feat: basic usage

.gitignore

@@ -1 +1,2 @@
 target/*
+.loop/

Cargo.toml

@@ -2,6 +2,7 @@
 name = "yoke"
 version = "0.1.0"
 edition = "2024"
+description = "LLM automation loop harness"
 
 [[bin]]
 name = "yoke"

loop/ci.conf

@@ -1,17 +0,0 @@
-# CI loop configuration
-
-# Claude binary path
-claude      claude
-
-# Max lines of guard output to keep
-max-tail    200
-
-# Scope rules (diff boundary enforcement)
-# Most-specific (longest) prefix wins.
-allow       .
-allow       src/
-allow       loop/guards/
-add-only    tests/
-
-# Guards (run in order, fail-fast)
-guard       cargo check -p yoke

loop/plan.md

@@ -1,145 +0,0 @@
-Richer Stdout Display
-
-Deliverable: Improve the NDJSON stream filter so the operator can follow Claude's
-full reasoning. Currently assistant text is truncated to 3 lines / 120 chars and
-many event types are silently dropped. No new crates — pure std only.
-
----
-Context
-
-The stream filter in src/stream.rs reads Claude's NDJSON output and formats it
-as ANSI-colored terminal output. Current problems:
-
-1. Assistant text is hard-capped at 3 lines and 120 chars per line. This cuts off
-   Claude's thinking and explanations — the operator has no idea what it's doing.
-
-2. The `stream_event` wrapper type (the majority of NDJSON lines) is silently
-   dropped. These carry `content_block_delta` events with partial text and input
-   JSON, which are useful for streaming progress.
-
-3. Tool results are invisible — the `user` event type (which carries tool_result
-   content) is never matched.
-
-Goal: Show Claude's full text output, stream partial text deltas as they arrive,
-and show a brief summary of tool results.
-
----
-Implementation Stages
-
-
-Stage A: Remove text truncation, show full assistant output
-
-Objective: Stop cutting off assistant text so the operator sees everything.
-
-src/stream.rs — in the `Some("assistant")` branch, the text display path:
-
-  Current code truncates:
-    for text_line in trimmed.lines().take(3) {
-        let truncated = if text_line.len() > 120 { &text_line[..120] } else { text_line };
-        println!("{}  {}{}", DIM, truncated, RESET);
-    }
-
-  Change to print all lines with no length limit:
-    for text_line in trimmed.lines() {
-        println!("{}  {}{}", DIM, text_line, RESET);
-    }
-
-Verify: cargo check -p yoke passes.
-
-
-Stage B: Display streaming text deltas
-
-Objective: Show `content_block_delta` events so text streams to the terminal
-as Claude thinks, rather than appearing only in the final `assistant` message.
-
-src/stream.rs — add a `Some("stream_event")` match arm. These lines wrap inner
-events in a `{"type":"stream_event","event":{...}}` envelope.
-
-The inner event types to handle:
-
-  `content_block_delta` with `"text_delta"`:
-    The delta has `{"type":"text_delta","text":"..."}`. Extract the `text` field
-    from the inner delta and print it inline (no newline — use `print!` not
-    `println!`) so streaming text accumulates naturally:
-      print!("{}{}{}", DIM, text, RESET);
-    Flush stdout after each delta.
-
-  `content_block_delta` with `"input_json_delta"`:
-    These are partial tool input being streamed. Skip these silently — the
-    complete tool call will be shown when the full `assistant` event arrives.
-
-  `content_block_start`:
-    If it contains `"tool_use"`, print nothing (the full assistant event will
-    show the tool call). If it contains `"text"`, print a newline to start
-    a fresh line for streaming text.
-
-  `content_block_stop`:
-    Print a newline to terminate any streaming text on the current line.
-
-  `message_start`, `message_delta`, `message_stop`:
-    Skip silently — these are bookkeeping.
-
-To detect the inner event type, use extract_str on the line for the `"type"`
-field inside `"event"`. Since the line has a top-level `"type":"stream_event"`
-and an inner `"type":"content_block_delta"` (etc.), and extract_str now retries
-past value matches, you can search for the inner type by looking for specific
-strings:
-  - line.contains("\"content_block_delta\"") → delta handling
-  - line.contains("\"content_block_start\"") → start handling
-  - line.contains("\"content_block_stop\"") → stop handling
-  - Otherwise → skip
-
-For text_delta extraction: search for `"text_delta"` in the line, then extract
-the `"text"` field. Since the line may have multiple `"text"` keys (the delta
-type and the actual text content), extract_str's retry logic will handle this.
-
-Important: flush stdout after each print! call so streaming text appears
-immediately:
-  use std::io::stdout;
-  stdout().flush().ok();
-
-Verify: cargo check -p yoke passes.
-
-
-Stage C: Show tool result summaries
-
-Objective: When Claude reads a file or runs a command, show a brief summary of
-the tool result so the operator knows what happened.
-
-src/stream.rs — add a `Some("user")` match arm. User events carry tool results
-in the format:
-  {"type":"user","message":{"role":"user","content":[{"tool_use_id":"...","type":"tool_result","content":"..."}]}}
-
-For tool results:
-  - Extract the tool_use_id (not critical but nice)
-  - Check if the line contains `"tool_result"`
-  - Show a brief dim summary: the first 120 chars of the content, or just
-    "[tool result]" if content can't be extracted
-  - Format: `println!("{}  ← result ({}b){}", DIM, content_len, RESET)`
-    where content_len is the approximate length of the result content
-
-Keep it simple — just indicate a result came back and roughly how big it was.
-The exact content is less important than knowing it happened.
-
-Verify: cargo check -p yoke passes.
-
----
-Files to modify
-
-| File | Change |
-|------|--------|
-| src/stream.rs | Remove truncation, add stream_event + user event handling |
-
----
-Constraints
-
-No external crates. Edition 2024. Pure std only.
-Only modify src/stream.rs.
-
----
-Success Criteria
-
-1. cargo check -p yoke passes
-2. Assistant text displays in full — no line count or character limit
-3. Streaming text deltas appear as Claude thinks
-4. Tool results show a brief acknowledgment line

