychain backend, resolved against whatever store is installed.
    fn keychain() -> crate::credentials::Resolved {
        crate::credentials::store_for(CredentialStoreKind::Keychain)
    }

    /// A store whose three operations answer however a test needs.
    ///
    /// One configurable stub rather than a bespoke struct per test: a struct
    /// with a `delete` no test ever calls is an uncovered method, and the point
    /// here is the *combination* of answers, not the type.
    struct Stub {
        get: fn(&str) -> Result<Option<String>, String>,
        set: fn(&str, &str) -> Result<(), String>,
        delete: fn(&str) -> Result<bool, String>,
    }

    impl CredentialStore for Stub {
        fn get(&self, account: &str) -> Result<Option<String>, String> {
            (self.get)(account)
        }
        fn set(&self, account: &str, secret: &str) -> Result<(), String> {
            (self.set)(account, secret)
        }
        fn delete(&self, account: &str) -> Result<bool, String> {
            (self.delete)(account)
        }
    }

    fn absent(_: &str) -> Result<Option<String>, String> {
        Ok(None)
    }
    fn accepts_write(_: &str, _: &str) -> Result<(), String> {
        Ok(())
    }
    fn refuses_write(_: &str, _: &str) -> Result<(), String> {
        Err("read-only keychain".to_string())
    }
    fn refuses_delete(_: &str) -> Result<bool, String> {
        Err("cannot delete".to_string())
    }

    /// Make `path` unwritable, and undo it.
    ///
    /// `set_readonly` rather than a `0400` chmod: it clears the write bits on
    /// Unix *and* sets the read-only attribute on Windows, so the "the rewrite
    /// failed" tests run on every platform. Gated to Unix they left the `?` arms
    /// they cover unexercised on Windows, which the gate then failed on.
    fn set_readonly(path: &std::path::Path, readonly: bool) {
        let mut perms = std::fs::metadata(path).unwrap().permissions();
        perms.set_readonly(readonly);
        std::fs::set_permissions(path, perms).unwrap();
    }

    /// The keychain backend on a machine that has none.
    fn no_keychain() -> crate::credentials::Resolved {
        Err(
            "`[security] credential_store = \"keychain\"` is set, but OS \
             credential store unavailable: no default store"
                .to_string(),
        )
    }

    fn config_with_keys(kind: CredentialStoreKind) -> Config {
        let mut c = Config::default();
        c.security.credential_store = kind;
        c.providers.anthropic_api_key = Some("sk-ant-secret".into());
        c.openrouter_api_key = Some("sk-or-secret".into());
        c
    }

    /// The end-to-end move: keys start in the file, end in the keychain, and
    /// the file no longer contains them.
    #[test]
    fn migrating_to_the_keychain_moves_the_secrets_out_of_the_file() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");

        let config = config_with_keys(CredentialStoreKind::File);
        config.save_to_path_public(&path).unwrap();
        let before = std::fs::read_to_string(&path).unwrap();
        assert!(before.contains("sk-ant-secret"), "the file starts with it");

        apply_migration_with(&config, &path, false, keychain(), None).unwrap();

        let after = std::fs::read_to_string(&path).unwrap();
        assert!(
            !after.contains("sk-ant-secret") && !after.contains("sk-or-secret"),
            "no secret may remain in the file: {after}"
        );

        let store = crate::credentials::store_for(CredentialStoreKind::Keychain)
            .unwrap()
            .unwrap();
        assert_eq!(
            store
                .get(&leviath_core::provider_account("anthropic"))
                .unwrap()
                .as_deref(),
            Some("sk-ant-secret")
        );
        assert_eq!(
            store
                .get(&leviath_core::provider_account("openrouter"))
                .unwrap()
                .as_deref(),
            Some("sk-or-secret")
        );
    }

