fix(custom-model): keep the launch model out of the stored config

Quick-start wrote a selection's launchModel into the session's stored
<Mode>Config, which is what a clear falls back to, so a clear relaunched
the CLI with the endpoint's model id on its native backend. Only API
callers can reach that, since no page sends a clear.

The first launch now takes the forced model from the session's selection,
through the same _withCustomModelLaunchModel() the respawn path uses, so
the stored config keeps the model chosen at create. That also carries the
model onto a new tmux session for a selection applied to a running
session, which the create path used to lose.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture-invariants.md

@@ -662,7 +662,7 @@ Adding the header changed the preamble, so `CODEMAN_PREAMBLE` was bumped (1.22.0
 
 ⚠️ The actual per-CLI redirect is `capabilities.customModelInjection` on the CLI registry (four kinds: `env` for claude/gemini/copilot, `configContentEnv` reusing opencode's existing `OPENCODE_CONFIG_CONTENT`, `configDir` for codex/pi/grok/omp/deepseek, writes an isolated per-session config file, NEVER the user's real `~/.codex`/`~/.pi`/`~/.omp`/grok config/dsh home; deepseek's redirect is a per-session `DSH_HOME` holding only the generated `cordis.patch.yml`, whose `linkFromRealHome` recipe field symlinks `profiles`/`sessions`/`settings.yaml` back out of the real dsh home (resolved session-`DSH_HOME`-first, lstat-guarded so a dangling link survives re-apply) instead of stranding them, and `unsupported` for antigravity, which has no known mechanism), computed by the pure `custom-model-injection.ts` (mirrors `session-cli-builder.ts`'s no-IO discipline). ⚠️ `PI_CONFIG_DIR` does NOTHING for pi or omp (grepped pi's entire bundled JS source, the string appears nowhere); both hardcode `~/.pi/agent/models.json` / `~/.omp/agent/models.yml` with no dedicated override, so the real redirect for both is the child process's own **`HOME`**, and both need `models` as an ARRAY of `{id}` objects (an object keyed by id silently loads zero models). Grok's real mechanism turned out to be a `config.toml` `[model.<name>]` block redirected via `GROK_HOME`, its original env-var-based recipe was flat-out wrong (produced "Not signed in" against a real binary), not just unverified.
 