loop/protocol.md

@@ -1,64 +0,0 @@
-# Protocol: Automated CI Loop
-
-You are operating inside an automated loop — not a conversation. A bash script launched you, and will run guard checks after you exit. You do not interact with a human during this session.
-
-## Files
-
-| File | You can | Purpose |
-|------|---------|---------|
-| `loop/protocol.md` | read | This document. Your instructions. |
-| `loop/plan.md` | read | The feature plan. Stages to implement. |
-| `loop/notes.md` | read + write | Your scratchpad. Persists across iterations. |
-| `loop/guard-results.md` | read | Guard results from the last iteration. |
-| `loop/ci.conf` | read | Loop configuration. Scope rules, guards, settings. |
-
-All paths are relative to the repository root.
-
-## Per-Iteration Steps
-
-1. **Read the plan** (`loop/plan.md`). Understand the full feature and all its stages.
-2. **Read your notes** (`loop/notes.md`). This is your memory across iterations — check which stage you are on, what you tried, and what you learned.
-3. **Read guard results** (`loop/guard-results.md`). If it exists and is non-empty, the previous iteration's guards ran. Look for failures. If a guard failed, your priority is fixing the failure before advancing to a new stage.
-4. **Determine task**. Either fix a guard failure (if any) or implement the next incomplete stage from the plan.
-5. **Implement**. Make the code changes for exactly one stage. Work in the repository's working tree.
-6. **Update notes**. Write to `loop/notes.md`:
-   - Which stage you just worked on
-   - What you changed and why
-   - Any issues or observations for your future self
-   - A `STATUS` line at the **top** of the file (see below)
-7. **Exit**. Stop. Do not loop — the outer script handles iteration.
-
-## STATUS Signaling
-
-The first line of `loop/notes.md` must be one of:
-
-- `STATUS: IN_PROGRESS` — You have more work to do (stages remain, or you expect guard failures).
-- `STATUS: DONE` — All stages in the plan are implemented and you believe guards will pass.
-
-The outer loop reads this line. It exits only when `STATUS: DONE` **and** all guards pass.
-
-## What the Guards Check
-
-After you exit, the outer loop runs guards defined in `loop/ci.conf`.
-
-1. **Diff boundary check** — Always runs first. Verifies every file you changed
-   or created is within the scope rules defined in `loop/ci.conf`. The rules:
-   - `allow PREFIX` — anything goes: add, modify, delete.
-   - `add-only PREFIX` — may only add lines; no removing existing lines.
-   - `no-modify PREFIX` — zero modifications allowed.
-   - No matching rule — change is denied.
-   - Most-specific (longest) prefix wins when rules overlap.
-   If the boundary check fails, all subsequent guards are skipped.
-2. **Configured guards** — Read the `guard` lines in `loop/ci.conf` to see
-   what commands run. Guards execute in order, fail-fast (first failure skips
-   the rest).
-
-You may run any commands you find useful during implementation.
-
-## Rules
-
-- **No git operations.** Do not commit, push, branch, or modify git config. The outer loop owns git.
-- **Do not modify `protocol.md`, `plan.md`, or `scope.conf`.** These are read-only to you.
-- **One stage per iteration.** Implement a single stage, update notes, and exit. Do not attempt multiple stages.
-- **Retry discipline.** If you have failed on the same issue for 3 consecutive iterations (check your notes), try a fundamentally different approach. Do not repeat the same fix.
-- **Be concise in notes.** Future-you needs signal, not noise. Record what matters: what stage, what changed, what broke, what to try next.

src/config.rs

@@ -19,8 +19,11 @@ pub struct Config {
     pub claude_bin: String,
     pub max_tail: usize,
     pub log_dir: Option<String>,
+    pub image: Option<String>,
     pub scope_rules: Vec<ScopeRule>,
     pub guards: Vec<String>,
+    pub runner: String,
+    pub judge: Option<String>,
 }
 
 impl Config {
@@ -31,8 +34,11 @@ impl Config {
         let mut claude_bin = String::from("claude");
         let mut max_tail: usize = 200;
         let mut log_dir: Option<String> = None;
+        let mut image: Option<String> = None;
         let mut scope_rules = Vec::new();
         let mut guards = Vec::new();
+        let mut runner = String::from("loop");
+        let mut judge: Option<String> = None;
 
         for (line_num, raw_line) in content.lines().enumerate() {
             // Strip comments
@@ -73,6 +79,9 @@ impl Config {
                 "log-dir" => {
                     log_dir = Some(value.to_string());
                 }
+                "image" => {
+                    image = Some(value.to_string());
+                }
                 "allow" => scope_rules.push(ScopeRule {
                     tag: ScopeTag::Allow,
                     prefix: value.to_string(),
@@ -86,6 +95,8 @@ impl Config {
                     prefix: value.to_string(),
                 }),
                 "guard" => guards.push(value.to_string()),
+                "runner" => runner = value.to_string(),
+                "judge" => judge = Some(value.to_string()),
                 other => {
                     return Err(format!(
                         "{}:{}: unknown directive '{}'",
@@ -101,8 +112,11 @@ impl Config {
             claude_bin,
             max_tail,
             log_dir,
+            image,
             scope_rules,
             guards,
+            runner,
+            judge,
         })
     }
 

src/main.rs

@@ -11,11 +11,151 @@ use std::process::{self, Child, Command, Stdio};
 
 use config::Config;
 