    /// And back again, so the keychain is not a one-way door.
    #[test]
    fn migrating_to_the_file_restores_the_secrets_and_clears_the_keychain() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");

        let config = config_with_keys(CredentialStoreKind::Keychain);
        apply_migration_with(&config, &path, false, keychain(), None).unwrap();
        apply_migration_with(&config, &path, true, keychain(), None).unwrap();

        let after = std::fs::read_to_string(&path).unwrap();
        assert!(after.contains("sk-ant-secret"), "back in the file: {after}");

        let store = crate::credentials::store_for(CredentialStoreKind::Keychain)
            .unwrap()
            .unwrap();
        assert_eq!(
            store
                .get(&leviath_core::provider_account("anthropic"))
                .unwrap(),
            None,
            "and gone from the keychain"
        );
    }

    /// The safety property that matters most: if the credential store cannot be
    /// written, the config file must be left alone. Losing the user's API keys
    /// to a half-finished migration is the worst outcome available here.
    #[test]
    fn a_failing_store_leaves_the_config_file_untouched() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::File);
        config.save_to_path_public(&path).unwrap();
        let before = std::fs::read_to_string(&path).unwrap();

        assert!(
            apply_migration_with(&config, &path, false, no_keychain(), None).is_err(),
            "no store means no migration"
        );
        assert_eq!(
            std::fs::read_to_string(&path).unwrap(),
            before,
            "the file must be byte-identical after a failed migration"
        );
    }

    /// A store that silently drops writes must be caught by the read-back,
    /// before the file copies are removed. Without it, `set` succeeding would be
    /// taken as proof and the only copy of the key would be deleted.
    #[test]
    fn a_store_that_does_not_persist_aborts_before_the_file_is_stripped() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::File);
        config.save_to_path_public(&path).unwrap();
        let before = std::fs::read_to_string(&path).unwrap();

        // Accepts the write, then reports nothing back.
        let amnesiac = Stub {
            get: absent,
            set: accepts_write,
            delete: refuses_delete,
        };
        let err = apply_migration_with(&config, &path, false, Ok(Some(Box::new(amnesiac))), None)
            .expect_err("a store that does not persist must not be trusted");
        assert!(err.to_string().contains("did not read back"), "{err}");
        assert_eq!(
            std::fs::read_to_string(&path).unwrap(),
            before,
            "and the file is untouched"
        );
    }

    /// A store that refuses the write at all is caught the same way.
    #[test]
    fn a_store_that_refuses_the_write_aborts_the_migration() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::File);

        let refuses = Stub {
            get: absent,
            set: refuses_write,
            delete: refuses_delete,
        };
        let err = apply_migration_with(&config, &path, false, Ok(Some(Box::new(refuses))), None)
            .expect_err("a refused write is not a migration");
        assert!(err.to_string().contains("failed to store"), "{err}");
    }

    /// Migrating *to* the file is not blocked by a keychain that cannot be
    /// cleaned up: the keys are already safely written, and a leftover entry is
    /// reported by `lev auth status` as a duplicate rather than lost data.
    #[test]
    fn cleanup_failures_do_not_fail_a_migration_to_the_file() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::Keychain);

        let undeletable = Stub {
            get: absent,
            set: accepts_write,
            delete: refuses_delete,
        };
        // A real MCP store too, so the grant cleanup runs and its failure is
        // shown to be non-fatal as well.
        let mcp = dir.path().join("mcp-auth.json");
        write_mcp_store(&mcp, "github");

        apply_migration_with(
            &config,
            &path,
            true,
            Ok(Some(Box::new(undeletable))),
            Some(&mcp),
        )
        .expect("the keys are in the file; cleanup is best effort");
        let after = std::fs::read_to_string(&path).unwrap();
        assert!(after.contains("sk-ant-secret"), "{after}");
    }

    /// The ordinary to-file path: both the provider keys and the MCP grants come
    /// back, and the keychain entries are cleaned up without incident.
    #[test]
    fn migrating_to_the_file_also_brings_back_the_mcp_grants() {
        use leviath_core::CredentialStore as _;

        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let mcp = dir.path().join("mcp-auth.json");
        let config = config_with_keys(CredentialStoreKind::Keychain);

