Add web server, event stream, and Rive contract

- crows serve: HTTP API, Server-Sent Events per list, web approvals
  with a 10-minute fail-safe timeout; localhost only by default
- Shared pipeline for command line and server; trust.changed events
- EVENTS.md: server/UI contract; RIVE_CONTRACT.md: data-binding spec
  for the animator (one Crow artboard for v1)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UQnSw4RRWp8uqpj3nsnnXF

.gitignore

@@ -3,3 +3,4 @@
 *.crows.md
 node_modules/
 dist/
+/somanycrows

EVENTS.md

@@ -0,0 +1,40 @@
+# Events: the shared contract
+
+The Go server emits these over Server-Sent Events (SSE). The web UI turns them into Rive state machine inputs. Both sides build against this file; change it first, then the code.
+
+Each SSE message: `event: <name>` and `data: <JSON>`. Every payload includes `list_id` and `ts` (RFC 3339).
+
+| Event | Payload (besides list_id, ts) | Meaning |
+|---|---|---|
+| `list.started` | `items: [{item_id, text}]`, `requester` | Flock accepted a list |
+| `item.triaged` | `item_id`, `mode` (solo/split/murder), `task_type`, `subtasks[]`, `reason`, `needs_approval` (bool) | Sentry made its call |
+| `crow.flying` | `item_id`, `crow` | A crow (or Sentry, Elder) took off |
+| `crow.landed` | `item_id`, `crow`, `ok` (bool), `tokens`, `error?` | A crow came back, or didn't |
+| `item.answered` | `item_id`, `answer`, `crows[]`, `needs_approval` (bool) | Result ready |
+| `verdict` | `item_id`, `target` (triage/output), `verdict` (approved/rejected/auto/timeout) | Judgment recorded |
+| `trust.changed` | `holder` (crow name or "flock"), `task_type`, `from`, `to` (0 stranger, 1 regular, 2 trusted) | Level up or down |
+| `item.skipped` | `item_id`, `reason` | Item dropped (rejected triage, budget, failure) |
+| `requester.pranked` | `message`, `cooldown_s` | Abuse response |
+| `list.finished` | `tokens_used`, `token_budget` | Done |
+
+## HTTP API
+
+| Method | Path | Body / query | Returns |
+|---|---|---|---|
+| POST | `/api/lists` | `{"text": "<todo list>", "requester": "<id>"}` | `{"list_id"}`, or 429 with `{"message","cooldown_s"}` when pranked |
+| GET | `/api/events` | `?list_id=` | SSE stream |
+| POST | `/api/verdicts` | `{"item_id", "target": "triage"\|"output", "approve": bool}` | 204 |
+| GET | `/api/trust` | | ledger JSON |
+
+Pending approvals that get no answer within 10 minutes count as rejected (`verdict: timeout`). Fail safe.
+
+## Settled details
+
+- `item_id` is `<list_id>-<n>`, numbered from 1 in list order.
+- `POST /api/lists` returns 202. Bad input returns 400 with `{"message"}`.
+- `POST /api/verdicts` returns 404 when nothing is waiting (including a second answer), 400 for a bad body. `approve` is required, so a missing value is never read as a no.
+- When trust skips approval, the server still emits `verdict: "auto"`, so every target gets exactly one verdict.
+- `crow.flying` and `crow.landed` fire for the Sentry and Elder too.
+- `requester.pranked` goes to every list of that requester's still flying; if none, only the 429 is sent.
+- Each SSE message carries an `id:` line, so clients can reconnect with `Last-Event-ID`. Heartbeat comment every 15 seconds.
+- The server listens on localhost only by default. There is no login yet, and requester names are self-asserted.

README.md

@@ -16,6 +16,26 @@ ANTHROPIC_API_KEY=... ./crows run todo.txt   # real crows (Claude)
 
 Optional: `CROWS_MODEL` overrides the model. Results land in `todo.crows.md`; state lives in `.crows/`.
 
+## Web server
+
+```
+./crows serve                   # localhost:8080; API + Server-Sent Events (SSE); Ctrl-C to stop
+```
+
+The server runs the same pipeline as `crows run`, but items fly in parallel and approvals come over HTTP. `EVENTS.md` is the contract for events and the API:
+
+```
+curl -XPOST localhost:8080/api/lists -d '{"text":"- [ ] What is a crow","requester":"me"}'
+curl -N "localhost:8080/api/events?list_id=<id>"        # replays the list's events so far, then streams
+curl -XPOST localhost:8080/api/verdicts -d '{"item_id":"<id>-1","target":"triage","approve":true}'
+curl localhost:8080/api/trust
+```
+
+- Item IDs are `<list_id>-<n>`, numbered from 1 in list order.
+- Approvals left unanswered for 10 minutes count as rejected (`verdict: timeout`). `-approval-timeout` changes this for testing.
+- A flooding requester gets 429 with `message` and `cooldown_s`; any list of theirs that is still flying also gets `requester.pranked`.
+- POST bodies are capped at 64 KB. Static files are served from `./web` when that folder exists.
+
 ## How an item flies
 
 1. **Sentry** classifies it: `solo` (one crow), `split` (2–4 subtasks in parallel), or `murder` (3 crows answer independently).

