SugarCrush

A terminal AI coding agent — PHP port of charmbracelet/crush. It is a candy-core TEA program (a real Model/Program render loop with buffer-diffed output and Markdown-rendered replies) wrapped around a full agent engine: multiple LLM providers, model-driven tool calling gated by hooks, prompt-injecting skills, sub-agents, an MCP client/server, and SQLite session history.

┌─ SugarCrush ───────────────────────────────────────┐
│ user> add a test for the Width helper              │
│                                                    │
│ assistant                                          │
│ I'll read the helper first, then write the test.   │
│   ⚙ Read  src/Util/Width.php                       │
│   ⚙ Edit  tests/Util/WidthTest.php                 │
│ Done — added 4 cases covering the clamp edges.     │
└────────────────────────────────────────────────────┘
┌────────────────────────────────────────────────────┐
│ > run them█                                        │
└────────────────────────────────────────────────────┘
 Enter to send · Ctrl+P menu · /exit or ^C to quit

History: SugarCrush absorbed the former experimental candy-crush port. There is now a single SugarCraft\Crush library.

Run it

composer install
./bin/sugarcrush

With no configuration the binary runs the offline EchoProvider through the full engine, so it launches with zero network and zero keys. Point it at a real model with environment variables:

# OpenAI
export SUGARCRUSH_PROVIDER=openai
export OPENAI_API_KEY=sk-...
export SUGARCRUSH_MODEL=gpt-4o          # optional; provider default otherwise
./bin/sugarcrush

SUGARCRUSH_PROVIDER accepts openai, anthropic, claude-code, sglang, bedrock, vertex, or custom. Each reads its own credentials from the environment (e.g. ANTHROPIC_API_KEY, AWS ambient creds for Bedrock, GOOGLE_APPLICATION_CREDENTIALS for Vertex). When a real provider is active, the binary wires the built-in coding tools (Bash/Read/Edit/Glob/Grep/WebFetch/Doctor/Skill) and the safety hooks automatically.

Non-interactive (one-shot) mode

bin/sugarcrush parses argv before it constructs a Program, so the scriptable paths never attach to the TTY or enter the alt-screen:

sugarcrush -p "explain the Width helper"        # one prompt, print, exit
sugarcrush run "explain the Width helper"       # same thing
sugarcrush -p "audit this" --output-format json # machine-readable envelope
sugarcrush --root /path/to/project              # set the project root explicitly
sugarcrush --help                               # prints and exits (never opens the TUI)

--root also accepts the first positional argument that looks like a path, so sugarcrush ../other-project works. It is what the Bash/Read/Edit/Glob tools are jailed to and where CLAUDE.md/AGENTS.md and .sugar-crush/skills are looked for.

Dependency-free shell-out

To avoid PHP SDKs entirely, set SUGARCRUSH_BACKEND_CMD to a command that reads JSON history on stdin and writes the reply to stdout:

export SUGARCRUSH_BACKEND_CMD=~/bin/anthropic.sh
./bin/sugarcrush

#!/usr/bin/env bash
# ~/bin/anthropic.sh — keeps PHP network-dep-free, swap models by editing this file
payload=$(jq -nc --argjson h "$(cat)" '{model:"claude-opus-4-8", max_tokens:4096, messages:$h}')
curl -sN https://api.anthropic.com/v1/messages \
  -H "x-api-key: $ANTHROPIC_API_KEY" -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" -d "$payload" | jq -r '.content[0].text'

Choosing a backend without editing anything

Three ways to get off the offline EchoProvider, from quickest to most permanent:

1. One-off, this run only: SUGARCRUSH_PROVIDER=dev-sglang ./bin/sugarcrush — dev-sglang is the project's own dev/test SGLang endpoint (declared in .sugar-crush/config.dev.json, checked into the repo), useful for trying a real (if smaller) model with zero API keys.
2. From inside the TUI: press Ctrl+P, choose Switch model, pick any provider from the list (built-in types plus every name declared in .sugar-crush/config.dev.json, e.g. dev-sglang) — switches immediately, no restart. Switch theme works the same way for color themes.
3. Persisted across restarts: either of the above choices made via the palette is written to ~/.sugar-crush/config.json and read back on the next launch — so picking dev-sglang once via Ctrl+P means every future ./bin/sugarcrush (with no env vars set at all) uses it automatically. $SUGARCRUSH_PROVIDER/$SUGARCRUSH_BACKEND_CMD still take priority over the persisted choice when set, for scripting/CI overrides.

Using the TUI

The interactive binary boots a pane shell (App) that hosts the chat model, so the menu bar, pane strip, session tabs and the chat transcript are all one candy-core Model tree — not two parallel UIs.