        // Put a grant in the store, and leave the file holding only the index.
        let store = leviath_core::MemoryStore::new();
        write_mcp_store(&mcp, "github");
        migrate_mcp_grants(Some(&mcp), None, Some(&store)).unwrap();
        assert!(!std::fs::read_to_string(&mcp).unwrap().contains("rt-SECRET"));
        store
            .set(
                &leviath_core::provider_account("anthropic"),
                "sk-ant-secret",
            )
            .unwrap();

        apply_migration_with(&config, &path, true, Ok(Some(Box::new(store))), Some(&mcp)).unwrap();

        assert!(
            std::fs::read_to_string(&mcp).unwrap().contains("rt-SECRET"),
            "the grant is back in its own file"
        );
    }

    /// A corrupt MCP store must fail the migration rather than be reported as a
    /// completed move that silently dropped every login.
    #[test]
    fn a_corrupt_mcp_store_fails_a_migration_to_the_file() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let mcp = dir.path().join("mcp-auth.json");
        std::fs::write(&mcp, "not json").unwrap();

        let config = config_with_keys(CredentialStoreKind::Keychain);
        let store = leviath_core::MemoryStore::new();
        let err = apply_migration_with(&config, &path, true, Ok(Some(Box::new(store))), Some(&mcp))
            .expect_err("a corrupt MCP store is not a successful migration");
        assert!(!err.to_string().is_empty());
    }

    /// And a migration to the file still works when there is no keychain at all
    /// to clean up.
    #[test]
    fn migrating_to_the_file_works_without_a_keychain() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::Keychain);
        apply_migration_with(&config, &path, true, no_keychain(), None).unwrap();
        assert!(
            std::fs::read_to_string(&path)
                .unwrap()
                .contains("sk-ant-secret")
        );
    }

    /// The rewrite that completes a move into the keychain has to be able to
    /// fail: the secrets are already in the store, but the config still names
    /// them, and reporting success would be a lie.
    #[test]
    fn a_failed_final_rewrite_fails_the_migration() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::File);
        config.save_to_path_public(&path).unwrap();
        set_readonly(&path, true);

        let err = apply_migration_with(&config, &path, false, keychain(), None)
            .expect_err("an unwritable config cannot complete the move");
        assert!(!err.to_string().is_empty());

        set_readonly(&path, false);
    }

    /// `Ok(None)` - the file backend where a keychain was expected - is a
    /// refusal, not a silent no-op that would strip the file.
    #[test]
    fn migrating_to_a_backend_that_is_not_a_store_is_refused() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::File);
        let err = apply_migration_with(&config, &path, false, Ok(None), None)
            .expect_err("there is nowhere to migrate to");
        assert!(err.to_string().contains("no OS credential store"), "{err}");
    }

    #[test]
    fn the_plan_lists_every_configured_key_and_says_nothing_when_there_are_none() {
        let plan = plan_migration(&config_with_keys(CredentialStoreKind::File), false);
        assert_eq!(plan.moving.len(), 2);
        assert!(plan.summary.contains("into the OS keychain"));

        let back = plan_migration(&config_with_keys(CredentialStoreKind::Keychain), true);
        assert!(back.summary.contains("out of the OS keychain"));
        assert!(back.done.contains("credential_store = \"file\""));

        let empty = plan_migration(&Config::default(), false);
        assert!(empty.moving.is_empty());
        assert!(empty.summary.contains("nothing to move"));
    }

    /// The duplicate warning: a key in both places is not an error, but the file
    /// copy wins, so rotating the keychain entry would silently do nothing.
    #[test]
    fn status_reports_a_secret_stored_in_both_places() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");

        // Written with the file backend, so the key lands in the TOML...
        let config = config_with_keys(CredentialStoreKind::File);
        config.save_to_path_public(&path).unwrap();
        // ...and also placed in the keychain.
        let store = crate::credentials::store_for(CredentialStoreKind::Keychain)
            .unwrap()
            .unwrap();
        store
            .set(
                &leviath_core::provider_account("anthropic"),
                "sk-ant-secret",
            )
            .unwrap();

        let mut keychain_config = config.clone();
        keychain_config.security.credential_store = CredentialStoreKind::Keychain;
        let s = status_with(&keychain_config, &path, keychain());

        assert_eq!(s.duplicated, vec!["provider/anthropic".to_string()]);
        let rendered = render_status(&s);
        assert!(rendered.contains("BOTH"), "{rendered}");
        assert!(rendered.contains("lev auth migrate"), "{rendered}");
    }