RIVE_CONTRACT.md

@@ -0,0 +1,162 @@
+# Rive contract: the `crows.riv` file
+
+The animator builds `crows.riv` against this file, and the web code drives it from the events in `EVENTS.md`. Both sides build against this file, so change it first and then the code. Each animation exists only because an `EVENTS.md` event fires it.
+
+Style: Duolingo-like. Chunky, expressive crows with big squash-and-stretch reactions and readable silhouettes at 96 pixels. The approve and reject buttons stay in HTML for v1 (see "Why buttons stay in HTML").
+
+## Rive approach: data binding, not inputs
+
+Rive now marks state machine inputs as deprecated and recommends data binding for new work ([migration guide](https://rive.app/docs/editor/data-binding/migration-guide), [inputs](https://rive.app/docs/runtimes/inputs)). So this file uses **view models** in place of inputs:
+
+- A **view model** defines the data shape. A **view model instance** holds the values, one per crow on screen ([view models](https://rive.app/docs/editor/data-binding/view-models.md)).
+- Number, Boolean, Trigger, Enum, String and Color properties can drive state machine transition conditions or bind straight to scene elements ([property types](https://rive.app/docs/editor/data-binding/property-types.md), [transitions](https://rive.app/docs/editor/state-machine/transitions)).
+- An enum can drive a Solo when its values match the Solo children's **names and order**, and those names must be exported ([enums](https://rive.app/docs/editor/data-binding/enums.md)).
+- Layers play at the same time, one state per layer, and the lower layer wins when two layers animate the same property ([layers](https://rive.app/docs/editor/state-machine/layers.md)). Any State reaches a state from wherever the layer is. Exit State stops a layer ([states](https://rive.app/docs/editor/state-machine/states.md)).
+
+## 1. Artboards
+
+| Artboard | v1? | Purpose |
+|---|---|---|
+| `Crow` | yes | One reusable character. It covers all 8 crows plus the Sentry and Elder, using a `role` enum that switches the costume. |
+| `Perch` | later | A scene with a branch of crows rendered as an Artboard List of `Crow` items ([lists](https://rive.app/docs/editor/data-binding/lists.md)), plus flock-wide celebrations. |
+| `Splat` | later | A full-screen "gift on your windshield" overlay for the prank. |
+
+In v1, the web page puts one `Crow` canvas per visible crow and lays them out with HTML and CSS. The Sentry and Elder are **variants** of `Crow`, not separate artboards, so the whole cast shares one rig.
+
+Artboard spec: 256 × 256, transparent background, crow centered with its feet on a baseline 40 pixels from the bottom, so the crows line up in a row.
+
+## 2. `Crow` artboard
+
+State machine: `CrowMachine`. View model: `CrowModel`, set as the artboard's default view model.
+
+### `CrowModel` properties
+
+| Property | Type | Values / range | Drives |
+|---|---|---|---|
+| `role` | Enum `Role` | `crow`, `sentry`, `elder` | Solo `Costume` (children named `crow`, `sentry`, `elder`, in that order). The Sentry wears a lookout cap and the Elder wears spectacles and a gray ruff. |
+| `name` | String | e.g. `Hugin`, `Sentry` | Text run `nameplate` under the feet |
+| `pose` | Enum `Pose` | `perched`, `flying`, `waiting`, `grounded` | `Body` layer |
+| `trust` | Number | integer 0–2 (0 stranger, 1 regular, 2 trusted) | `Badge` layer |
+| `cheer` | Trigger | | `Reaction` layer: happy hop with a wing pump |
+| `sulk` | Trigger | | `Reaction` layer: droop, single feather falls. Sad, never angry. |
+| `levelUp` | Trigger | | `Reaction` layer: the level-up celebration (spin, confetti, badge shine). It's the biggest moment in the file. |
+| `levelDown` | Trigger | | `Reaction` layer: badge dims, sheepish shrug |
+| `prank` | Trigger | | `Reaction` layer: mischievous grin, flies off frame, a "plop" sound cue, returns smug |
+
+The 8 crows tell themselves apart by `name` in v1. A `plumage` Color property for per-crow tints is later polish.
+
+### Layers, states and transitions
+
+**Layer `Body`**, a loop that's always running:
+
+| State | Loop | Notes |
+|---|---|---|
+| `perched` | yes | Entry state. Idle breathing, blinking, a head tilt every few seconds. |
+| `flying` | yes | Wings flapping, a slight bob. It reads as "working". |
+| `waiting` | yes | Holds a rolled scroll up toward the viewer and taps a foot. It reads as "your turn". |
+| `grounded` | yes | Sitting dazed with stars circling. It means failure or timeout. |
+
+Transitions: Any State → each state when `pose` equals that value, with a duration of 200 milliseconds (ms). There's no Exit Time, so a pose change is instant to read.
+
+**Layer `Reaction`**, one-shots on top of `Body`:
+
+- Entry → `none`, an empty state.
+- Any State → `cheer`, `sulk`, `levelUp`, `levelDown` or `prank` on the trigger of the same name.
+- Each one-shot → `none` with Exit Time at 100%.
+- Lengths: `cheer` and `sulk` at most 0.8 seconds, `levelUp` at most 2 seconds, `levelDown` at most 1 second, `prank` at most 2.5 seconds.
+- Animate only what `Body` doesn't need to own (face, wings, effects), or put `Reaction` below `Body` in the layer list so the reaction wins while it plays.
+
+**Layer `Badge`**:
+
+- Any State → `badge0`, `badge1` or `badge2` when `trust` equals 0, 1 or 2, with a duration of 150 ms.
+- `badge0` shows no badge, `badge1` a bronze chest feather, `badge2` a gold chest feather with a gentle shimmer loop.
+
+## 3. Event → animation mapping
+
+The web code keeps a map from `item_id` to `crows[]` (from `item.answered`) so that it can aim `verdict` at the right crows. The `crow` field values `Sentry` and `Elder` select the instances with `role` set to `sentry` and `elder`.
+
+| `EVENTS.md` event | Condition | Instance(s) | Set |
+|---|---|---|---|
+| `list.started` | | Sentry | Create and show the Sentry. `pose = perched`. |
+| `item.triaged` | `needs_approval` true | Sentry | `pose = waiting` |
+| `item.triaged` | `needs_approval` false | | No animation. The HTML shows the mode and reason. |
+| `crow.flying` | | `crow` (create on first sight) | `pose = flying` |
+| `crow.landed` | `ok` true | `crow` | `pose = perched` |
+| `crow.landed` | `ok` false | `crow` | `pose = grounded` |
+| `item.answered` | `needs_approval` true | each of `crows[]` | `pose = waiting` |
+| `item.answered` | `needs_approval` false | | No animation. A `verdict: auto` follows. |
+| `verdict` | `target` triage, `approved` | Sentry | `cheer`, then `pose = perched` |
+| `verdict` | `target` triage, `rejected` or `timeout` | Sentry | `sulk`, then `pose = perched` |
+| `verdict` | `target` triage, `auto` | | No animation. A trusted Sentry just keeps going. |
+| `verdict` | `target` output, `approved` or `auto` | each of the item's `crows[]` | `cheer`, then `pose = perched` |
+| `verdict` | `target` output, `rejected` or `timeout` | each of the item's `crows[]` | `sulk`, then `pose = perched` |
+| `trust.changed` | `holder` is a crow, `to` > `from` | `holder` | `trust = to`, then `levelUp` |
+| `trust.changed` | `holder` is a crow, `to` < `from` | `holder` | `trust = to`, then `levelDown` |
+| `trust.changed` | `holder` is `flock` | | No animation in v1 (HTML banner). Later: a `Perch` celebration. |
+| `item.skipped` | | | No animation. The HTML strikes the item through, and any instance still `flying` for that item goes to `pose = perched`. |
+| `requester.pranked` | | one random crow on screen, or the Sentry if it's alone | `prank`. Later: the `Splat` overlay. The HTML shows `message` and a `cooldown_s` countdown. |
+| `list.finished` | | every crow on screen | `pose = perched`, then `cheer` |
+
+Two web-side notes:
+
+- **Pranks.** `POST /api/lists` answers a pranked requester with a 429 error and no `list_id`, so there may be no event stream to deliver `requester.pranked`. The web code treats that 429 response the same as the event and fires `prank` on the Sentry.
+- **Badges.** `trust` is per crow *and* per task type, so a badge shows the level for the task type of the item the crow is working on now. The web code seeds `trust` from `GET /api/trust` when it creates an instance, and updates it on `trust.changed` only when `task_type` matches.
+
+## 4. Naming conventions
+
+The web code matches these strings exactly, so they're case-sensitive.
+
+| Thing | Case | Names |
+|---|---|---|
+| File | lowercase | `crows.riv` |
+| Artboards | PascalCase | `Crow`, `Perch`, `Splat` |
+| State machines | PascalCase + `Machine` | `CrowMachine`, `PerchMachine` |
+| View models | PascalCase + `Model` | `CrowModel` |
+| Enum types | PascalCase | `Role`, `Pose` |
+| Enum values | lowercase, one word, matching server strings where they exist | `crow`, `sentry`, `elder`, `perched`, `flying`, `waiting`, `grounded` |
+| Properties (including triggers) | camelCase | `role`, `name`, `pose`, `trust`, `cheer`, `sulk`, `levelUp`, `levelDown`, `prank` |
+| States and layers | camelCase states, PascalCase layers | `perched`, `badge2`, `Body`, `Reaction`, `Badge` |
+| Exported objects | as listed | Solo `Costume` (children `crow`, `sentry`, `elder`), text run `nameplate` |
+
+The web code binds one blank instance per crow, using API names from the [web data binding docs](https://rive.app/docs/runtimes/web/data-binding):
+
+```js
+const r = new rive.Rive({ src: "crows.riv", canvas, artboard: "Crow",
+  stateMachines: "CrowMachine", autoplay: true, onLoad: () => {
+    const vmi = r.viewModelByName("CrowModel").instance();
+    r.bindViewModelInstance(vmi);
+    vmi.enum("role").value = "crow";
+    vmi.string("name").value = "Hugin";
+    vmi.number("trust").value = 1;
+    vmi.enum("pose").value = "flying";   // crow.flying
+    vmi.trigger("cheer").trigger();      // verdict approved
+  } });
+```
+
+Keep `autoBind` off. Every crow needs its own instance, or setting one crow's `pose` would move them all.
+
+## 5. v1 minimum vs. later polish
+
+**v1 minimum**, the smallest set that makes the web UI work:
+
+1. The `Crow` artboard, the `CrowMachine` state machine and the `CrowModel` view model, named exactly as in section 4.
+2. The `role` Solo with all three costumes. The Sentry and Elder must read as different from the crows at a glance.
+3. The `name` text run.
+4. The `Body` layer with all four `pose` states.
+5. The `Reaction` layer with `cheer`, `sulk` and `levelUp`.
+6. The `Badge` layer with all three `trust` states.
+
+If `levelDown` or `prank` doesn't exist yet, the web code falls back to `sulk` and `cheer`, so they can ship a beat later without breaking anything.
+
+**Later polish**, in rough order:
+
+1. `levelDown` and `prank` reactions.
+2. A `plumage` Color property so each of the 8 crows has a distinct tint.
+3. The `Splat` artboard for the windshield gift.
+4. The `Perch` scene: an Artboard List of crows, murder huddles and split formations, and a flock `levelUp` on `trust.changed` with `holder` set to `flock`.
+5. A streak ring, a Duolingo-style progress bar toward promotion at 10 clean approvals. `EVENTS.md` carries no streak count today, so this needs a `streak` field added to `verdict` or `trust.changed` first.
+6. A Rive-drawn approve or reject button, if HTML buttons ever feel flat.
+
+## Why buttons stay in HTML
+
+Approval is the safety gate, and the server treats anything other than an explicit yes as a no. Real `<button>` elements give keyboard, screen reader and focus support for free, and an animation glitch can never swallow a click. Rive decorates the moment by having the crow hold up its scroll. The click itself belongs to the browser.