-const CONF_PATH: &str = "loop/ci.conf";
+const CONF_PATH: &str = ".loop/guard.conf";
-const NOTES_PATH: &str = "loop/notes.md";
+const NOTES_PATH: &str = ".loop/notes.md";
-const GUARD_RESULTS_PATH: &str = "loop/guard-results.md";
+const GUARD_RESULTS_PATH: &str = ".loop/guard-results.md";
-const PROTOCOL_PATH: &str = "loop/protocol.md";
+const PROTOCOL_PATH: &str = ".loop/protocol.md";
-const PLAN_PATH: &str = "loop/plan.md";
+const PLAN_PATH: &str = ".loop/plan.md";
+const TASK_PATH: &str = ".loop/task.md";
+const JUDGE_PATH: &str = ".loop/judge.md";
+const VERDICT_PATH: &str = ".loop/verdict.md";
+
+const DEFAULT_PROTOCOL: &str = r#"# Protocol: Automated CI Loop
+
+You are operating inside an automated loop — not a conversation. A bash script launched you, and will run guard checks after you exit. You do not interact with a human during this session.
+
+## Files
+
+| File | You can | Purpose |
+|------|---------|---------|
+| `.loop/protocol.md` | read | This document. Your instructions. |
+| `.loop/plan.md` | read | The feature plan. Stages to implement. |
+| `.loop/notes.md` | read + write | Your scratchpad. Persists across iterations. |
+| `.loop/guard-results.md` | read | Guard results from the last iteration. |
+| `.loop/guard.conf` | read | Loop configuration. Scope rules, guards, settings. |
+
+All paths are relative to the repository root.
+
+## Per-Iteration Steps
+
+1. **Read the plan** (`.loop/plan.md`). Understand the full feature and all its stages.
+2. **Read your notes** (`.loop/notes.md`). This is your memory across iterations — check which stage you are on, what you tried, and what you learned.
+3. **Read guard results** (`.loop/guard-results.md`). If it exists and is non-empty, the previous iteration's guards ran. Look for failures. If a guard failed, your priority is fixing the failure before advancing to a new stage.
+4. **Determine task**. Either fix a guard failure (if any) or implement the next incomplete stage from the plan.
+5. **Implement**. Make the code changes for exactly one stage. Work in the repository's working tree.
+6. **Update notes**. Write to `.loop/notes.md`:
+   - Which stage you just worked on
+   - What you changed and why
+   - Any issues or observations for your future self
+   - A `STATUS` line at the **top** of the file (see below)
+7. **Exit**. Stop. Do not loop — the outer script handles iteration.
+
+## STATUS Signaling
+
+The first line of `.loop/notes.md` must be one of:
+
+- `STATUS: IN_PROGRESS` — You have more work to do (stages remain, or you expect guard failures).
+- `STATUS: DONE` — All stages in the plan are implemented and you believe guards will pass.
+
+The outer loop reads this line. It exits only when `STATUS: DONE` **and** all guards pass.
+
+## What the Guards Check
+
+After you exit, the outer loop runs guards defined in `.loop/guard.conf`.
+
+1. **Diff boundary check** — Always runs first. Verifies every file you changed
+   or created is within the scope rules defined in `.loop/guard.conf`. The rules:
+   - `allow PREFIX` — anything goes: add, modify, delete.
+   - `add-only PREFIX` — may only add lines; no removing existing lines.
+   - `no-modify PREFIX` — zero modifications allowed.
+   - No matching rule — change is denied.
+   - Most-specific (longest) prefix wins when rules overlap.
+   If the boundary check fails, all subsequent guards are skipped.
+2. **Configured guards** — Read the `guard` lines in `.loop/guard.conf` to see
+   what commands run. Guards execute in order, fail-fast (first failure skips
+   the rest).
+
+You may run any commands you find useful during implementation.
+
+## Rules
+
+- **No git operations.** Do not commit, push, branch, or modify git config. The outer loop owns git.
+- **Do not modify `protocol.md`, `plan.md`, or `guard.conf`.** These are read-only to you.
+- **One stage per iteration.** Implement a single stage, update notes, and exit. Do not attempt multiple stages.
+- **Retry discipline.** If you have failed on the same issue for 3 consecutive iterations (check your notes), try a fundamentally different approach. Do not repeat the same fix.
+- **Be concise in notes.** Future-you needs signal, not noise. Record what matters: what stage, what changed, what broke, what to try next.
+"#;
+
+const DEFAULT_GUARD_CONF: &str = "\
+# Guard configuration
+
+claude      claude
+image       claude-code-sandbox:latest
+
+# Max lines of guard output to keep
+max-tail    200
+
+# Scope rules (diff boundary enforcement)
+# Tags: allow (any change), add-only (new lines only), no-modify (no changes)
+# Most-specific (longest) prefix wins.
+allow       .
+
+# Guards (run in order, fail-fast)
+guard       cargo check
+";
+
+const DEFAULT_BRUTE_PROTOCOL: &str = r#"# Brute Protocol
+
+You are a worker in an automated brute-force loop. Your single goal is described
+in `.loop/task.md`. You iterate until a blind judge (a separate Claude instance
+with zero implementation context) confirms the task is complete.
+
+## Files
+
+| File | Access | Purpose |
+|---|---|---|
+| `.loop/protocol.md` | read | These instructions. |
+| `.loop/task.md` | read | The goal. |
+| `.loop/judge.md` | read | What the judge will test. Study this. |
+| `.loop/notes.md` | read+write | Your scratchpad across iterations. |
+| `.loop/verdict.md` | read | The judge's last verdict. |
+| `.loop/ci.conf` | read | Configuration. |
+
+## Per-Iteration
+
+1. Read `.loop/task.md` — understand the goal.
+2. Read `.loop/notes.md` — recall what you have tried.
+3. Read `.loop/verdict.md` — the judge's exact complaints from last iteration.
+4. Make changes to accomplish the task.
+5. Update `.loop/notes.md` with what you changed and why.
+6. Exit — the harness runs guards then the judge.
+
+## Rules
+
+- No git operations.
+- Do not modify protocol.md, task.md, judge.md, or ci.conf.
+- Study judge.md — knowing the test helps you pass it.
+- The judge's feedback is ground truth. Fix what they say is broken.
+- After 3 similar verdicts, try a fundamentally different approach.
+- Be concise in notes.
+"#;
+
+const DEFAULT_BRUTE_CONF: &str = "\
+# Brute runner configuration
+
+runner      brute
+claude      claude
+max-tail    200
+
+allow       .
+
+# Guards (run before judge, fail-fast)
+guard       cargo check
+
+# Judge — a fresh Claude that verifies the feature blind.
+# The value is the Claude binary (same format as the claude directive).
+judge       claude
+";
 