    #[test]
    fn status_on_a_plain_file_install_says_so_and_offers_the_keychain() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::File);
        config.save_to_path_public(&path).unwrap();

        let s = status_with(&config, &path, Ok(None));
        assert_eq!(s.kind, CredentialStoreKind::File);
        assert!(s.unavailable.is_none(), "the file backend needs no store");
        assert!(s.duplicated.is_empty());
        assert_eq!(s.providers.len(), 2);

        let rendered = render_status(&s);
        assert!(rendered.contains("file (Leviath's own 0600 files)"));
        assert!(rendered.contains("credential_store = \"keychain\""));
    }

    /// An unavailable keychain has to be reported rather than looking like an
    /// empty one.
    #[test]
    fn status_reports_an_unreachable_keychain() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");

        let s = status_with(
            &config_with_keys(CredentialStoreKind::Keychain),
            &path,
            no_keychain(),
        );
        assert!(s.unavailable.is_some());
        let rendered = render_status(&s);
        assert!(
            rendered.contains("credential store unavailable"),
            "{rendered}"
        );
    }

    #[test]
    fn status_with_no_keys_points_at_setup() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let s = status_with(&Config::default(), &path, Ok(None));
        assert!(s.providers.is_empty());
        let rendered = render_status(&s);
        assert!(rendered.contains("lev setup"), "{rendered}");
    }

    /// A build compiled without keychain support must say so rather than
    /// offering a migration that cannot work.
    #[test]
    fn a_build_without_keychain_support_says_so() {
        let s = Status {
            kind: CredentialStoreKind::File,
            supported: false,
            unavailable: None,
            providers: vec!["provider/anthropic".into()],
            mcp_servers: Vec::new(),
            duplicated: Vec::new(),
            config_path: "/x/config.toml".into(),
        };
        let rendered = render_status(&s);
        assert!(
            rendered.contains("no OS credential store support"),
            "{rendered}"
        );
        assert!(
            !rendered.contains("credential_store = \"keychain\""),
            "and must not suggest a backend it cannot use: {rendered}"
        );
    }

    /// The file scan has to tell the top-level `openrouter_api_key` apart from
    /// the three under `[providers]`, and must not fall over on an unreadable or
    /// malformed file.
    #[test]
    fn the_file_scan_finds_keys_in_both_shapes_and_tolerates_a_bad_file() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");

        assert!(
            providers_in_file(&path).is_empty(),
            "a missing file is empty"
        );

        std::fs::write(&path, "this is not toml = = =").unwrap();
        assert!(providers_in_file(&path).is_empty(), "so is a broken one");

        std::fs::write(
            &path,
            "openrouter_api_key = \"a\"\n[providers]\nanthropic_api_key = \"b\"\n",
        )
        .unwrap();
        let found = providers_in_file(&path);
        assert!(found.contains(&"provider/openrouter".to_string()));
        assert!(found.contains(&"provider/anthropic".to_string()));
        assert_eq!(found.len(), 2, "and nothing else: {found:?}");
    }

    /// `migrate` must propagate a failed migration rather than reporting
    /// success. Here the config file itself is read-only, so the rewrite that
    /// completes the move cannot happen.
    #[test]
    fn migrate_propagates_a_failed_move() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        config_with_keys(CredentialStoreKind::File)
            .save_to_path_public(&path)
            .unwrap();
        // Readable, so the load succeeds; unwritable, so the rewrite does not.
        set_readonly(&path, true);

        let err = run_auth(&path, AuthArgs::migrate_for_test(true, false))
            .expect_err("an unwritable config cannot be migrated");
        assert!(!err.to_string().is_empty());