-⚠️ **Two launch paths, chosen by mechanism, not preference**: opencode/codex/gemini/pi/grok/deepseek/omp apply the selection ONE-SHOT, before the session/process ever exists, with no restart at all; claude alone still applies a selection by **restarting the session's CLI process in place** via `Session.restartCli()`, a de-restricted `reattachRemote()` reusing the same `respawn-pane -k` primitive local/remote respawns already share, because every one of these harnesses reads its endpoint config at process start, never per-turn, so there is no live hot-swap; `Session.setCustomModel()` undoes the PREVIOUS selection's env keys (and deletes its old `configDir`) before merging the new ones in, so switching endpoints or clearing back to native cloud never leaves a stale key behind. It also puts back what the session had set itself under an injected key (`CustomModelBookkeeping.ownEnv`, read after the undo so a switch carries it across): an own `DSH_HOME` or `CLAUDE_CONFIG_DIR` used to be deleted with the injected value, which moved the session to the server's tree or the default Claude account. ⚠️ `ownEnv` can hold a credential in memory, so `getCustomModelForPersist()` writes only its `homeEnvVar` entry, and only as an absolute path (the registry types that name as any env var, so a `clis.json` override can point it at a credential), which it must write because the selection overwrote the tmux `setenv` that was the only other copy. `_restoreCustomModel()` always states `ownEnv` (empty for an older record) after `clampEnvOverridesForOwner()`: after a restart `_envOverrides` holds what the previous run INJECTED, and reading that as the session's own would pin it to a directory the clear deletes. The re-apply's real-home lookup has the same rule: the route reads `Session.ownEnvValue()` and recovery that clamped record (probed under the bulk cap, since it walks every saved session), never `envOverrideValue()`, so an entry the own home lacks is skipped rather than filled from the server's home. Quick-start hands the `Session` constructor the caller's overrides alone so `setCustomModel()` can see them. ⚠️ Deleting a key from `_envOverrides` is NOT enough on its own: `tmux setenv` persists at the tmux-session level and is inherited by `respawn-pane` (measured: `setenv FOO bar` survived two successive `respawn-pane -k`), so the retired keys are queued (`_pendingEnvUnsets`) and ride `RespawnPaneOptions.unsetEnvKeys` into `applyEnvOverrides()`, which `setenv -u`s them BEFORE re-applying the live overrides. ⚠️ `restartCli()` relaunches a CLI in an existing pane, so a CLI whose launch declares a `fallback` chain (claude) gets a conversation pinned as `resumeSessionId` for that one respawn: `--session-id <id>` refuses an id that already has a transcript (`Session ID ... is already in use`), and without the `--resume <id> || --session-id <id>` shape the docker/remote pane commands already use, applying a model killed the pane and lost the session. ⚠️ The pin looks in `<isolated>/projects`, so `linkSharedProjectsDir()` links it from the session's own `CLAUDE_CONFIG_DIR` when it has one (`guardSessionConfigDirHome()` covers `configDirVar` too): the server's tree would hide the conversation on apply and leave the endpoint's transcript behind on clear. The dead-pane respawn shares this pin, see [Dead-pane respawn: the resume pin](#dead-pane-respawn-the-resume-pin). ⚠️ pi, omp and grok need the config file AND a `model` launch param (`custom/<id>` for pi/omp, grok's `[model.codeman-custom]` block name), and codex gets one too (`--model <bare modelId>`, its pattern changed to `model-plain-colon`, which admits qwen3-style colon ids and requires a letter or digit first, for the native App Settings Codex model too): that is the registry's `customModelInjection.launchModel` template, applied onto the respawn options through `legacyConfigField` by `_withCustomModelLaunchModel()`, never by id, and a model id the CLI's `model` token pattern cannot carry is refused with a 400 rather than silently dropped by the argv engine. ⚠️ Remote (SSH) and Docker sessions are REFUSED (400): their `restartCli()` reattaches a durable tmux rather than restarting the agent and the env lands on the local pane, so they used to report `restarted:true` and change nothing. The selection survives a Codeman restart as the disk-only `__customModel` (bookkeeping: env KEYS, config dir, launch model, `homeEnvVar` and the session's own home path; never an injected value, which carries the API key and is re-derived from the endpoint store on recovery, and never any other own value), the config dir is removed with the session, and every secret-bearing file (`custom-model-hosts.json`, the per-session config dir) is written 0600.
+⚠️ **Two launch paths, chosen by mechanism, not preference**: opencode/codex/gemini/pi/grok/deepseek/omp apply the selection ONE-SHOT, before the session/process ever exists, with no restart at all; claude alone still applies a selection by **restarting the session's CLI process in place** via `Session.restartCli()`, a de-restricted `reattachRemote()` reusing the same `respawn-pane -k` primitive local/remote respawns already share, because every one of these harnesses reads its endpoint config at process start, never per-turn, so there is no live hot-swap; `Session.setCustomModel()` undoes the PREVIOUS selection's env keys (and deletes its old `configDir`) before merging the new ones in, so switching endpoints or clearing back to native cloud never leaves a stale key behind. It also puts back what the session had set itself under an injected key (`CustomModelBookkeeping.ownEnv`, read after the undo so a switch carries it across): an own `DSH_HOME` or `CLAUDE_CONFIG_DIR` used to be deleted with the injected value, which moved the session to the server's tree or the default Claude account. ⚠️ `ownEnv` can hold a credential in memory, so `getCustomModelForPersist()` writes only its `homeEnvVar` entry, and only as an absolute path (the registry types that name as any env var, so a `clis.json` override can point it at a credential), which it must write because the selection overwrote the tmux `setenv` that was the only other copy. `_restoreCustomModel()` always states `ownEnv` (empty for an older record) after `clampEnvOverridesForOwner()`: after a restart `_envOverrides` holds what the previous run INJECTED, and reading that as the session's own would pin it to a directory the clear deletes. The re-apply's real-home lookup has the same rule: the route reads `Session.ownEnvValue()` and recovery that clamped record (probed under the bulk cap, since it walks every saved session), never `envOverrideValue()`, so an entry the own home lacks is skipped rather than filled from the server's home. Quick-start hands the `Session` constructor the caller's overrides alone so `setCustomModel()` can see them. ⚠️ Deleting a key from `_envOverrides` is NOT enough on its own: `tmux setenv` persists at the tmux-session level and is inherited by `respawn-pane` (measured: `setenv FOO bar` survived two successive `respawn-pane -k`), so the retired keys are queued (`_pendingEnvUnsets`) and ride `RespawnPaneOptions.unsetEnvKeys` into `applyEnvOverrides()`, which `setenv -u`s them BEFORE re-applying the live overrides. ⚠️ `restartCli()` relaunches a CLI in an existing pane, so a CLI whose launch declares a `fallback` chain (claude) gets a conversation pinned as `resumeSessionId` for that one respawn: `--session-id <id>` refuses an id that already has a transcript (`Session ID ... is already in use`), and without the `--resume <id> || --session-id <id>` shape the docker/remote pane commands already use, applying a model killed the pane and lost the session. ⚠️ The pin looks in `<isolated>/projects`, so `linkSharedProjectsDir()` links it from the session's own `CLAUDE_CONFIG_DIR` when it has one (`guardSessionConfigDirHome()` covers `configDirVar` too): the server's tree would hide the conversation on apply and leave the endpoint's transcript behind on clear. The dead-pane respawn shares this pin, see [Dead-pane respawn: the resume pin](#dead-pane-respawn-the-resume-pin). ⚠️ pi, omp and grok need the config file AND a `model` launch param (`custom/<id>` for pi/omp, grok's `[model.codeman-custom]` block name), and codex gets one too (`--model <bare modelId>`, its pattern changed to `model-plain-colon`, which admits qwen3-style colon ids and requires a letter or digit first, for the native App Settings Codex model too): that is the registry's `customModelInjection.launchModel` template, applied onto the create and respawn options through `legacyConfigField` by `_withCustomModelLaunchModel()`, never by id and never onto the stored `<Mode>Config` (that config is what a clear falls back to; the quick-start route used to write the launch model there, so a clear relaunched the endpoint's id on the native backend), and a model id the CLI's `model` token pattern cannot carry is refused with a 400 rather than silently dropped by the argv engine. ⚠️ Remote (SSH) and Docker sessions are REFUSED (400): their `restartCli()` reattaches a durable tmux rather than restarting the agent and the env lands on the local pane, so they used to report `restarted:true` and change nothing. The selection survives a Codeman restart as the disk-only `__customModel` (bookkeeping: env KEYS, config dir, launch model, `homeEnvVar` and the session's own home path; never an injected value, which carries the API key and is re-derived from the endpoint store on recovery, and never any other own value), the config dir is removed with the session, and every secret-bearing file (`custom-model-hosts.json`, the per-session config dir) is written 0600.
 