 /// Files that Claude must not be allowed to permanently alter.
 const PROTECTED_FILES: &[&str] = &[PROTOCOL_PATH, PLAN_PATH, CONF_PATH];
@@ -30,31 +170,39 @@ const YELLOW: &str = "\x1b[33m";
 const DIM: &str = "\x1b[2m";
 
 fn log(msg: &str) {
-    eprintln!("{}{}[ci]{} {}", BOLD, CYAN, RESET, msg);
+    eprintln!("{}{}[yoke]{} {}", BOLD, CYAN, RESET, msg);
 }
 
 fn log_error(msg: &str) {
-    eprintln!("{}{}[ci] ERROR:{} {}", BOLD, RED, RESET, msg);
+    eprintln!("{}{}[yoke] ERROR:{} {}", BOLD, RED, RESET, msg);
 }
 
 fn print_usage() {
     eprintln!(
-        "{}{}ci{} — LLM loop harness{}",
+        "{}{}yoke{} — LLM loop harness{}",
         BOLD, CYAN, RESET, RESET
     );
     eprintln!();
     eprintln!(
-        "{}USAGE:{} ci <command> [options]",
+        "{}USAGE:{} yoke <command> [options]",
         BOLD, RESET
     );
     eprintln!();
     eprintln!("{}COMMANDS:{}", BOLD, RESET);
     eprintln!(
-        "  {}run{}              Launch the CI loop (invoke Claude, run guards, iterate)",
+        "  {}init{}                    Initialize .loop/ directory with default files",
         BOLD, RESET
     );
     eprintln!(
-        "  {}run --dry-run{}    Single iteration: boundary check + guards only, no Claude",
+        "  {}init --runner <type>{}    Initialize for a specific runner (loop or brute)",
+        BOLD, RESET
+    );
+    eprintln!(
+        "  {}run{}                     Launch the CI loop (invoke Claude, run guards, iterate)",
+        BOLD, RESET
+    );
+    eprintln!(
+        "  {}run --dry-run{}           Single iteration: boundary check + guards only, no Claude",
         BOLD, RESET
     );
     eprintln!();
@@ -73,12 +221,12 @@ fn print_usage() {
 
 fn print_run_help() {
     eprintln!(
-        "{}{}ci run{} — execute the CI loop{}",
+        "{}{}yoke run{} — execute the CI loop{}",
         BOLD, CYAN, RESET, RESET
     );
     eprintln!();
     eprintln!(
-        "{}USAGE:{} ci run [--dry-run]",
+        "{}USAGE:{} yoke run [--dry-run]",
         BOLD, RESET
     );
     eprintln!();
@@ -86,15 +234,54 @@ fn print_run_help() {
     eprintln!("  --dry-run    Run one iteration without invoking Claude");
     eprintln!("               (boundary check + configured guards only)");
     eprintln!();
-    eprintln!("{}WORKFLOW:{}", BOLD, RESET);
+    eprintln!("{}RUNNER TYPES:{}", BOLD, RESET);
+    eprintln!("  The runner type is determined by the 'runner' directive in {}.", CONF_PATH);
+    eprintln!("  {}loop{}    (default) Staged plan runner — iterates until STATUS: DONE and guards pass.", BOLD, RESET);
+    eprintln!("  {}brute{}   Blind-judge runner — iterates until an independent judge says PASS.", BOLD, RESET);
+    eprintln!();
+    eprintln!("{}WORKFLOW (loop):{}", BOLD, RESET);
     eprintln!("  1. Load config from {}", CONF_PATH);
-    eprintln!("  2. Backup protected files (protocol.md, plan.md, ci.conf)");
+    eprintln!("  2. Backup protected files (protocol.md, plan.md, guard.conf)");
     eprintln!("  3. Per iteration:");
     eprintln!("     a. Restore protected files");
     eprintln!("     b. Invoke Claude with stream-json output");
     eprintln!("     c. Run diff boundary check");
     eprintln!("     d. Run configured guard commands");
     eprintln!("  4. Exit when STATUS: DONE and all guards pass");
+    eprintln!();
+    eprintln!("{}WORKFLOW (brute):{}", BOLD, RESET);
+    eprintln!("  1. Load config from {}", CONF_PATH);
+    eprintln!("  2. Backup protected files (protocol.md, task.md, judge.md, ci.conf)");
+    eprintln!("  3. Per iteration:");
+    eprintln!("     a. Restore protected files, clear verdict");
+    eprintln!("     b. Invoke worker Claude");
+    eprintln!("     c. Run diff boundary check + configured guards");
+    eprintln!("     d. If guards pass, invoke judge (fresh Claude, zero context)");
+    eprintln!("  4. Exit when judge returns VERDICT: PASS");
+}
+
+fn print_init_help() {
+    eprintln!(
+        "{}{}yoke init{} — initialize .loop/ directory{}",
+        BOLD, CYAN, RESET, RESET
+    );
+    eprintln!();
+    eprintln!(
+        "{}USAGE:{} yoke init [--runner <type>]",
+        BOLD, RESET
+    );
+    eprintln!();
+    eprintln!("{}OPTIONS:{}", BOLD, RESET);
+    eprintln!("  --runner <type>  Runner type: loop (default) or brute");
+    eprintln!();
+    eprintln!("{}RUNNER TYPES:{}", BOLD, RESET);
+    eprintln!("  {}loop{}   (default) Staged plan runner. Creates:", BOLD, RESET);
+    eprintln!("           ci.conf, protocol.md, plan.md, notes.md, guard-results.md");
+    eprintln!();
+    eprintln!("  {}brute{}  Blind-judge runner. Creates:", BOLD, RESET);
+    eprintln!("           ci.conf, protocol.md, task.md, judge.md, notes.md, verdict.md");
+    eprintln!();
+    eprintln!("Existing files are never overwritten.");
 }
 