Keys

Key	Does
Enter	Send
Esc Esc	Cancel the in-flight turn — press twice within 0.6s (a single Esc is a no-op, which is why the status bar reads Esc Esc to cancel while thinking)
Esc	Close the palette or the session picker
Ctrl+C	Quit
Ctrl+P	Command palette (fuzzy, grouped by category, biased by most-recently-used)
Ctrl+O	Expand/collapse the most recent tool call's output
Ctrl+R	Session picker (persisted across turns)
Ctrl+A	Same dispatch as typing /agents
Ctrl+W / Alt+Backspace	Delete the previous word
Up (empty input)	Recall the last message you sent
Page Up / Page Down	Scroll the transcript a screenful
Tab	Cycle panes
Ctrl+Tab / Ctrl+Shift+Tab	Cycle sessions
F10	Open the menu bar
y / n / a	Answer a permission prompt: once / refuse / always

Ctrl+P, Ctrl+O, Ctrl+A, Ctrl+W and Ctrl+C always belong to the chat content model — the shell never claims them, in any pane, so hosting chat inside the shell cannot silently steal a binding.

Mouse

Mouse mode is on by default (SUGARCRUSH_DISABLE_MOUSE=1 turns it off). Zones are registered during the render pass, so clicks land on what you see: wheel scrolls the transcript, clicking a tool call expands/collapses it, clicking a session tab or a pane label switches to it, clicking a palette/picker row selects it, and clicking the menu bar opens a menu. Click-vs-drag is discriminated so a text-selection drag does not fire the zone underneath it.

Slash commands

/agents /agent /bg /background /fork /branch /compact /mcp /memory /rename /rewind /sessions /share /theme /workflow /exit (/quit) — plus any file-based custom command found on disk. Typing / opens a live popup of the matches.

New session, Switch model and Open docs are palette-only actions (Ctrl+P) — they have no slash spelling, so CommandRegistry keeps them out of the / popup.

/bg really does run the work: it dispatches onto a BackgroundSupervisor that bin/sugarcrush constructs per launch, and the result comes back into the transcript. /fork branches the current session.

What you see while a turn runs

Tool calls stream into the transcript as they happen — the forked child emits lifecycle events rather than buffering until the turn ends — each with a human-readable description and the command it actually ran, then a running→done transition. Edit/Write results render a real unified diff. A no-op edit reports as a no-op instead of success. Denied and interrupted calls get their own visual state. Tool results that carry images are labelled and rendered inline via candy-mosaic. Successful tool bodies are hidden by default (Ctrl+O or a click opens them). Context usage shows as both a token count and a percentage.

Sessions get a name automatically: after the first exchange a cheap small-model backend (supplied separately from the conversation backend, so naming never costs a second tool-capable agent turn) generates a title, which is what /sessions, the tab strip and Ctrl+R list.

Providers

SugarCraft\Crush\Providers\ProviderInterface is the single LLM abstraction (capability introspection, batch + \Generator streaming, function calling, embeddings, per-model cost). Build one directly or from config via ProviderFactory (which resolves ${VAR} / ${VAR:-default} from the environment):

use SugarCraft\Crush\Providers\ProviderFactory;

$factory  = new ProviderFactory();
$provider = $factory->create(['type' => 'openai', 'apiKey' => '${OPENAI_API_KEY}', 'model' => 'gpt-4o']);

Provider	Type key	Notes
OpenAI	openai	openai-php/client; function calling, embeddings, cost table
Anthropic	anthropic	real Messages API (/v1/messages, x-api-key)
Claude Code CLI	claude-code	drives the claude binary headless; native cost; JSON schema
SGLang	sglang	OpenAI-compatible self-hosted endpoints (Guzzle)
AWS Bedrock	bedrock	Converse API via aws/aws-sdk-php; per-model pricing
GCP Vertex	vertex	Anthropic-on-Vertex via an injectable predictor seam
Custom	custom	any OpenAI-compatible HTTP endpoint
Echo	—	EchoProvider: offline, echoes the last turn; default + tests

The sglang type accepts an optional toolCallParser key: 'openai' (the default — read the server's parsed tool_calls[] array) or 'minimax-xml-fallback' (same, but when the array is absent, recover MiniMax's raw <tool_call> XML out of the message content). Switch it only if your SGLang deployment was launched without --tool-call-parser, which leaves the model's tool-call XML unparsed in the content. Note this currently applies to the batch complete() path only — the streaming path reassembles tool calls itself and does not yet consult the setting.