approve.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+)
+
+// StdinApprover asks at the terminal. It fails safe: anything but y/yes,
+// including no input at all, is a no.
+type StdinApprover struct {
+	mu sync.Mutex
+	in *bufio.Reader
+}
+
+func (s *StdinApprover) Approve(ctx context.Context, a Approval) string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	prompt := "  Accept this answer?"
+	if a.Target == "triage" {
+		prompt = "  Approve triage?"
+	}
+	if confirm(s.in, prompt) {
+		return "approved"
+	}
+	return "rejected"
+}
+
+// confirm fails safe: anything but y/yes, including no input at all, is a no.
+func confirm(in *bufio.Reader, prompt string) bool {
+	fmt.Print(prompt + " [y/N] ")
+	line, _ := in.ReadString('\n')
+	a := strings.ToLower(strings.TrimSpace(line))
+	if line == "" {
+		fmt.Println()
+	}
+	return a == "y" || a == "yes"
+}
+
+// WebApprover blocks an item's goroutine until POST /api/verdicts answers it,
+// or the timeout passes, which counts as a rejection.
+type WebApprover struct {
+	Timeout time.Duration
+
+	mu      sync.Mutex
+	pending map[string]chan bool // key: item_id|target
+}
+
+func NewWebApprover(timeout time.Duration) *WebApprover {
+	return &WebApprover{Timeout: timeout, pending: map[string]chan bool{}}
+}
+
+func approvalKey(itemID, target string) string { return itemID + "|" + target }
+
+func (w *WebApprover) Approve(ctx context.Context, a Approval) string {
+	key := approvalKey(a.ItemID, a.Target)
+	ch := make(chan bool, 1)
+	w.mu.Lock()
+	w.pending[key] = ch
+	w.mu.Unlock()
+	defer func() {
+		w.mu.Lock()
+		delete(w.pending, key)
+		w.mu.Unlock()
+	}()
+
+	timer := time.NewTimer(w.Timeout)
+	defer timer.Stop()
+	select {
+	case ok := <-ch:
+		if ok {
+			return "approved"
+		}
+		return "rejected"
+	case <-timer.C:
+		return "timeout"
+	case <-ctx.Done():
+		return "rejected"
+	}
+}
+
+// Resolve delivers a human's verdict. It reports false if nothing is waiting.
+func (w *WebApprover) Resolve(itemID, target string, approve bool) bool {
+	key := approvalKey(itemID, target)
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	ch, ok := w.pending[key]
+	if !ok {
+		return false
+	}
+	delete(w.pending, key) // one verdict per question
+	ch <- approve
+	return true
+}

flock.go

@@ -58,12 +58,24 @@ func (b *Budget) Check() error {
 	return nil
 }
 
+func (b *Budget) Spent() int {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.spent
+}
+
 func (b *Budget) Add(n int) {
 	b.mu.Lock()
 	b.spent += n
 	b.mu.Unlock()
 }
 
+// Watcher hears every takeoff and landing (Sentry and Elder included). It may be nil.
+type Watcher interface {
+	Flying(crow string)
+	Landed(crow string, tokens int, err error)
+}
+
 type Flock struct {
 	brain Brain
 	g     Guardrails
@@ -91,7 +103,7 @@ func (f *Flock) pick(n int) []string {
 }
 
 // ask is the only way any crow touches the model: budget, flock cap, timeout, log.
-func (f *Flock) ask(ctx context.Context, crow, system, prompt string, budgets ...*Budget) (string, error) {
+func (f *Flock) ask(ctx context.Context, w Watcher, crow, system, prompt string, budgets ...*Budget) (string, error) {
 	for _, b := range budgets {
 		if err := b.Check(); err != nil {
 			f.log.Write(Event{Kind: "grounded", Crow: crow, Error: err.Error()})
@@ -101,6 +113,9 @@ func (f *Flock) ask(ctx context.Context, crow, system, prompt string, budgets ..
 	f.sem <- struct{}{}
 	defer func() { <-f.sem }()
 
+	if w != nil {
+		w.Flying(crow)
+	}
 	cctx, cancel := context.WithTimeout(ctx, f.g.CrowTimeout)
 	defer cancel()
 	start := time.Now()
@@ -116,11 +131,14 @@ func (f *Flock) ask(ctx context.Context, crow, system, prompt string, budgets ..
 		e.Error = err.Error()
 	}
 	f.log.Write(e)
+	if w != nil {
+		w.Landed(crow, tokens, err)
+	}
 	return text, err
 }
 
-func (f *Flock) Triage(ctx context.Context, item string, budgets ...*Budget) (Triage, error) {
+func (f *Flock) Triage(ctx context.Context, w Watcher, item string, budgets ...*Budget) (Triage, error) {
-	text, err := f.ask(ctx, "Sentry", sentrySystem, "ITEM: "+item, budgets...)
+	text, err := f.ask(ctx, w, "Sentry", sentrySystem, "ITEM: "+item, budgets...)
 	if err != nil {
 		return Triage{}, err
 	}
@@ -151,16 +169,16 @@ func (f *Flock) Triage(ctx context.Context, item string, budgets ...*Budget) (Tr
 	return t, nil
 }
 
-func (f *Flock) Execute(ctx context.Context, item string, t Triage, budgets ...*Budget) (Outcome, error) {
+func (f *Flock) Execute(ctx context.Context, w Watcher, item string, t Triage, budgets ...*Budget) (Outcome, error) {
 	switch t.Mode {
 	case "split":
 		// Split depth is 1: subtasks go straight to crows, never back to the Sentry.
 		crows := f.pick(len(t.Subtasks))
-		reports, err := f.fanOut(ctx, crows, t.Subtasks, budgets...)
+		reports, err := f.fanOut(ctx, w, crows, t.Subtasks, budgets...)
 		if err != nil {
 			return Outcome{}, err
 		}
-		return f.reconcile(ctx, item, crows, t.Subtasks, reports, budgets...)
+		return f.reconcile(ctx, w, item, crows, t.Subtasks, reports, budgets...)
 	case "murder":
 		n := min(f.g.MurderSize, f.g.MaxCrowsInFlight)
 		crows := f.pick(n)
@@ -168,19 +186,19 @@ func (f *Flock) Execute(ctx context.Context, item string, t Triage, budgets ...*
 		for i := range tasks {
 			tasks[i] = item
 		}
-		reports, err := f.fanOut(ctx, crows, tasks, budgets...)
+		reports, err := f.fanOut(ctx, w, crows, tasks, budgets...)
 		if err != nil {
 			return Outcome{}, err
 		}
-		return f.reconcile(ctx, item, crows, tasks, reports, budgets...)
+		return f.reconcile(ctx, w, item, crows, tasks, reports, budgets...)
 	default:
 		c := f.pick(1)[0]
-		ans, err := f.ask(ctx, c, crowSystem, "TASK: "+item, budgets...)
+		ans, err := f.ask(ctx, w, c, crowSystem, "TASK: "+item, budgets...)
 		return Outcome{Answer: ans, Crows: []string{c}}, err
 	}
 }
 
-func (f *Flock) fanOut(ctx context.Context, crows, tasks []string, budgets ...*Budget) ([]string, error) {
+func (f *Flock) fanOut(ctx context.Context, w Watcher, crows, tasks []string, budgets ...*Budget) ([]string, error) {
 	reports := make([]string, len(tasks))
 	errs := make([]error, len(tasks))
 	var wg sync.WaitGroup
@@ -188,7 +206,7 @@ func (f *Flock) fanOut(ctx context.Context, crows, tasks []string, budgets ...*B
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			reports[i], errs[i] = f.ask(ctx, crows[i], crowSystem, "TASK: "+tasks[i], budgets...)
+			reports[i], errs[i] = f.ask(ctx, w, crows[i], crowSystem, "TASK: "+tasks[i], budgets...)
 		}()
 	}
 	wg.Wait()
@@ -206,12 +224,12 @@ func (f *Flock) fanOut(ctx context.Context, crows, tasks []string, budgets ...*B
 	return reports, nil
 }
 