 /// Holds loop state and cleans up on drop.
@@ -124,6 +311,7 @@ impl Drop for LoopRunner {
             let _ = child.kill();
             let _ = child.wait();
         }
+        signal::set_child_pid(0);
         // Remove backup directory
         let _ = fs::remove_dir_all(&self.backup_dir);
     }
@@ -150,7 +338,7 @@ fn preflight() {
 
 /// Copy protected files to a temp directory. Returns the backup path.
 fn backup_protected() -> PathBuf {
-    let backup_dir = std::env::temp_dir().join(format!("ci-backup-{}", process::id()));
+    let backup_dir = std::env::temp_dir().join(format!("yoke-backup-{}", process::id()));
     if let Err(e) = fs::create_dir_all(&backup_dir) {
         log_error(&format!("failed to create backup dir: {}", e));
         process::exit(1);
@@ -176,7 +364,7 @@ fn restore_protected(backup_dir: &Path) {
         if backup_file.exists() {
             if let Err(e) = fs::copy(&backup_file, path) {
                 eprintln!(
-                    "{}{}[ci] WARNING:{} failed to restore {}: {}",
+                    "{}{}[yoke] WARNING:{} failed to restore {}: {}",
                     BOLD, YELLOW, RESET, path, e
                 );
             }
@@ -196,31 +384,95 @@ fn is_done() -> bool {
 /// The Child is stored in `runner` for cleanup-on-drop safety.
 /// Returns the child's exit status success.
 fn invoke_claude(runner: &mut LoopRunner, config: &Config, iteration: u32) -> bool {
-    log(&format!("Launching Claude (iteration {})...", iteration));
+    let claude_args = [
+        "--verbose",
+        "--output-format",
+        "stream-json",
+        "--include-partial-messages",
+        "--dangerously-skip-permissions",
+        "-p",
+        "Read .loop/protocol.md and follow its instructions.",
+    ];
 
-    let mut child = match Command::new(&config.claude_bin)
+    let mut cmd = if let Some(ref image) = config.image {
-        .args([
+        log(&format!(
-            "--verbose",
+            "Launching Claude in container (iteration {})...",
-            "--output-format",
+            iteration
-            "stream-json",
+        ));
-            "--include-partial-messages",
+
-            "-p",
+        let workdir = std::env::current_dir()
-            "Read loop/protocol.md and follow its instructions.",
+            .unwrap_or_else(|_| PathBuf::from("."))
-        ])
+            .to_string_lossy()
+            .to_string();
+
+        let mut c = Command::new("docker");
+        c.args([
+            "run",
+            "--rm",
+            "-i",
+            "--network=host",
+            "--cap-add=NET_ADMIN",
+            "--cap-add=NET_RAW",
+        ]);
+
+        // Bind-mount the workspace
+        c.arg("-v").arg(format!("{}:/workspace", workdir));
+        c.arg("-w").arg("/workspace");
+
+        // Forward all CLAUDE_* and ANTHROPIC_* env vars
+        for (key, val) in std::env::vars() {
+            if key.starts_with("CLAUDE_") || key.starts_with("ANTHROPIC_") {
+                c.arg("-e").arg(format!("{}={}", key, val));
+            }
+        }
+
+        // Mount host claude config/auth directory (read-write — Claude needs to write state)
+        if let Some(home) = std::env::var_os("HOME") {
+            let home_path = PathBuf::from(&home);
+            let claude_dir = home_path.join(".claude");
+            if claude_dir.exists() {
+                c.arg("-v").arg(format!(
+                    "{}:/home/node/.claude",
+                    claude_dir.display()
+                ));
+            }
+            // Mount .claude.json for onboarding/theme/user config
+            let claude_json = home_path.join(".claude.json");
+            if claude_json.exists() {
+                c.arg("-v").arg(format!(
+                    "{}:/home/node/.claude.json",
+                    claude_json.display()
+                ));
+            }
+        }
+
+        c.arg(image.as_str());
+        c.arg(&config.claude_bin);
+        c.args(claude_args);
+        c
+    } else {
+        log(&format!("Launching Claude (iteration {})...", iteration));
+        let mut c = Command::new(&config.claude_bin);
+        c.args(claude_args);
+        c
+    };
+
+    let mut child = match cmd
         .stdout(Stdio::piped())
         .stderr(Stdio::inherit())
         .spawn()
     {
         Ok(c) => c,
         Err(e) => {
-            log_error(&format!(
+            let bin = if config.image.is_some() { "docker" } else { &config.claude_bin };
-                "failed to spawn '{}': {}",
+            log_error(&format!("failed to spawn '{}': {}", bin, e));
-                config.claude_bin, e
-            ));
             return false;
         }
     };
 
+    // Register child PID so signal handler can kill it to unblock pipe reads
+    signal::set_child_pid(child.id() as i32);
+
     // Compute log path
     let log_path = config.log_dir.as_ref().map(|dir| {
         std::path::PathBuf::from(dir).join(format!("iteration-{}.jsonl", iteration))
@@ -258,6 +510,7 @@ fn invoke_claude(runner: &mut LoopRunner, config: &Config, iteration: u32) -> bo
     };
 
     // Child has exited; clear it from runner
+    signal::set_child_pid(0);
     runner.child = None;
 
     log(&format!(
@@ -267,6 +520,170 @@ fn invoke_claude(runner: &mut LoopRunner, config: &Config, iteration: u32) -> bo
     status
 }
 