The agent loop

EngineBackend bridges the chat-shell Backend seam to the engine. Each user turn runs a bounded agentic loop: call the provider through the Runtime, execute any tool calls through the hook gate, feed the results back, and repeat until the model answers without calling tools — or a maxSteps ceiling is hit.

use SugarCraft\Crush\Backend\EngineBackend;
use SugarCraft\Crush\Hooks\{HookManager, HookRegistry};
use SugarCraft\Crush\Tools\BuiltIn\{Bash, Read, Edit, Glob, Grep, WebFetch};

$hooks = new HookManager(new HookRegistry());
$hooks->registerBuiltIns();                       // audit + confirm-rm + protect-files

$backend = (EngineBackend::new($provider, 'gpt-4o'))
    ->withTools([new Bash(), new Read(), new Edit(), new Glob(), new Grep(), new WebFetch()])
    ->withHooks($hooks);

(new Program(new Chat(backend: $backend)))->run();

Capabilities

• Tools — Tools\BuiltIn\*: Bash, Read, Edit, Glob, Grep, WebFetch, Doctor (a capability probe the model can call to report what this build/deployment actually supports), and Skill (level 2 of the progressive-disclosure design below). Implement Tools\Tool for your own.
• Hooks — Hooks\*: pre/post-tool-use guards (allow / deny / modify the input). Built-ins: AuditHook, ConfirmRemoveHook, ProtectFilesHook. YAML config and external ScriptHook supported.
• Permission modes — Permissions\*: PermissionGate enforces one of six PermissionModes (default, accept-edits, plan, auto, dont-ask, bypass-permissions) per tool call, with a mode-independent rm-rf circuit breaker and a fail-closed auto classifier when no SafetyClassifier is configured.
• Skills — Skills\*: frontmatter SKILL.md files inject prompt context, matched by keyword/path. Discovered from built-ins (src/Skills/BuiltIn/), ~/.sugar-crush/skills, and <project>/.sugar-crush/skills (project wins). Ships 12 built-ins spanning language/framework conventions (php-best-practices, laravel-best-practices, symfony-best-practices), workflow (testing-strategies, api-design, explore-codebase, worktree-workflow, mcp-authoring, matchups-sync) and the original four (security-audit, phpunit-master, composer-wizard). disable-model-invocation, user-invocable, and context: fork frontmatter flags are enforced, not decorative — a fork-context skill runs through AgentWorkerPool as an isolated sub-agent. Loading is progressive: the system prompt carries only each skill's name + description, and the model pulls the full SKILL.md body through the Skill tool when it decides one is relevant. Path-scoped skills self-announce — the first time Read/Edit/Glob touches a file a skill's paths: covers, that skill is surfaced (once per session, via one shared announce-set across the three tools). Skills authored for other CLIs (Claude Code, opencode) are imported rather than ignored, and the picker shows a provenance badge for where each one came from.
• Agents — Agents\*: 6 sub-agent presets (coder/reviewer/debugger/architect/tester/devops) with their own model, tools, skills, and a streaming lifecycle, dispatched through AgentWorkerPool (pcntl_fork-based, with a synchronous fallback + warning when pcntl is unavailable).
• Teams & worktrees — Agents\{Team,TeamManager,Teammate,TaskList,Mailbox}: a lead agent spawns a capped team of teammates that atomically claim TaskList tasks (SQLite flock-backed, contention-tested) and exchange append-only JSON-lines mailbox messages. Agents\{WorktreeConfig,WorktreeManager,PathJail} give each teammate an isolated git worktree (.worktreeinclude-aware, swept for staleness) sandboxed by a path jail.
• Workflows — Workflows\*: WorkflowBuilder/WorkflowRegistry/WorkflowEngine run multi-stage agent pipelines — sequential stage(), fan-out parallel(), chained pipeline(), and task-then-verifier withVerification() — defined as PHP DSL files or YAML (WorkflowRegistry::loadYaml()). SIGINT/SIGTERM during run() captures a real pause file for later resumption at stage granularity. See examples/workflows/lint-then-fix.yaml for a runnable YAML example and workflows/deep-research.php for the PHP DSL form.
• MCP — MCP\*: multi-server client (stdio + HTTP, .mcp.json, ${VAR} interpolation) and stdio/HTTP servers to host your own tools. Per-agent-preset mcpServers allowlists are enforced by McpClient against McpRouter, not just decorative config.
• Sessions — Session\SessionStore: SQLite (WAL) persistence of sessions/messages/tool-calls with FK-enforced cascade and age-based pruning.
• Tokens & export — Util\TokenTracker (token + cost accumulation) and Util\Exporter (Markdown / JSON / text transcripts).
• Messages — typed Messages\{System,User,Assistant,ToolResult}Message; UserMessage carries file/image attachments; AssistantMessage carries tool calls + reasoning.
• Context files — CLAUDE.md/AGENTS.md at the project root are loaded into the system prompt, with @import expansion (cycle- and traversal-guarded, and de-duplicated so an imported doc is not injected twice). Forced instructions come from user config. An EnvironmentBlock (cwd, platform, git state, date) is prepended so the model is not guessing at its surroundings.
• Permission prompts — a blocking request/reply flow (HookResult::ask() → PermissionRequestMsg/PermissionReplyMsg) rendered as a Veil modal over the transcript; the answer settles the paused tool call rather than being advisory.