-func (f *Flock) reconcile(ctx context.Context, item string, crows, tasks, reports []string, budgets ...*Budget) (Outcome, error) {
+func (f *Flock) reconcile(ctx context.Context, w Watcher, item string, crows, tasks, reports []string, budgets ...*Budget) (Outcome, error) {
 	var sb strings.Builder
 	fmt.Fprintf(&sb, "ORIGINAL TASK: %s\n\n", item)
 	for i := range reports {
 		fmt.Fprintf(&sb, "--- %s on %q:\n%s\n\n", crows[i], tasks[i], reports[i])
 	}
-	ans, err := f.ask(ctx, "Elder", elderSystem, sb.String(), budgets...)
+	ans, err := f.ask(ctx, w, "Elder", elderSystem, sb.String(), budgets...)
 	return Outcome{Answer: ans, Crows: append(append([]string{}, crows...), "Elder")}, err
 }

hub.go

@@ -0,0 +1,156 @@
+package main
+
+import (
+	"encoding/json"
+	"sync"
+	"time"
+)
+
+// sseMsg is one event, already encoded, numbered within its list.
+type sseMsg struct {
+	ID   int
+	Name string
+	Data []byte
+}
+
+// listStream holds everything one list has said so far, plus who is listening.
+type listStream struct {
+	requester string
+	created   time.Time
+	finished  bool
+	history   []sseMsg
+	subs      map[chan sseMsg]struct{}
+}
+
+// Hub fans events out to SSE subscribers per list_id and keeps each list's
+// history in memory so late subscribers can catch up.
+type Hub struct {
+	mu    sync.Mutex
+	lists map[string]*listStream
+}
+
+func NewHub() *Hub {
+	return &Hub{lists: map[string]*listStream{}}
+}
+
+// subBuffer is how far a subscriber may fall behind before it is cut off.
+// It reconnects with Last-Event-ID and catches up from history.
+const subBuffer = 256
+
+// keepLists caps how many lists the hub remembers; the oldest finished go first.
+const keepLists = 200
+
+func (h *Hub) Open(listID, requester string) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	h.prune()
+	h.lists[listID] = &listStream{requester: requester, created: time.Now(), subs: map[chan sseMsg]struct{}{}}
+}
+
+func (h *Hub) prune() {
+	for len(h.lists) >= keepLists {
+		var oldest string
+		for id, ls := range h.lists {
+			if ls.finished && (oldest == "" || ls.created.Before(h.lists[oldest].created)) {
+				oldest = id
+			}
+		}
+		if oldest == "" {
+			return // every list is still flying; keep them all
+		}
+		h.drop(oldest)
+	}
+}
+
+func (h *Hub) drop(id string) {
+	for ch := range h.lists[id].subs {
+		close(ch)
+	}
+	delete(h.lists, id)
+}
+
+// ActiveLists returns the requester's lists that are still flying.
+func (h *Hub) ActiveLists(requester string) []string {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	var ids []string
+	for id, ls := range h.lists {
+		if ls.requester == requester && !ls.finished {
+			ids = append(ids, id)
+		}
+	}
+	return ids
+}
+
+// Publish records an event for a list and sends it to current subscribers.
+func (h *Hub) Publish(listID, name string, fields map[string]any) {
+	payload := map[string]any{}
+	for k, v := range fields {
+		payload[k] = v
+	}
+	payload["list_id"] = listID
+	payload["ts"] = time.Now().UTC().Format(time.RFC3339)
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return
+	}
+
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	ls := h.lists[listID]
+	if ls == nil {
+		return
+	}
+	m := sseMsg{ID: len(ls.history) + 1, Name: name, Data: data}
+	ls.history = append(ls.history, m)
+	if name == "list.finished" {
+		ls.finished = true
+	}
+	for ch := range ls.subs {
+		select {
+		case ch <- m:
+		default: // too slow: cut it off rather than stall the flock
+			delete(ls.subs, ch)
+			close(ch)
+		}
+	}
+}
+
+// Subscribe returns the history after lastID and a channel for what comes next.
+// The channel closes if the subscriber falls too far behind.
+func (h *Hub) Subscribe(listID string, lastID int) ([]sseMsg, chan sseMsg, bool) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	ls := h.lists[listID]
+	if ls == nil {
+		return nil, nil, false
+	}
+	var past []sseMsg
+	if lastID < len(ls.history) {
+		past = append(past, ls.history[max(lastID, 0):]...)
+	}
+	ch := make(chan sseMsg, subBuffer)
+	ls.subs[ch] = struct{}{}
+	return past, ch, true
+}
+
+func (h *Hub) Unsubscribe(listID string, ch chan sseMsg) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	if ls := h.lists[listID]; ls != nil {
+		if _, ok := ls.subs[ch]; ok {
+			delete(ls.subs, ch)
+			close(ch)
+		}
+	}
+}
+
+// Emitter binds the hub to one list.
+func (h *Hub) Emitter(listID string) Emitter { return hubEmitter{h, listID} }
+
+type hubEmitter struct {
+	h  *Hub
+	id string
+}
+
+func (e hubEmitter) Emit(name string, fields map[string]any) { e.h.Publish(e.id, name, fields) }

ledger.go

@@ -123,15 +123,37 @@ func (l *Ledger) Level(crow, taskType string) int {
 	return int(math.Round(w*float64(own.Level) + (1-w)*float64(flock.Level)))
 }
 
+// TrustChange is one level moving up or down. Holder is a crow name or "flock".
+type TrustChange struct {
+	Holder, TaskType string
+	From, To         int
+}
+
 // Judge records a verdict for every crow involved, and once for the flock.
-// The flock needs twice the streak to level up.
+// The flock needs twice the streak to level up. It reports any level changes.
-func (l *Ledger) Judge(crows []string, taskType string, ok bool, promoteAfter int) {
+func (l *Ledger) Judge(crows []string, taskType string, ok bool, promoteAfter int) []TrustChange {
 	l.mu.Lock()
 	defer l.mu.Unlock()
-	for _, c := range crows {
+	var changes []TrustChange
-		get(l.Crows, c+"|"+taskType).apply(ok, promoteAfter)
+	judge := func(holder string, r *Record, need int) {
+		from := r.Level
+		r.apply(ok, need)
+		if r.Level != from {
+			changes = append(changes, TrustChange{Holder: holder, TaskType: taskType, From: from, To: r.Level})
 		}
-	get(l.Flock, taskType).apply(ok, promoteAfter*2)
+	}
+	for _, c := range crows {
+		judge(c, get(l.Crows, c+"|"+taskType), promoteAfter)
+	}
+	judge("flock", get(l.Flock, taskType), promoteAfter*2)
+	return changes
+}
+
+// MarshalSnapshot returns the ledger as JSON, safe to call while lists are flying.
+func (l *Ledger) MarshalSnapshot() ([]byte, error) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return json.MarshalIndent(l, "", "  ")
 }
 
 func (l *Ledger) requester(id string) *Requester {
@@ -144,7 +166,8 @@ func (l *Ledger) requester(id string) *Requester {
 }
 
 // Admit checks a requester at the door: cooldowns, rate cap, and fading grudges.
-func (l *Ledger) Admit(id string, now time.Time, g Guardrails) (bool, string) {
+// When it says no, it returns a prank message and how long the cooldown lasts.
+func (l *Ledger) Admit(id string, now time.Time, g Guardrails) (bool, string, time.Duration) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
 	r := l.requester(id)
@@ -157,7 +180,8 @@ func (l *Ledger) Admit(id string, now time.Time, g Guardrails) (bool, string) {
 		}
 	}
 	if now.Before(r.CooldownUntil) {
-		return false, prank(r.CooldownUntil.Sub(now))
+		wait := r.CooldownUntil.Sub(now)
+		return false, prank(wait), wait
 	}
 	kept := r.Recent[:0]
 	for _, t := range r.Recent {
@@ -167,10 +191,11 @@ func (l *Ledger) Admit(id string, now time.Time, g Guardrails) (bool, string) {
 	}
 	r.Recent = kept
 	if len(r.Recent) >= g.MaxRequestsPerMin {
-		return false, prank(strike(r, now, g))
+		wait := strike(r, now, g)
+		return false, prank(wait), wait
 	}
 	r.Recent = append(r.Recent, now)
-	return true, ""
+	return true, "", 0
 }
 
 func strike(r *Requester, now time.Time, g Guardrails) time.Duration {

main.go

@@ -22,6 +22,8 @@ func main() {
 	switch os.Args[1] {
 	case "run":
 		cmdRun(os.Args[2:])
+	case "serve":
+		cmdServe(os.Args[2:])
 	case "trust":
 		cmdTrust()
 	case "log":
@@ -35,16 +37,12 @@ func usage() {
 	fmt.Fprintln(os.Stderr, `So Many Crows
 
   crows run <todo.txt> [-as name]   hand the flock a todo list
+  crows serve [-addr 127.0.0.1:8080] run the web server (API + SSE)
   crows trust                       show trust ledger
   crows log [-n 20]                 show recent flight log entries`)
 	os.Exit(2)
 }
 
-type itemResult struct {
-	Item, Mode, TaskType, Answer, Verdict, Skipped string
-	Crows                                          []string
-}
-
 func cmdRun(args []string) {
 	fs := flag.NewFlagSet("run", flag.ExitOnError)
 	as := fs.String("as", defaultRequester(), "requester id")
@@ -64,111 +62,73 @@ func cmdRun(args []string) {
 	flog, err := OpenFlightLog(filepath.Join(dataDir, "flight.jsonl"))
 	must(err)
 	defer flog.Close()
-	save := func() {
+	p := &Pipeline{Ledger: ledger, Log: flog, G: g, Approver: &StdinApprover{in: bufio.NewReader(os.Stdin)}}
-		if err := ledger.Save(); err != nil {
-			fmt.Fprintln(os.Stderr, "could not save ledger:", err)
-		}
-	}
 
