Claude Code's own fixed per-turn overhead (system prompt + tool schemas,
~36.4K tokens measured live) can exceed a small local model's entire real
context before any conversation history exists to compact — confirmed
live twice as an in:0 out:0 failure on the very first message sent.
CLAUDE_CODE_MAX_CONTEXT_TOKENS cannot fix this: it only governs when
history gets compacted, and there is none on message one.
- exceedsSafeContextFloor() (custom-model-routes.ts): true when a CLI's
registry entry declares contextLengthVar (currently only claude) and
the model's discovered context is below CLAUDE_MIN_SAFE_CONTEXT_TOKENS
(40000). A no-op for every other CLI by construction.
- Both apply routes (POST /api/sessions/:id/custom-model and the
quick-start customModel path) check this before the swap-conflict
check and before launching/restarting anything, returning
{requiresContextWarning, modelId, contextLength, minSafeContextTokens}
— skipped when confirmed:true.
- Frontend: #customModelContextWarningModal + _confirmContextWarning/
_resolveContextWarningConfirm (session-ui.js), wired into both
_quickStartWithCustomModelConfirm and _runCustomModelEntryViaRestart
(the path Claude actually uses) ahead of the swap-confirmation check.
Explains the fix in-modal: give the model an explicit larger -c/
--ctx-size in llama-swap instead of relying on --fit-ctx, which
optimizes for the biggest model that fits rather than the biggest
context.
Tests added for the route-level warning/confirm/skip cases and the
frontend modal + launch-flow wiring. Docs updated (custom-model-
endpoints.md, wiki/Custom-Model-Endpoints.md) and the PR's running
changeset extended.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RqZeHrRS6DYcGcGX2p9EwG
Fixes the visible double-launch reported on Codex: picking a custom-model
Run-menu entry launched natively first, waited for it to settle, then
restarted it in place with the endpoint applied. Necessary for the design at
the time, but visibly a native boot immediately followed by a second one -
worst on a CLI whose TUI fully reinitializes on a restart, confirmed live on
Codex.
POST /api/quick-start gains an optional customModel field
({endpointId, modelId, confirmed?}). When present, the route mints the
session's id itself (crypto.randomUUID()) before constructing it, computes
the same injection the existing POST /api/sessions/:id/custom-model route
computes (including the llama-swap conflict check from the last commit -
same {requiresConfirmation, currentlyLoadedModel, affectedSessions} shape,
no session created until confirmed), and launches the session already
pointed at the endpoint: env vars via the constructor, and the launchModel
override merged onto piConfig/grokConfig/ompConfig using the registry's own
launch.legacyConfigField the same way session.ts's restart path already
does. No restart at all - setCustomModel() afterward is bookkeeping only.
Wired into 7 of 8 launch functions (session-ui.js): openCode, codex, gemini,
pi, grok, deepseek, omp. Claude stays on the original launch-then-restart
path for now: its own --resume-based restart is far less jarring than the
other seven's, and runClaude()'s multi-tab launch plus docker-config-drift
confirm/retry loop make folding it into the one-shot path separate,
higher-risk work than the other seven's each-a-single-simple-launch shape.
Also fixes a pre-existing 'mode === omp' branch flagged by the CLI-id
static guard (test/cli-registry-no-id-branching.test.ts) - the ompConfig
launchModel merge is the same 'legacy <Mode>Config plumbing' category as
the six sibling branches already allowlisted there, just newly literal
where it was previously only inside resolveOmpConfigForCreate's own check.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RqZeHrRS6DYcGcGX2p9EwG
Covers #430's full scope so far: the picker itself, the model-selection
dialog, periodic re-discovery, and the session-busy/toast/CLAUDE_CONFIG_DIR/
context-length/llama-swap-conflict fixes found through live validation
against a real llama-swap server.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RqZeHrRS6DYcGcGX2p9EwG