Architecture

SugarCrush keeps the proven sugar-crush chassis (the Chat candy-core Model, buffer-diff Renderer) and runs the ported engine behind it. The interactive binary boots the pane shell that hosts that chassis:

bin/sugarcrush
  └─ Bootstrap::app()
       └─ Program → App (root candy-core Model: menu bar, pane focus, session tabs)
            ├─ Tui\Renderer → ChatPane ─┐
            │                            └→ Renderer (the live buffer-diff chat renderer)
            └─ Chat (Model: input, scrollback, inFlight gate, permissions, zones)
                 └─ Backend  ── EchoBackend / CommandBackend (simple)
                             └─ EngineBackend (agent loop, emits tool-lifecycle events)
                                  └─ Runtime → ProviderInterface  (+ Tools · Hooks · Skills via App)

App plays two roles that are easy to confuse: it is the engine's state object (Runtime::run(App $app, …) and EngineBackend both take it, carrying tools/hooks/skills) and the root TUI Model the pane shell renders. Chat is untouched by the shell — it is still a standalone Model you can run directly with new Program(new Chat(...)).

The chassis speaks the root Message value object; the engine speaks the typed Messages\* hierarchy; EngineBackend converts at the seam.

Limitations

Things that are genuinely not finished, stated plainly rather than left for you to discover:

• SglangProvider's toolCallParser applies to the batch complete() path only. The streaming path reassembles tool calls itself and does not consult the setting.
• Five shell commands are still inert: GroupInputCmd, CancelAgentCmd, ResumeAgentCmd, StopAllAgentsCmd, QuitAgentViewCmd. The first has no counterpart in the live app; the agent four would need to reach into a worker pool the shell does not hold. Their pane/selection half is applied — only the action half is missing.
• Workflow resume granularity is per whole stage. An interrupted parallel sub-stage cannot be resumed with partial credit.
• pcntl is required for real parallelism. Without it AgentWorkerPool falls back to sequential execution and logs a one-time visible warning rather than pretending to fan out.
• Providers are unit-tested against mocked transports. No test in this suite makes a live API call, so wire-format drift at a real endpoint is caught by /doctor and by using it, not by CI.
• The Doctor tool reports capabilities, it does not repair them.

Custom provider

use SugarCraft\Crush\Providers\{ProviderInterface, CompleteRequest, CompleteResponse, EmbeddingsRequest, EmbeddingsResponse};

final class MyProvider implements ProviderInterface
{
    public function name(): string { return 'mine'; }
    public function supportsStreaming(): bool { return false; }
    public function supportsFunctionCalling(): bool { return true; }
    public function supportsVision(): bool { return false; }
    public function supportsJsonSchema(): bool { return false; }
    public function contextWindow(): int { return 128_000; }
    public function costPer1kTokens(string $model, string $direction): float { return 0.0; }
    public function complete(CompleteRequest $r): CompleteResponse { /* ... */ }
    public function completeStream(CompleteRequest $r): \Generator { /* yield CompleteResponse chunks */ }
    public function embeddings(EmbeddingsRequest $r): EmbeddingsResponse { /* ... */ }
}

Tests

cd sugar-crush && composer install && vendor/bin/phpunit

4,337 tests / 12,587 assertions (0 failures, 0 errors). Coverage spans every subsystem: typed messages + attachments, the 6 built-in tools, all 7 providers (unit-tested with mocked transports — no live calls), the hook framework, permission-mode gating (incl. pcntl_fork concurrency stress tests for atomic task claiming), skills discovery + flag enforcement, sub-agents/teams/worktrees, workflow execution (sequential/parallel/pipeline/verification, PHP + YAML loading), the MCP client/servers (incl. per-agent routing enforcement), the SQLite store, token tracking, export, the TUI components, the Runtime orchestration (streaming accumulation, tool-result correlation, MODIFY hooks), the shell-out CommandBackend / StreamingCommandBackend, and the EngineBackend agentic loop (incl. the maxSteps guard).

A dedicated tests/Integration/ tier asserts reachability rather than behaviour: that the session store, session tabs, background sessions, the skills subsystem, mouse mode, the environment block and root context-file loading are actually reached from bin/sugarcrush → Bootstrap::app(), not merely implemented somewhere in src/. That tier exists because the audit recorded in the monorepo root's crush_code_update.md found well-tested subsystems that no real run could ever touch.

See CHANGELOG.md for how the suite got here.