-	if ok, msg := ledger.Admit(*as, time.Now(), g); !ok {
+	if ok, msg, _ := ledger.Admit(*as, time.Now(), g); !ok {
 		fmt.Println(msg)
 		flog.Write(Event{Kind: "denied", Requester: *as, Note: msg})
-		save()
+		p.save()
 		os.Exit(1)
 	}
 
-	items, err := readTodo(todoPath, g)
+	data, err := os.ReadFile(todoPath)
+	must(err)
+	items, err := parseTodo(string(data), g)
 	must(err)
 	if len(items) > g.MaxItemsPerList {
 		fmt.Printf("That list has %d items. The flock takes at most %d at a time.\n", len(items), g.MaxItemsPerList)
-		save()
+		p.save()
 		os.Exit(1)
 	}
 
 	brain := NewBrain()
-	flock := NewFlock(brain, g, flog)
+	p.Flock = NewFlock(brain, g, flog)
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
 	defer stop()
-	in := bufio.NewReader(os.Stdin)
-	listBudget := &Budget{name: "list", limit: g.TokenBudgetPerList}
 
 	fmt.Printf("Brain: %s · requester: %s · %d items\n", brain.Name(), *as, len(items))
-	flog.Write(Event{Kind: "list", Requester: *as, Note: fmt.Sprintf("%s (%d items)", todoPath, len(items))})
+	l := List{ID: "cli", Requester: *as, Source: todoPath, Items: items}
+	results, listBudget := p.Run(ctx, l, &cliEmitter{items: items, seen: map[string]bool{}})
 
-	var results []itemResult
-	for i, item := range items {
-		fmt.Printf("\n[%d/%d] %s\n", i+1, len(items), item)
-		r := itemResult{Item: item}
-		itemBudget := &Budget{name: "item", limit: g.TokenBudgetPerItem}
-
-		t, err := flock.Triage(ctx, item, itemBudget, listBudget)
-		if err != nil {
-			r.Skipped = "triage failed: " + err.Error()
-			fmt.Println("  " + r.Skipped)
-			results = append(results, r)
-			continue
-		}
-		r.Mode, r.TaskType = t.Mode, t.TaskType
-		fmt.Printf("  Sentry: %s · %s · %s\n", t.Mode, t.TaskType, t.Reason)
-		for _, s := range t.Subtasks {
-			fmt.Printf("    - %s\n", s)
-		}
-		flog.Write(Event{Kind: "triage", Requester: *as, Item: item, Mode: t.Mode, TaskType: t.TaskType, Note: t.Reason})
-
-		// The Sentry earns autonomy on triage separately from the crows' work.
-		triageType := "triage/" + t.TaskType
-		if ledger.Level("Sentry", triageType) < Trusted {
-			ok := confirm(in, "  Approve triage?")
-			ledger.Judge([]string{"Sentry"}, triageType, ok, g.PromoteAfter)
-			flog.Write(Event{Kind: "verdict", Item: item, Crow: "Sentry", TaskType: triageType, Verdict: verdict(ok)})
-			if !ok {
-				r.Skipped = "triage rejected"
-				results = append(results, r)
-				continue
-			}
-		}
-
-		out, err := flock.Execute(ctx, item, t, itemBudget, listBudget)
-		if err != nil {
-			r.Skipped = "flight failed: " + err.Error()
-			fmt.Println("  " + r.Skipped)
-			results = append(results, r)
-			continue
-		}
-		r.Answer, r.Crows = out.Answer, out.Crows
-		fmt.Printf("  Crows: %s\n%s\n", strings.Join(out.Crows, ", "), indent(out.Answer, "  > "))
-
-		// The least-trusted crow involved sets the bar.
-		lowest := Trusted
-		for _, c := range out.Crows {
-			lowest = min(lowest, ledger.Level(c, t.TaskType))
-		}
-		if lowest < Regular {
-			ok := confirm(in, "  Accept this answer?")
-			ledger.Judge(out.Crows, t.TaskType, ok, g.PromoteAfter)
-			r.Verdict = verdict(ok)
-		} else if lowest < Trusted {
-			r.Verdict = "accepted, unreviewed"
-		} else {
-			r.Verdict = "accepted, trusted"
-		}
-		flog.Write(Event{Kind: "verdict", Item: item, Crow: strings.Join(out.Crows, ","), TaskType: t.TaskType, Verdict: r.Verdict})
-		results = append(results, r)
-	}
-
-	save()
 	resultPath := strings.TrimSuffix(todoPath, filepath.Ext(todoPath)) + ".crows.md"
 	must(writeResults(resultPath, todoPath, results))
-	fmt.Printf("\nResults: %s · tokens used: %d/%d\n", resultPath, listBudget.spent, listBudget.limit)
+	fmt.Printf("\nResults: %s · tokens used: %d/%d\n", resultPath, listBudget.Spent(), listBudget.limit)
 }
 
-func readTodo(path string, g Guardrails) ([]string, error) {
+// cliEmitter prints the events a person at a terminal cares about.
-	data, err := os.ReadFile(path)
+type cliEmitter struct {
-	if err != nil {
+	items []string
-		return nil, err
+	seen  map[string]bool
+}
+
+func (c *cliEmitter) Emit(event string, f map[string]any) {
+	if id, ok := f["item_id"].(string); ok && !c.seen[id] {
+		c.seen[id] = true
+		var n int
+		fmt.Sscanf(id[strings.LastIndex(id, "-")+1:], "%d", &n)
+		fmt.Printf("\n[%d/%d] %s\n", n, len(c.items), c.items[n-1])
 	}
+	switch event {
+	case "item.triaged":
+		fmt.Printf("  Sentry: %s · %s · %s\n", f["mode"], f["task_type"], f["reason"])
+		for _, s := range f["subtasks"].([]string) {
+			fmt.Printf("    - %s\n", s)
+		}
+	case "item.answered":
+		fmt.Printf("  Crows: %s\n%s\n", strings.Join(f["crows"].([]string), ", "), indent(f["answer"].(string), "  > "))
+	case "trust.changed":
+		fmt.Printf("  Trust: %s on %s went %s → %s\n", f["holder"], f["task_type"], levelNames[f["from"].(int)], levelNames[f["to"].(int)])
+	case "item.skipped":
+		fmt.Printf("  %s\n", f["reason"])
+	}
+}
+
+var levelNames = []string{"stranger", "regular", "trusted"}
+
+// parseTodo turns todo text (markdown checkboxes, bullets or plain lines) into items.
+func parseTodo(text string, g Guardrails) ([]string, error) {
 	var items []string
-	for _, line := range strings.Split(string(data), "\n") {
+	for _, line := range strings.Split(text, "\n") {
 		line = strings.TrimSpace(line)
 		for _, p := range []string{"- [ ]", "- [x]", "-", "*"} {
 			line = strings.TrimSpace(strings.TrimPrefix(line, p))
@@ -184,24 +144,6 @@ func readTodo(path string, g Guardrails) ([]string, error) {
 	return items, nil
 }
 
-// confirm fails safe: anything but y/yes, including no input at all, is a no.
-func confirm(in *bufio.Reader, prompt string) bool {
-	fmt.Print(prompt + " [y/N] ")
-	line, _ := in.ReadString('\n')
-	a := strings.ToLower(strings.TrimSpace(line))
-	if line == "" {
-		fmt.Println()
-	}
-	return a == "y" || a == "yes"
-}
-
-func verdict(ok bool) string {
-	if ok {
-		return "approved"
-	}
-	return "rejected"
-}
-
 func writeResults(path, source string, results []itemResult) error {
 	var sb strings.Builder
 	fmt.Fprintf(&sb, "# So Many Crows: %s\n\n_%s_\n\n", filepath.Base(source), time.Now().Format("2006-01-02 15:04"))
@@ -211,7 +153,7 @@ func writeResults(path, source string, results []itemResult) error {
 			continue
 		}
 		box := "x"
-		if r.Verdict == "rejected" {
+		if r.Verdict == "rejected" || r.Verdict == "timeout" {
 			box = " "
 		}
 		fmt.Fprintf(&sb, "- [%s] %s\n  - %s · %s · %s · %s\n%s\n\n", box, r.Item, r.Mode, r.TaskType, strings.Join(r.Crows, ", "), r.Verdict, indent(r.Answer, "  > "))
@@ -222,7 +164,6 @@ func writeResults(path, source string, results []itemResult) error {
 func cmdTrust() {
 	l, err := LoadLedger(filepath.Join(dataDir, "ledger.json"))
 	must(err)
-	names := []string{"stranger", "regular", "trusted"}
 	show := func(title string, m map[string]*Record) {
 		fmt.Println(title)
 		keys := make([]string, 0, len(m))
@@ -235,7 +176,7 @@ func cmdTrust() {
 		}
 		for _, k := range keys {
 			r := m[k]
-			fmt.Printf("  %-28s %-9s +%d -%d streak %d\n", k, names[r.Level], r.Approved, r.Rejected, r.Streak)
+			fmt.Printf("  %-28s %-9s +%d -%d streak %d\n", k, levelNames[r.Level], r.Approved, r.Rejected, r.Streak)
 		}
 	}
 	show("Crows", l.Crows)

