feat(canvas): phase 5 — run history, debug panel, error UX

.claude/gw-plans/canvas/README.md

@@ -9,7 +9,7 @@ React 19 + React Flow frontend phases. Depends on execution phases 3-4 for API s
 | 1 | [Canvas core](phase-1-canvas-core/overview.md) -- Home view, Start/LLM/End nodes, edge wiring, config panel, save/load | Complete |
 | 2 | [SSE run panel](phase-2-sse-run-panel/overview.md) -- SSE streaming, run panel, node highlighting, reconnection, resume | Complete |
 | 3 | [Full node set](phase-3-full-node-set/overview.md) -- Tool/Condition/HumanInput nodes, settings page, run input dialog, graph traversal, auto-map | Complete |
-| 4 | [State panel + LLM wiring](phase-4-state-panel/overview.md) -- LLM output_key clean break, LLM input_map/output_key config, state panel, model fetching | Not started |
+| 4 | [State panel + LLM wiring](phase-4-state-panel/overview.md) -- LLM output_key clean break, LLM input_map/output_key config, state panel, model fetching | Complete |
 | 5 | Error handling, run history, debug panel, JSON schema panel | Not started |
 | 6 | Python export, JSON read/write, dark mode, polish | Not started |
 

.claude/gw-plans/canvas/phase-4-state-panel/implementation-log.md

@@ -0,0 +1,65 @@
+# Phase 4 Implementation Log
+
+## PR #14 — feat(canvas): Phase 4 — state panel, input maps, model fetching, Radix Select
+
+Merged: 2026-03-20
+
+### What shipped
+
+**4.1 — LLM output_key clean break**
+- LLM nodes default to `output_key: "llm_response"` instead of `"messages"`
+- Execution layer appends AIMessage to messages history alongside writing to output_key
+- `DEFAULT_STATE` includes `llm_response` field
+- `isAutoOutputKey` + `deduplicateOutputKey` utilities for smart output_key naming
+
+**4.2 — LLM input_map + output_key config**
+- Full input_map editor in LLMNodeConfig (collapsed summary + expanded card editor)
+- Suggestion chips for upstream tool output fields
+- output_key field (hidden when terminal node)
+- `getRelevantFields` + `isTerminalNode` graph traversal utilities
+- `autoMapParams` with user_input assignment, enum-like detection, quoted literals
+- Type-filtered presets with `buildPresetsForParam`
+- Source node name hints via `resolveSourceHint` / `resolveSourceLabel`
+
+**4.3 — State panel**
+- Left sidebar Sheet with add/edit/remove state fields
+- AddFieldForm with type and reducer selection
+- StateFieldRow with inline editing, usage tracking, delete with undo toast
+- 3 entry points: toolbar icon, config panel link, dropdown "+ New field..."
+
+**4.4 — Model fetching**
+- `GET /v1/settings/providers` endpoint returns real model lists
+- `settingsSlice.loadProviders()` with fallback to hardcoded defaults
+- Collapsible "Model Settings" section in LLMNodeConfig
+
+**Bonus: Radix Select migration**
+- Replaced all native `<select>` with Radix-based Select component
+- `description` prop for secondary text in select items
+
+### Bug fixes (post-merge, same PR)
+
+**fix(canvas): cascade output_key renames to downstream node mappings**
+- `rewriteStateExpression()` utility for rewriting root keys in state expressions
+- `renameOutputKey()` store action: atomically updates source node, downstream input_maps, condition fields, and state entries
+- Blur-based cascade in ToolNodeConfig and LLMNodeConfig for manual edits
+- Tool-switch cascade in ToolNodeConfig
+
+**fix(canvas): create unique input fields when user_input already claimed**
+- `getClaimedInputKeys()` helper scans other nodes' input_maps for claimed root keys
+- `autoMapParams` extended with optional `claimedInputKeys` param
+- When `user_input` is claimed, creates `{param_name}_input` with dedup
+
+### Key decisions during implementation
+
+| Decision | Rationale |
+|----------|-----------|
+| Cascade on blur, not keystroke | Avoids rewriting downstream on every character typed in output_key |
+| `renameOutputKey` as atomic store action | Single state update for source node + all downstream + state field rename |
+| `claimedInputKeys` as optional param | Backward compatible — existing callers unaffected |
+| Radix Select in same PR | Needed for description prop; touching all selects anyway |
+
+### Test coverage
+
+- 464 tests passing after all changes
+- New test suites: `rewriteStateExpression`, `renameOutputKey`, `getClaimedInputKeys`, `autoMapParams` with claimed keys
+- Existing suites extended: `graphTraversal.test.ts`, `graphSlice.test.ts`, `presetUtils.test.ts`

.claude/gw-plans/canvas/phase-4-state-panel/overview.md

@@ -1,6 +1,6 @@
 # Canvas Phase 4 -- State Panel + LLM Wiring
 
-**Status: Not started**
+**Status: Complete**
 
 ## Goal