        set_readonly(&path, false);
    }

    /// Writing a grant into a temporary MCP auth store, so the migration
    /// helpers have something to move.
    fn write_mcp_store(path: &std::path::Path, server: &str) {
        let mut store = leviath_mcp::AuthStore::default();
        store.set(
            server,
            leviath_mcp::ServerAuth {
                resource: "https://example.test/mcp".to_string(),
                issuer: "https://example.test".to_string(),
                authorization_endpoint: "https://example.test/authorize".to_string(),
                token_endpoint: "https://example.test/token".to_string(),
                client_id: "cid".to_string(),
                access_token: "at-SECRET".to_string(),
                refresh_token: Some("rt-SECRET".to_string()),
                expires_at: 9_999_999_999,
                scope: String::new(),
            },
        );
        store.save(path).unwrap();
    }

    /// MCP OAuth grants move with the provider keys: tokens out of the file,
    /// only the server name left behind as an index.
    #[test]
    fn mcp_grants_move_into_the_credential_store_and_back() {
        let dir = tempfile::tempdir().unwrap();
        let mcp = dir.path().join("mcp-auth.json");
        write_mcp_store(&mcp, "github");
        assert!(std::fs::read_to_string(&mcp).unwrap().contains("rt-SECRET"));

        let store = leviath_core::MemoryStore::new();
        migrate_mcp_grants(Some(&mcp), None, Some(&store)).unwrap();

        let on_disk = std::fs::read_to_string(&mcp).unwrap();
        assert!(!on_disk.contains("rt-SECRET"), "{on_disk}");
        assert!(!on_disk.contains("at-SECRET"), "{on_disk}");
        assert!(on_disk.contains("github"), "the index remains: {on_disk}");
        assert_eq!(mcp_server_names(Some(&mcp), Some(&store)), ["github"]);

        // ...and back again.
        migrate_mcp_grants(Some(&mcp), Some(&store), None).unwrap();
        let restored = std::fs::read_to_string(&mcp).unwrap();
        assert!(restored.contains("rt-SECRET"), "{restored}");
    }

    /// Nothing to move is not an error - a user who has never run
    /// `lev mcp login` has no store, and no home is not a failure either.
    #[test]
    fn migrating_mcp_grants_is_a_no_op_when_there_is_nothing_to_move() {
        let dir = tempfile::tempdir().unwrap();
        let missing = dir.path().join("mcp-auth.json");

        migrate_mcp_grants(None, None, None).expect("no path, nothing to do");
        migrate_mcp_grants(Some(&missing), None, None).expect("no file, nothing to do");
        assert!(mcp_server_names(None, None).is_empty());
        assert!(mcp_server_names(Some(&missing), None).is_empty());
    }

    /// A corrupt MCP store fails the migration rather than silently discarding
    /// every stored grant.
    #[test]
    fn a_corrupt_mcp_store_fails_the_migration() {
        let dir = tempfile::tempdir().unwrap();
        let mcp = dir.path().join("mcp-auth.json");
        std::fs::write(&mcp, "not json").unwrap();

        assert!(migrate_mcp_grants(Some(&mcp), None, None).is_err());
        // The reporting path is more forgiving: `lev auth status` is the command
        // a user runs *because* something is wrong, so it answers with "none"
        // rather than refusing to run.
        assert!(mcp_server_names(Some(&mcp), None).is_empty());
    }

    /// The status report lists logged-in MCP servers.
    #[test]
    fn status_lists_mcp_servers() {
        let s = Status {
            kind: CredentialStoreKind::Keychain,
            supported: true,
            unavailable: None,
            providers: vec!["provider/anthropic".into()],
            mcp_servers: vec!["github".into(), "linear".into()],
            duplicated: Vec::new(),
            config_path: "/x/config.toml".into(),
        };
        let rendered = render_status(&s);
        assert!(rendered.contains("MCP servers logged in"), "{rendered}");
        assert!(rendered.contains("- github"), "{rendered}");
        assert!(rendered.contains("- linear"), "{rendered}");
    }