pipeline.go

@@ -0,0 +1,195 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+)
+
+// Emitter receives the events in EVENTS.md. The web server streams them; the
+// command line prints them. Fields exclude list_id and ts; the emitter adds those.
+type Emitter interface {
+	Emit(event string, fields map[string]any)
+}
+
+// Approval is one question for a human: may this triage or answer stand?
+type Approval struct {
+	ListID, ItemID, Item string
+	Target               string // "triage" or "output"
+}
+
+// Approver asks a human. It returns "approved", "rejected" or "timeout".
+// Anything other than a clear yes is a no.
+type Approver interface {
+	Approve(ctx context.Context, a Approval) string
+}
+
+// List is one todo list handed to the flock.
+type List struct {
+	ID, Requester, Source string
+	Items                 []string
+	Parallel              bool // fly items at once (web); the command line goes one by one
+}
+
+type itemResult struct {
+	Item, Mode, TaskType, Answer, Verdict, Skipped string
+	Crows                                          []string
+}
+
+// Pipeline is the one path every list takes, from the command line or the web.
+type Pipeline struct {
+	Flock    *Flock
+	Ledger   *Ledger
+	Log      *FlightLog
+	G        Guardrails
+	Approver Approver
+}
+
+func itemID(listID string, i int) string { return fmt.Sprintf("%s-%d", listID, i+1) }
+
+// Run flies a list and returns per-item results and the list budget.
+func (p *Pipeline) Run(ctx context.Context, l List, em Emitter) ([]itemResult, *Budget) {
+	listBudget := &Budget{name: "list", limit: p.G.TokenBudgetPerList}
+	items := make([]map[string]any, len(l.Items))
+	for i, text := range l.Items {
+		items[i] = map[string]any{"item_id": itemID(l.ID, i), "text": text}
+	}
+	p.Log.Write(Event{Kind: "list", Requester: l.Requester, Note: fmt.Sprintf("%s (%d items)", l.Source, len(l.Items))})
+	em.Emit("list.started", map[string]any{"items": items, "requester": l.Requester})
+
+	results := make([]itemResult, len(l.Items))
+	if l.Parallel {
+		var wg sync.WaitGroup
+		for i := range l.Items {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				results[i] = p.item(ctx, l, i, listBudget, em)
+			}()
+		}
+		wg.Wait()
+	} else {
+		for i := range l.Items {
+			results[i] = p.item(ctx, l, i, listBudget, em)
+		}
+	}
+
+	p.save()
+	em.Emit("list.finished", map[string]any{"tokens_used": listBudget.Spent(), "token_budget": listBudget.limit})
+	return results, listBudget
+}
+
+func (p *Pipeline) item(ctx context.Context, l List, i int, listBudget *Budget, em Emitter) itemResult {
+	id, item := itemID(l.ID, i), l.Items[i]
+	r := itemResult{Item: item}
+	skip := func(reason string) itemResult {
+		r.Skipped = reason
+		em.Emit("item.skipped", map[string]any{"item_id": id, "reason": reason})
+		return r
+	}
+	w := &itemWatcher{em: em, itemID: id}
+	itemBudget := &Budget{name: "item", limit: p.G.TokenBudgetPerItem}
+
+	t, err := p.Flock.Triage(ctx, w, item, itemBudget, listBudget)
+	if err != nil {
+		return skip("triage failed: " + err.Error())
+	}
+	r.Mode, r.TaskType = t.Mode, t.TaskType
+	p.Log.Write(Event{Kind: "triage", Requester: l.Requester, Item: item, Mode: t.Mode, TaskType: t.TaskType, Note: t.Reason})
+
+	// The Sentry earns autonomy on triage separately from the crows' work.
+	triageType := "triage/" + t.TaskType
+	needTriage := p.Ledger.Level("Sentry", triageType) < Trusted
+	em.Emit("item.triaged", map[string]any{
+		"item_id": id, "mode": t.Mode, "task_type": t.TaskType,
+		"subtasks": nonNil(t.Subtasks), "reason": t.Reason, "needs_approval": needTriage,
+	})
+	if needTriage {
+		v := p.judge(ctx, Approval{ListID: l.ID, ItemID: id, Item: item, Target: "triage"}, []string{"Sentry"}, triageType, em)
+		if v != "approved" {
+			return skip("triage " + v)
+		}
+	} else {
+		em.Emit("verdict", map[string]any{"item_id": id, "target": "triage", "verdict": "auto"})
+	}
+
+	out, err := p.Flock.Execute(ctx, w, item, t, itemBudget, listBudget)
+	if err != nil {
+		return skip("flight failed: " + err.Error())
+	}
+	r.Answer, r.Crows = out.Answer, out.Crows
+
+	// The least-trusted crow involved sets the bar.
+	lowest := Trusted
+	for _, c := range out.Crows {
+		lowest = min(lowest, p.Ledger.Level(c, t.TaskType))
+	}
+	needOutput := lowest < Regular
+	em.Emit("item.answered", map[string]any{"item_id": id, "answer": out.Answer, "crows": out.Crows, "needs_approval": needOutput})
+	switch {
+	case needOutput:
+		r.Verdict = p.judge(ctx, Approval{ListID: l.ID, ItemID: id, Item: item, Target: "output"}, out.Crows, t.TaskType, em)
+	case lowest < Trusted:
+		r.Verdict = "accepted, unreviewed"
+		em.Emit("verdict", map[string]any{"item_id": id, "target": "output", "verdict": "auto"})
+	default:
+		r.Verdict = "accepted, trusted"
+		em.Emit("verdict", map[string]any{"item_id": id, "target": "output", "verdict": "auto"})
+	}
+	p.Log.Write(Event{Kind: "verdict", Item: item, Crow: strings.Join(out.Crows, ","), TaskType: t.TaskType, Verdict: r.Verdict})
+	return r
+}
+
+// judge asks a human, records the verdict, reports trust changes, and saves.
+// A timeout counts as a rejection. A shutdown records nothing.
+func (p *Pipeline) judge(ctx context.Context, a Approval, holders []string, taskType string, em Emitter) string {
+	v := p.Approver.Approve(ctx, a)
+	if ctx.Err() != nil {
+		return "rejected" // shutting down: no human said anything, so record nothing
+	}
+	if v != "approved" && v != "timeout" {
+		v = "rejected"
+	}
+	em.Emit("verdict", map[string]any{"item_id": a.ItemID, "target": a.Target, "verdict": v})
+	for _, c := range p.Ledger.Judge(holders, taskType, v == "approved", p.G.PromoteAfter) {
+		em.Emit("trust.changed", map[string]any{"holder": c.Holder, "task_type": c.TaskType, "from": c.From, "to": c.To})
+	}
+	if a.Target == "triage" {
+		p.Log.Write(Event{Kind: "verdict", Item: a.Item, Crow: "Sentry", TaskType: taskType, Verdict: v})
+	}
+	p.save()
+	return v
+}
+
+func (p *Pipeline) save() {
+	if err := p.Ledger.Save(); err != nil {
+		fmt.Fprintln(os.Stderr, "could not save ledger:", err)
+	}
+}
+
+// itemWatcher turns flock takeoffs and landings into crow events for one item.
+type itemWatcher struct {
+	em     Emitter
+	itemID string
+}
+
+func (w *itemWatcher) Flying(crow string) {
+	w.em.Emit("crow.flying", map[string]any{"item_id": w.itemID, "crow": crow})
+}
+
+func (w *itemWatcher) Landed(crow string, tokens int, err error) {
+	f := map[string]any{"item_id": w.itemID, "crow": crow, "ok": err == nil, "tokens": tokens}
+	if err != nil {
+		f["error"] = err.Error()
+	}
+	w.em.Emit("crow.landed", f)
+}
+
+func nonNil(s []string) []string {
+	if s == nil {
+		return []string{}
+	}
+	return s
+}