+/// Invoke the judge — a fresh Claude with zero implementation context.
+/// Returns true if the judge's verdict is PASS.
+fn invoke_judge(runner: &mut LoopRunner, config: &Config, iteration: u32) -> bool {
+    let judge_bin = match &config.judge {
+        Some(bin) => bin.clone(),
+        None => {
+            log_error("no 'judge' directive in config — cannot invoke judge");
+            return false;
+        }
+    };
+
+    let judge_prompt = "\
+Read .loop/judge.md. It describes what to verify.
+Test the feature exactly as described. You have full shell access.
+When done, write your verdict to .loop/verdict.md in this exact format:
+
+VERDICT: PASS
+
+<what you tested and what happened>
+
+or
+
+VERDICT: FAIL
+
+<what you tested, what went wrong, and what the correct behavior should be>";
+
+    let claude_args = [
+        "--dangerously-skip-permissions",
+        "--output-format",
+        "stream-json",
+        "-p",
+        judge_prompt,
+    ];
+
+    let mut cmd = if let Some(ref image) = config.image {
+        log(&format!(
+            "Launching judge in container (iteration {})...",
+            iteration
+        ));
+
+        let workdir = std::env::current_dir()
+            .unwrap_or_else(|_| PathBuf::from("."))
+            .to_string_lossy()
+            .to_string();
+
+        let mut c = Command::new("docker");
+        c.args([
+            "run",
+            "--rm",
+            "-i",
+            "--network=host",
+            "--cap-add=NET_ADMIN",
+            "--cap-add=NET_RAW",
+        ]);
+        c.arg("-v").arg(format!("{}:/workspace", workdir));
+        c.arg("-w").arg("/workspace");
+
+        for (key, val) in std::env::vars() {
+            if key.starts_with("CLAUDE_") || key.starts_with("ANTHROPIC_") {
+                c.arg("-e").arg(format!("{}={}", key, val));
+            }
+        }
+
+        if let Some(home) = std::env::var_os("HOME") {
+            let home_path = PathBuf::from(&home);
+            let claude_dir = home_path.join(".claude");
+            if claude_dir.exists() {
+                c.arg("-v").arg(format!(
+                    "{}:/home/node/.claude",
+                    claude_dir.display()
+                ));
+            }
+            let claude_json = home_path.join(".claude.json");
+            if claude_json.exists() {
+                c.arg("-v").arg(format!(
+                    "{}:/home/node/.claude.json",
+                    claude_json.display()
+                ));
+            }
+        }
+
+        c.arg(image.as_str());
+        c.arg(&judge_bin);
+        c.args(claude_args);
+        c
+    } else {
+        log(&format!("Launching judge (iteration {})...", iteration));
+        let mut c = Command::new(&judge_bin);
+        c.args(claude_args);
+        c
+    };
+
+    let mut child = match cmd
+        .stdout(Stdio::piped())
+        .stderr(Stdio::inherit())
+        .spawn()
+    {
+        Ok(c) => c,
+        Err(e) => {
+            let bin = if config.image.is_some() { "docker" } else { &judge_bin };
+            log_error(&format!("failed to spawn judge '{}': {}", bin, e));
+            return false;
+        }
+    };
+
+    signal::set_child_pid(child.id() as i32);
+
+    let log_path = config.log_dir.as_ref().map(|dir| {
+        std::path::PathBuf::from(dir).join(format!("judge-{}.jsonl", iteration))
+    });
+
+    if let Some(stdout) = child.stdout.take() {
+        runner.child = Some(child);
+        stream::filter_stream(stdout, log_path.as_deref());
+        if signal::interrupted() {
+            return false;
+        }
+    } else {
+        runner.child = Some(child);
+    }
+
+    let status = if let Some(ref mut child) = runner.child {
+        match child.wait() {
+            Ok(s) => {
+                if signal::interrupted() {
+                    return false;
+                }
+                s.success()
+            }
+            Err(e) => {
+                log_error(&format!("failed to wait on judge process: {}", e));
+                false
+            }
+        }
+    } else {
+        false
+    };
+
+    signal::set_child_pid(0);
+    runner.child = None;
+
+    if !status {
+        log_error("Judge process exited with failure");
+        return false;
+    }
+
+    // Read verdict
+    match fs::read_to_string(VERDICT_PATH) {
+        Ok(content) => {
+            let pass = content.starts_with("VERDICT: PASS");
+            if pass {
+                log(&format!("{}{}Judge verdict: PASS{}", GREEN, BOLD, RESET));
+            } else {
+                log(&format!("{}Judge verdict: FAIL{}", YELLOW, RESET));
+            }
+            pass
+        }
+        Err(e) => {
+            log_error(&format!("failed to read {}: {}", VERDICT_PATH, e));
+            false
+        }
+    }
+}
+
 /// Run boundary check and all configured guards.
 /// Returns true if everything passed.
 fn run_all_guards(config: &Config) -> bool {
@@ -331,6 +748,56 @@ fn run_all_guards(config: &Config) -> bool {
     all_passed
 }
 
+fn init(runner: &str) -> i32 {
+    let loop_dir = Path::new(".loop");
+    if !loop_dir.exists() {
+        if let Err(e) = fs::create_dir(loop_dir) {
+            log_error(&format!("failed to create .loop/: {}", e));
+            return 1;
+        }
+        log("Created .loop/");
+    }
+
+    let files: Vec<(&str, &str)> = match runner {
+        "loop" => vec![
+            (CONF_PATH, DEFAULT_GUARD_CONF),
+            (PROTOCOL_PATH, DEFAULT_PROTOCOL),
+            (PLAN_PATH, ""),
+            (NOTES_PATH, ""),
+            (GUARD_RESULTS_PATH, ""),
+        ],
+        "brute" => vec![
+            (CONF_PATH, DEFAULT_BRUTE_CONF),
+            (PROTOCOL_PATH, DEFAULT_BRUTE_PROTOCOL),
+            (TASK_PATH, ""),
+            (JUDGE_PATH, ""),
+            (NOTES_PATH, ""),
+            (VERDICT_PATH, ""),
+        ],
+        other => {
+            log_error(&format!("unknown runner type '{}'", other));
+            return 2;
+        }
+    };
+
+    log(&format!("Initializing '{}' runner...", runner));
+
+    for (path, content) in &files {
+        let p = Path::new(path);
+        if p.exists() {
+            log(&format!("skip (exists): {}", path));
+        } else {
+            if let Err(e) = fs::write(p, content) {
+                log_error(&format!("failed to write {}: {}", path, e));
+                return 1;
+            }
+            log(&format!("created: {}", path));
+        }
+    }
+
+    0
+}
+
 fn run_loop(dry_run: bool) -> i32 {
     // Load config
     let config = match Config::load(Path::new(CONF_PATH)) {
@@ -342,11 +809,15 @@ fn run_loop(dry_run: bool) -> i32 {
     };
 