    /// A config file that cannot be parsed must fail the command rather than
    /// being treated as an empty install - both entry points read it.
    #[test]
    fn a_broken_config_file_fails_both_subcommands() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        std::fs::write(&path, "this is not = = toml").unwrap();

        assert!(
            run_auth(&path, AuthArgs::status_for_test()).is_err(),
            "status must not report a broken config as an empty one"
        );
        assert!(
            run_auth(&path, AuthArgs::migrate_for_test(false, false)).is_err(),
            "and migrate must not act on one"
        );
    }

    /// A migration whose write fails has to surface through `migrate`, not just
    /// through `apply_migration_with`.
    #[test]
    fn migrate_reports_a_failing_store() {
        let _guard = test_store::lock();
        // No store installed: `store_for` probes, and on a machine with a real
        // keychain that would reach it - so drive the seam directly instead.
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        let config = config_with_keys(CredentialStoreKind::File);
        config.save_to_path_public(&path).unwrap();

        let refuses = Stub {
            get: absent,
            set: refuses_write,
            delete: refuses_delete,
        };
        assert!(
            apply_migration_with(&config, &path, false, Ok(Some(Box::new(refuses))), None).is_err()
        );
    }

    /// The `to_file` direction writes the config first; an unwritable path has
    /// to fail rather than silently clearing the keychain.
    #[test]
    fn migrating_to_an_unwritable_path_fails_before_touching_the_keychain() {
        let dir = tempfile::tempdir().unwrap();
        // A file where a parent directory would have to be.
        let blocker = dir.path().join("blocker");
        std::fs::write(&blocker, b"x").unwrap();
        let path = blocker.join("config.toml");

        let config = config_with_keys(CredentialStoreKind::Keychain);
        assert!(
            apply_migration_with(&config, &path, true, no_keychain(), None).is_err(),
            "an unwritable destination is not a migration"
        );
    }

    /// Drive `execute` - the real entry point - for each subcommand, against a
    /// config path of our choosing.
    ///
    /// Plain `#[test]`s driving their own runtime rather than `#[tokio::test]`:
    /// the mock-store guard has to be held across the whole call, and holding a
    /// `std` guard across an `.await` is a deadlock the scheduler is free to
    /// arrange.
    fn run_auth(path: &std::path::Path, args: AuthArgs) -> anyhow::Result<()> {
        let rt = tokio::runtime::Builder::new_current_thread()
            .enable_all()
            .build()
            .unwrap();
        temp_env::with_var("LEVIATH_CONFIG_PATH", Some(path.as_os_str()), || {
            rt.block_on(execute(args))
        })
    }

    #[test]
    fn execute_status_reads_the_configured_path() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        config_with_keys(CredentialStoreKind::File)
            .save_to_path_public(&path)
            .unwrap();

        run_auth(&path, AuthArgs::status_for_test()).expect("status succeeds");
    }

    /// `--dry-run` reports the plan and changes nothing.
    #[test]
    fn execute_migrate_dry_run_changes_nothing() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        config_with_keys(CredentialStoreKind::File)
            .save_to_path_public(&path)
            .unwrap();
        let before = std::fs::read_to_string(&path).unwrap();

        run_auth(&path, AuthArgs::migrate_for_test(false, true)).expect("dry run succeeds");
        assert_eq!(
            std::fs::read_to_string(&path).unwrap(),
            before,
            "a dry run must not touch the file"
        );
    }

    /// And the real thing, through the command rather than the helper.
    #[test]
    fn execute_migrate_moves_the_keys() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        config_with_keys(CredentialStoreKind::File)
            .save_to_path_public(&path)
            .unwrap();

        run_auth(&path, AuthArgs::migrate_for_test(false, false)).expect("migrate succeeds");
        let after = std::fs::read_to_string(&path).unwrap();
        assert!(!after.contains("sk-ant-secret"), "{after}");
    }

    /// With nothing configured there is nothing to move, and that is reported
    /// rather than treated as an error.
    #[test]
    fn execute_migrate_with_no_keys_is_a_no_op() {
        let _guard = with_mock_store();
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        Config::default().save_to_path_public(&path).unwrap();

        run_auth(&path, AuthArgs::migrate_for_test(false, false)).expect("nothing to do succeeds");
    }
}