server.go

@@ -0,0 +1,255 @@
+package main
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"math"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strconv"
+	"time"
+)
+
+const (
+	maxBody   = 64 << 10 // POST bodies
+	heartbeat = 15 * time.Second
+	webDir    = "web"
+)
+
+// Server is the web front door: the same pipeline as the command line,
+// with web approvals and an SSE hub instead of stdin and stdout.
+type Server struct {
+	p        *Pipeline
+	approver *WebApprover
+	hub      *Hub
+	ctx      context.Context // cancelled on shutdown; lists and streams end with it
+	beat     time.Duration
+}
+
+func NewServer(ctx context.Context, p *Pipeline, approver *WebApprover) *Server {
+	return &Server{p: p, approver: approver, hub: NewHub(), ctx: ctx, beat: heartbeat}
+}
+
+func (s *Server) Handler() http.Handler {
+	mux := http.NewServeMux()
+	mux.HandleFunc("POST /api/lists", s.postList)
+	mux.HandleFunc("GET /api/events", s.events)
+	mux.HandleFunc("POST /api/verdicts", s.postVerdict)
+	mux.HandleFunc("GET /api/trust", s.trust)
+	if st, err := os.Stat(webDir); err == nil && st.IsDir() {
+		mux.Handle("GET /", http.FileServer(http.Dir(webDir)))
+	} else {
+		mux.HandleFunc("GET /{$}", func(w http.ResponseWriter, r *http.Request) {
+			fmt.Fprintln(w, "So Many Crows is listening. The web front end lands in ./web later.")
+		})
+	}
+	return mux
+}
+
+func cmdServe(args []string) {
+	fs := flag.NewFlagSet("serve", flag.ExitOnError)
+	addr := fs.String("addr", "127.0.0.1:8080", "address to listen on (localhost only by default: there is no login yet)")
+	timeout := fs.Duration("approval-timeout", 10*time.Minute, "unanswered approvals count as rejected after this long")
+	fs.Parse(args)
+
+	g := DefaultGuardrails()
+	ledger, err := LoadLedger(filepath.Join(dataDir, "ledger.json"))
+	must(err)
+	flog, err := OpenFlightLog(filepath.Join(dataDir, "flight.jsonl"))
+	must(err)
+	defer flog.Close()
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer stop()
+	brain := NewBrain()
+	approver := NewWebApprover(*timeout)
+	p := &Pipeline{Flock: NewFlock(brain, g, flog), Ledger: ledger, Log: flog, G: g, Approver: approver}
+	s := NewServer(ctx, p, approver)
+
+	srv := &http.Server{Addr: *addr, Handler: s.Handler(), ReadHeaderTimeout: 10 * time.Second}
+	go func() {
+		<-ctx.Done()
+		shut, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		srv.Shutdown(shut)
+	}()
+	fmt.Printf("Brain: %s · listening on %s\n", brain.Name(), *addr)
+	if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		must(err)
+	}
+	if err := ledger.Save(); err != nil {
+		fmt.Fprintln(os.Stderr, "could not save ledger:", err)
+	}
+}
+
+func writeJSON(w http.ResponseWriter, code int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(code)
+	json.NewEncoder(w).Encode(v)
+}
+
+func httpError(w http.ResponseWriter, code int, msg string) {
+	writeJSON(w, code, map[string]string{"message": msg})
+}
+
+// decode reads a size-capped JSON body.
+func decode(w http.ResponseWriter, r *http.Request, v any) bool {
+	r.Body = http.MaxBytesReader(w, r.Body, maxBody)
+	if err := json.NewDecoder(r.Body).Decode(v); err != nil {
+		var tooBig *http.MaxBytesError
+		if errors.As(err, &tooBig) {
+			httpError(w, http.StatusRequestEntityTooLarge, fmt.Sprintf("body over %d bytes", maxBody))
+		} else {
+			httpError(w, http.StatusBadRequest, "body must be JSON: "+err.Error())
+		}
+		return false
+	}
+	return true
+}
+
+func (s *Server) postList(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		Text      string `json:"text"`
+		Requester string `json:"requester"`
+	}
+	if !decode(w, r, &body) {
+		return
+	}
+	if body.Requester == "" {
+		body.Requester, _, _ = net.SplitHostPort(r.RemoteAddr)
+	}
+
+	ok, msg, wait := s.p.Ledger.Admit(body.Requester, time.Now(), s.p.G)
+	if !ok {
+		cooldown := int(math.Ceil(wait.Seconds()))
+		s.p.Log.Write(Event{Kind: "denied", Requester: body.Requester, Note: msg})
+		s.p.save()
+		// Only a list that is still flying can hear about it; otherwise the 429 says it all.
+		for _, id := range s.hub.ActiveLists(body.Requester) {
+			s.hub.Publish(id, "requester.pranked", map[string]any{"message": msg, "cooldown_s": cooldown})
+		}
+		writeJSON(w, http.StatusTooManyRequests, map[string]any{"message": msg, "cooldown_s": cooldown})
+		return
+	}
+	s.p.save()
+
+	items, err := parseTodo(body.Text, s.p.G)
+	switch {
+	case err != nil:
+		httpError(w, http.StatusBadRequest, err.Error())
+		return
+	case len(items) == 0:
+		httpError(w, http.StatusBadRequest, "That list is empty.")
+		return
+	case len(items) > s.p.G.MaxItemsPerList:
+		httpError(w, http.StatusBadRequest, fmt.Sprintf("That list has %d items. The flock takes at most %d at a time.", len(items), s.p.G.MaxItemsPerList))
+		return
+	}
+
+	id := newListID()
+	s.hub.Open(id, body.Requester)
+	l := List{ID: id, Requester: body.Requester, Source: "web", Items: items, Parallel: true}
+	go s.p.Run(s.ctx, l, s.hub.Emitter(id))
+	writeJSON(w, http.StatusAccepted, map[string]string{"list_id": id})
+}
+
+func newListID() string {
+	b := make([]byte, 6)
+	rand.Read(b)
+	return hex.EncodeToString(b)
+}
+
+func (s *Server) events(w http.ResponseWriter, r *http.Request) {
+	listID := r.URL.Query().Get("list_id")
+	lastID, _ := strconv.Atoi(r.Header.Get("Last-Event-ID"))
+	past, ch, ok := s.hub.Subscribe(listID, lastID)
+	if !ok {
+		httpError(w, http.StatusNotFound, "no such list_id")
+		return
+	}
+	defer s.hub.Unsubscribe(listID, ch)
+	flusher, canFlush := w.(http.Flusher)
+	if !canFlush {
+		httpError(w, http.StatusInternalServerError, "streaming unsupported")
+		return
+	}
+
+	h := w.Header()
+	h.Set("Content-Type", "text/event-stream")
+	h.Set("Cache-Control", "no-cache")
+	h.Set("Connection", "keep-alive")
+	h.Set("X-Accel-Buffering", "no")
+	w.WriteHeader(http.StatusOK)
+
+	send := func(m sseMsg) bool {
+		_, err := fmt.Fprintf(w, "id: %d\nevent: %s\ndata: %s\n\n", m.ID, m.Name, m.Data)
+		flusher.Flush()
+		return err == nil
+	}
+	io.WriteString(w, ": caw\n\n")
+	flusher.Flush()
+	for _, m := range past {
+		if !send(m) {
+			return
+		}
+	}
+
+	tick := time.NewTicker(s.beat)
+	defer tick.Stop()
+	for {
+		select {
+		case m, open := <-ch:
+			if !open || !send(m) {
+				return
+			}
+		case <-tick.C:
+			if _, err := io.WriteString(w, ": heartbeat\n\n"); err != nil {
+				return
+			}
+			flusher.Flush()
+		case <-r.Context().Done():
+			return
+		case <-s.ctx.Done():
+			return
+		}
+	}
+}
+
+func (s *Server) postVerdict(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		ItemID  string `json:"item_id"`
+		Target  string `json:"target"`
+		Approve *bool  `json:"approve"`
+	}
+	if !decode(w, r, &body) {
+		return
+	}
+	if body.ItemID == "" || (body.Target != "triage" && body.Target != "output") || body.Approve == nil {
+		httpError(w, http.StatusBadRequest, `need item_id, target ("triage" or "output") and approve (bool)`)
+		return
+	}
+	if !s.approver.Resolve(body.ItemID, body.Target, *body.Approve) {
+		httpError(w, http.StatusNotFound, "nothing is waiting on that verdict")
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (s *Server) trust(w http.ResponseWriter, r *http.Request) {
+	data, err := s.p.Ledger.MarshalSnapshot()
+	if err != nil {
+		httpError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.Write(data)
+}