 ⚠️ **Security**: every env var this feature can redirect (`ANTHROPIC_BASE_URL`, `GOOGLE_GEMINI_BASE_URL`, `CODEX_HOME`, `GROK_HOME`, `HOME` for pi/omp, `OPENCODE_CONFIG_CONTENT`, etc.) is in that CLI's `privilegedEnvKeys` — several of these were reachable via the generic `envOverrides` field's prefix allowlist BEFORE this feature existed (the env allowlist is global and prefix-based, not per-CLI-scoped), so building this surfaced and closed a pre-existing gap rather than opening a new one. `ANTHROPIC_*` is deliberately NOT in claude's `allowedPrefixes` at all — Anthropic-traffic redirection can only happen through this feature's own admin-configured, SSRF-guarded route, never a plain client-supplied `envOverrides`.
 

docs/custom-model-endpoints.md

@@ -543,6 +543,11 @@ selection goes, on a clear or a switch to another endpoint. That is what
 keeps a session on its own `DSH_HOME`, `CODEX_HOME` or `GROK_HOME`, and on
 its own account through `CLAUDE_CONFIG_DIR` (the per-client-account case).
 
+The launch model goes the same way: a clear relaunches on the model the session
+was created with, or with none if it was created without one. A session an
+older build launched straight onto an endpoint saved that endpoint's model in
+its config, so its clear still relaunches on that id.
+
 ⚠️ Across a Codeman restart only the home directory comes back, and only as
 an absolute path. The selection overwrote the tmux `setenv` that held it, so
 its record in `state.json` keeps that one path (`ownEnv`), and a non-granted