     log(&format!(
-        "Config loaded: claude={}, max_tail={}, {} scope rules, {} guards",
+        "Config loaded: claude={}, max_tail={}, {} scope rules, {} guards{}",
         config.claude_bin,
         config.max_tail,
         config.scope_rules.len(),
-        config.guards.len()
+        config.guards.len(),
+        config.image.as_ref().map_or(
+            String::from(", sandbox=off"),
+            |img| format!(", image={}", img)
+        )
     ));
 
     // Preflight
@@ -388,8 +859,9 @@ fn run_loop(dry_run: bool) -> i32 {
 
         if dry_run {
             log("(dry-run) Skipping Claude invocation");
-        } else {
+        } else if !invoke_claude(&mut runner, &config, iteration) {
-            invoke_claude(&mut runner, &config, iteration);
+            log_error("Claude invocation failed — aborting loop");
+            return 1;
         }
 
         if signal::interrupted() {
@@ -436,6 +908,173 @@ fn run_loop(dry_run: bool) -> i32 {
     }
 }
 
+/// Protected files for the brute runner.
+const BRUTE_PROTECTED_FILES: &[&str] = &[PROTOCOL_PATH, TASK_PATH, JUDGE_PATH, CONF_PATH];
+
+fn run_brute(dry_run: bool) -> i32 {
+    // Load config
+    let config = match Config::load(Path::new(CONF_PATH)) {
+        Ok(c) => c,
+        Err(e) => {
+            log_error(&e);
+            process::exit(1);
+        }
+    };
+
+    log(&format!(
+        "Config loaded: runner=brute, claude={}, judge={}, max_tail={}, {} scope rules, {} guards{}",
+        config.claude_bin,
+        config.judge.as_deref().unwrap_or("(none)"),
+        config.max_tail,
+        config.scope_rules.len(),
+        config.guards.len(),
+        config.image.as_ref().map_or(
+            String::from(", sandbox=off"),
+            |img| format!(", image={}", img)
+        )
+    ));
+
+    // Preflight: require protocol.md, task.md, judge.md, ci.conf
+    for path in &[PROTOCOL_PATH, TASK_PATH, JUDGE_PATH, CONF_PATH] {
+        if !Path::new(path).exists() {
+            log_error(&format!("required file not found: {}", path));
+            process::exit(1);
+        }
+    }
+
+    // Create notes.md and verdict.md if missing
+    for path in &[NOTES_PATH, VERDICT_PATH] {
+        if !Path::new(path).exists() {
+            if let Err(e) = fs::write(path, "") {
+                log_error(&format!("cannot create {}: {}", path, e));
+                process::exit(1);
+            }
+        }
+    }
+
+    // Clear verdict
+    let _ = fs::write(VERDICT_PATH, "");
+
+    log("Preflight OK");
+
+    // Backup protected files
+    let backup_dir = std::env::temp_dir().join(format!("yoke-backup-{}", process::id()));
+    if let Err(e) = fs::create_dir_all(&backup_dir) {
+        log_error(&format!("failed to create backup dir: {}", e));
+        process::exit(1);
+    }
+    for path in BRUTE_PROTECTED_FILES {
+        let src = Path::new(path);
+        if src.exists() {
+            let dest = backup_dir.join(src.file_name().unwrap());
+            if let Err(e) = fs::copy(src, &dest) {
+                log_error(&format!("failed to backup {}: {}", path, e));
+                process::exit(1);
+            }
+        }
+    }
+    log(&format!("Backups in {}", backup_dir.display()));
+
+    let mut runner = LoopRunner::new(backup_dir);
+    let mut iteration: u32 = 0;
+
+    loop {
+        if signal::interrupted() {
+            log("Interrupted \u{2014} shutting down");
+            return 130;
+        }
+        iteration += 1;
+        eprintln!();
+        eprintln!(
+            "{}{}╔══════════════════════════════════════╗{}",
+            BOLD, CYAN, RESET
+        );
+        eprintln!(
+            "{}{}║     Brute Iteration {:>4}             ║{}",
+            BOLD, CYAN, iteration, RESET
+        );
+        eprintln!(
+            "{}{}╚══════════════════════════════════════╝{}",
+            BOLD, CYAN, RESET
+        );
+
+        // Restore protected files
+        for path in BRUTE_PROTECTED_FILES {
+            let src_name = Path::new(path).file_name().unwrap();
+            let backup_file = runner.backup_dir.join(src_name);
+            if backup_file.exists() {
+                if let Err(e) = fs::copy(&backup_file, path) {
+                    eprintln!(
+                        "{}{}[yoke] WARNING:{} failed to restore {}: {}",
+                        BOLD, YELLOW, RESET, path, e
+                    );
+                }
+            }
+        }
+
+        // Clear verdict
+        let _ = fs::write(VERDICT_PATH, "");
+
+        if dry_run {
+            log("(dry-run) Skipping Claude invocation");
+        } else if !invoke_claude(&mut runner, &config, iteration) {
+            log_error("Claude invocation failed — aborting loop");
+            return 1;
+        }
+
+        if signal::interrupted() {
+            log("Interrupted \u{2014} shutting down");
+            return 130;
+        }
+
+        // Run guards
+        let guards_passed = run_all_guards(&config);
+
+        if !guards_passed {
+            log(&format!(
+                "{}Guards failed \u{2014} worker will see results next iteration{}",
+                YELLOW, RESET
+            ));
+            if dry_run {
+                log("(dry-run) Exiting after one iteration");
+                return 1;
+            }
+            continue;
+        }
+
+        log(&format!("{}{}All guards passed{}", GREEN, BOLD, RESET));
+
+        if dry_run {
+            log("(dry-run) Guards passed \u{2014} exiting after one iteration");
+            return 0;
+        }
+
+        // Guards passed — invoke judge
+        log("Guards passed \u{2014} invoking judge...");
+        let pass = invoke_judge(&mut runner, &config, iteration);
+
+        if signal::interrupted() {
+            log("Interrupted \u{2014} shutting down");
+            return 130;
+        }
+
+        if pass {
+            eprintln!();
+            eprintln!(
+                "{}{}  Judge says PASS \u{2014} brute loop complete  {}",
+                GREEN, BOLD, RESET
+            );
+            eprintln!();
+            return 0;
+        }
+
+        log(&format!(
+            "{}Judge says FAIL \u{2014} worker will see verdict next iteration{}",
+            YELLOW, RESET
+        ));
+    }
+}
+
 fn main() {
     signal::install();
     let args: Vec<String> = std::env::args().collect();
@@ -446,6 +1085,33 @@ fn main() {
     }
 
     match args[1].as_str() {
+        "init" => {
+            if args.get(2).is_some_and(|a| a == "--help" || a == "-h") {
+                print_init_help();
+                return;
+            }
+            let mut runner = "loop";
+            let mut i = 2;
+            while i < args.len() {
+                match args[i].as_str() {
+                    "--runner" => {
+                        i += 1;
+                        if i >= args.len() {
+                            log_error("--runner requires a value (loop or brute)");
+                            process::exit(2);
+                        }
+                        runner = &args[i];
+                    }
+                    other => {
+                        log_error(&format!("unknown flag '{}'", other));
+                        print_init_help();
+                        process::exit(2);
+                    }
+                }
+                i += 1;
+            }
+            process::exit(init(runner));
+        }
         "run" => {
             // Check for --help before other flags
             if args.get(2).is_some_and(|a| a == "--help" || a == "-h") {
@@ -458,7 +1124,22 @@ fn main() {
                 print_run_help();
                 process::exit(2);
             }
-            process::exit(run_loop(dry_run));
+            // Load config to determine runner type
+            let config = match Config::load(Path::new(CONF_PATH)) {
+                Ok(c) => c,
+                Err(e) => {
+                    log_error(&e);
+                    process::exit(1);
+                }
+            };
+            match config.runner.as_str() {
+                "loop" => process::exit(run_loop(dry_run)),
+                "brute" => process::exit(run_brute(dry_run)),
+                other => {
+                    log_error(&format!("unknown runner type '{}' in config", other));
+                    process::exit(2);
+                }
+            }
         }
         "--help" | "-h" | "help" => {
             print_usage();

src/signal.rs

@@ -1,17 +1,30 @@
-use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicI32, Ordering};
 
 static INTERRUPTED: AtomicBool = AtomicBool::new(false);
+static CHILD_PID: AtomicI32 = AtomicI32::new(0);
 
 extern "C" fn sigint_handler(_sig: i32) {
     INTERRUPTED.store(true, Ordering::Relaxed);
+    // Kill the child to close the pipe and unblock reader.lines().
+    // Rust's BufReader retries on EINTR internally, so the only way
+    // to break out of the blocking read is to close the write end.
+    let pid = CHILD_PID.load(Ordering::Relaxed);
+    if pid > 0 {
+        kill(pid, 9); // SIGKILL — child already got SIGINT from the terminal
+    }
 }
 
 unsafe extern "C" {
     safe fn signal(sig: i32, handler: extern "C" fn(i32)) -> usize;
+    safe fn kill(pid: i32, sig: i32) -> i32;
 }
 
 pub fn install() {
-    signal(2, sigint_handler); // SIGINT = 2
+    signal(2, sigint_handler);
+}
+
+pub fn set_child_pid(pid: i32) {
+    CHILD_PID.store(pid, Ordering::Relaxed);
 }
 
 pub fn interrupted() -> bool {

src/stream.rs

@@ -135,17 +135,44 @@ pub fn filter_stream(stdout: ChildStdout, log_path: Option<&Path>) {
                 } else if let Some(text) = extract_str(&line, "text") {
                     let trimmed = text.trim();
                     if !trimmed.is_empty() {
-                        for text_line in trimmed.lines().take(3) {
+                        for text_line in trimmed.lines() {
-                            let truncated = if text_line.len() > 120 {
+                            println!("{}  {}{}", DIM, text_line, RESET);
-                                &text_line[..120]
-                            } else {
-                                text_line
-                            };
-                            println!("{}  {}{}", DIM, truncated, RESET);
                         }
                     }
                 }
             }
+            // stream_event → streaming deltas
+            Some("stream_event") => {
+                if line.contains("\"content_block_delta\"") {
+                    if line.contains("\"text_delta\"") {
+                        if let Some(text) = extract_str(&line, "text") {
+                            print!("{}{}{}", DIM, text, RESET);
+                            std::io::stdout().flush().ok();
+                        }
+                    }
+                    // input_json_delta → skip silently
+                } else if line.contains("\"content_block_start\"") {
+                    if !line.contains("\"tool_use\"") {
+                        println!();
+                    }
+                } else if line.contains("\"content_block_stop\"") {
+                    println!();
+                }
+                // message_start, message_delta, message_stop → skip
+            }
+            // user → tool result summaries
+            Some("user") => {
+                if line.contains("\"tool_result\"") {
+                    // Estimate content length from the line
+                    let content_len = if let Some(start) = line.find("\"content\":\"") {
+                        let after = &line[start + 11..];
+                        after.find('"').unwrap_or(after.len())
+                    } else {
+                        0
+                    };
+                    println!("{}  \u{2190} result ({}b){}", DIM, content_len, RESET);
+                }
+            }
             // result → green bold summary
             Some("result") => {
                 let cost = extract_num(&line, "cost_usd").unwrap_or(0.0);