server_test.go

@@ -0,0 +1,281 @@
+package main
+
+import (
+	"bufio"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestJudgeReportsLevelChanges(t *testing.T) {
+	l, _ := LoadLedger(filepath.Join(t.TempDir(), "ledger.json"))
+	if ch := l.Judge([]string{"Hugin"}, "writing", true, 2); len(ch) != 0 {
+		t.Fatalf("first approval should not change levels: %v", ch)
+	}
+	ch := l.Judge([]string{"Hugin"}, "writing", true, 2)
+	if len(ch) != 1 || ch[0] != (TrustChange{"Hugin", "writing", Stranger, Regular}) {
+		t.Fatalf("want Hugin promoted, got %v", ch)
+	}
+	l.Judge([]string{"Hugin"}, "writing", true, 2) // flock needs 4
+	ch = l.Judge([]string{"Hugin"}, "writing", true, 2)
+	if !hasChange(ch, "flock", Stranger, Regular) {
+		t.Fatalf("want flock promoted, got %v", ch)
+	}
+	ch = l.Judge([]string{"Hugin"}, "writing", false, 2)
+	if !hasChange(ch, "Hugin", Trusted, Regular) || !hasChange(ch, "flock", Regular, Stranger) {
+		t.Fatalf("want both demoted, got %v", ch)
+	}
+}
+
+func hasChange(ch []TrustChange, holder string, from, to int) bool {
+	for _, c := range ch {
+		if c.Holder == holder && c.From == from && c.To == to {
+			return true
+		}
+	}
+	return false
+}
+
+func TestWebApprover(t *testing.T) {
+	w := NewWebApprover(50 * time.Millisecond)
+	if w.Resolve("x-1", "triage", true) {
+		t.Fatal("nothing pending; Resolve should report false")
+	}
+	done := make(chan string)
+	go func() { done <- w.Approve(context.Background(), Approval{ItemID: "x-1", Target: "triage"}) }()
+	for !w.Resolve("x-1", "triage", true) {
+		time.Sleep(time.Millisecond)
+	}
+	if v := <-done; v != "approved" {
+		t.Fatalf("want approved, got %s", v)
+	}
+	if v := w.Approve(context.Background(), Approval{ItemID: "x-2", Target: "output"}); v != "timeout" {
+		t.Fatalf("want timeout, got %s", v)
+	}
+}
+
+func TestHubReplaysHistory(t *testing.T) {
+	h := NewHub()
+	h.Open("L", "r")
+	h.Publish("L", "list.started", map[string]any{"requester": "r"})
+	h.Publish("L", "list.finished", nil)
+	past, ch, ok := h.Subscribe("L", 0)
+	if !ok || len(past) != 2 || past[1].Name != "list.finished" {
+		t.Fatalf("want 2 past events, got %v", past)
+	}
+	past, _, _ = h.Subscribe("L", 1)
+	if len(past) != 1 {
+		t.Fatalf("Last-Event-ID 1 should skip one event, got %d", len(past))
+	}
+	h.Unsubscribe("L", ch)
+	if len(h.ActiveLists("r")) != 0 {
+		t.Fatal("finished list should not be active")
+	}
+}
+
+// sseEvent is one parsed SSE message.
+type sseEvent struct {
+	Name string
+	Data map[string]any
+}
+
+func newTestServer(t *testing.T, g Guardrails, timeout time.Duration) (*httptest.Server, *Server) {
+	dir := t.TempDir()
+	ledger, _ := LoadLedger(filepath.Join(dir, "ledger.json"))
+	flog, err := OpenFlightLog(filepath.Join(dir, "flight.jsonl"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { flog.Close() })
+	ctx, cancel := context.WithCancel(context.Background())
+	approver := NewWebApprover(timeout)
+	p := &Pipeline{Flock: NewFlock(MockBrain{}, g, flog), Ledger: ledger, Log: flog, G: g, Approver: approver}
+	s := NewServer(ctx, p, approver)
+	s.beat = 20 * time.Millisecond
+	ts := httptest.NewServer(s.Handler())
+	t.Cleanup(func() { cancel(); ts.Close() })
+	return ts, s
+}
+
+func post(t *testing.T, url, body string) (int, map[string]any) {
+	resp, err := http.Post(url, "application/json", strings.NewReader(body))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	var out map[string]any
+	json.NewDecoder(resp.Body).Decode(&out)
+	return resp.StatusCode, out
+}
+
+// stream reads events until list.finished, answering approvals with approve.
+// It also reports whether a heartbeat comment arrived.
+func stream(t *testing.T, ts *httptest.Server, listID string, approve *bool) ([]sseEvent, bool) {
+	resp, err := http.Get(ts.URL + "/api/events?list_id=" + listID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	if ct := resp.Header.Get("Content-Type"); ct != "text/event-stream" {
+		t.Fatalf("content type %q", ct)
+	}
+	var events []sseEvent
+	var name string
+	beat := false
+	sc := bufio.NewScanner(resp.Body)
+	for sc.Scan() {
+		line := sc.Text()
+		switch {
+		case line == ": heartbeat":
+			beat = true
+		case strings.HasPrefix(line, "event: "):
+			name = strings.TrimPrefix(line, "event: ")
+		case strings.HasPrefix(line, "data: "):
+			var d map[string]any
+			json.Unmarshal([]byte(strings.TrimPrefix(line, "data: ")), &d)
+			events = append(events, sseEvent{name, d})
+			if d["list_id"] != listID || d["ts"] == nil {
+				t.Fatalf("event missing list_id or ts: %v", d)
+			}
+			needs, _ := d["needs_approval"].(bool)
+			if approve != nil && needs && (name == "item.triaged" || name == "item.answered") {
+				target := "triage"
+				if name == "item.answered" {
+					target = "output"
+				}
+				body := fmt.Sprintf(`{"item_id":%q,"target":%q,"approve":%v}`, d["item_id"], target, *approve)
+				// The approval is registered just after the event; retry briefly.
+				for i := 0; ; i++ {
+					resp, err := http.Post(ts.URL+"/api/verdicts", "application/json", strings.NewReader(body))
+					if err != nil {
+						t.Fatal(err)
+					}
+					resp.Body.Close()
+					if resp.StatusCode == http.StatusNoContent {
+						break
+					}
+					if i > 200 {
+						t.Fatalf("verdict never accepted: %d", resp.StatusCode)
+					}
+					time.Sleep(5 * time.Millisecond)
+				}
+			}
+			if name == "list.finished" {
+				return events, beat
+			}
+		}
+	}
+	t.Fatal("stream ended before list.finished")
+	return nil, false
+}
+
+func count(events []sseEvent, name string) int {
+	n := 0
+	for _, e := range events {
+		if e.Name == name {
+			n++
+		}
+	}
+	return n
+}
+
+func TestServerApproveAndPromote(t *testing.T) {
+	g := DefaultGuardrails()
+	g.PromoteAfter = 2
+	ts, _ := newTestServer(t, g, time.Minute)
+
+	code, out := post(t, ts.URL+"/api/lists", `{"text":"- [ ] What is a crow\n- [ ] What is a rook","requester":"t"}`)
+	if code != http.StatusAccepted {
+		t.Fatalf("POST /api/lists: %d %v", code, out)
+	}
+	yes := true
+	events, _ := stream(t, ts, out["list_id"].(string), &yes)
+
+	if events[0].Name != "list.started" || count(events, "item.answered") != 2 || count(events, "verdict") != 4 {
+		t.Fatalf("unexpected events: %v", events)
+	}
+	promoted := false
+	for _, e := range events {
+		if e.Name == "trust.changed" && e.Data["holder"] == "Sentry" && e.Data["to"] == float64(Regular) {
+			promoted = true
+		}
+	}
+	if !promoted {
+		t.Fatalf("want Sentry promoted; events: %v", events)
+	}
+	resp, _ := http.Get(ts.URL + "/api/trust")
+	var ledger Ledger
+	json.NewDecoder(resp.Body).Decode(&ledger)
+	resp.Body.Close()
+	if ledger.Crows["Sentry|triage/retrieval"].Level != Regular {
+		t.Fatalf("ledger not updated: %+v", ledger.Crows)
+	}
+}
+
+func TestServerTimeoutAndHeartbeat(t *testing.T) {
+	ts, _ := newTestServer(t, DefaultGuardrails(), 100*time.Millisecond)
+	_, out := post(t, ts.URL+"/api/lists", `{"text":"Write a crow poem","requester":"t"}`)
+	events, beat := stream(t, ts, out["list_id"].(string), nil)
+	var v, skipped sseEvent
+	for _, e := range events {
+		switch e.Name {
+		case "verdict":
+			v = e
+		case "item.skipped":
+			skipped = e
+		}
+	}
+	if v.Data["verdict"] != "timeout" || skipped.Data["reason"] != "triage timeout" {
+		t.Fatalf("want timeout verdict and skip, got %v", events)
+	}
+	if !beat {
+		t.Fatal("no heartbeat during a 100ms wait with a 20ms beat")
+	}
+}
+
+func TestServerPrankAndLimits(t *testing.T) {
+	g := DefaultGuardrails()
+	ts, s := newTestServer(t, g, time.Minute)
+	var first string
+	for i := 0; i < g.MaxRequestsPerMin; i++ {
+		code, out := post(t, ts.URL+"/api/lists", `{"text":"Write a poem","requester":"flood"}`)
+		if code != http.StatusAccepted {
+			t.Fatalf("request %d: %d", i, code)
+		}
+		if first == "" {
+			first = out["list_id"].(string)
+		}
+	}
+	code, out := post(t, ts.URL+"/api/lists", `{"text":"Write a poem","requester":"flood"}`)
+	if code != http.StatusTooManyRequests || out["message"] == "" || out["cooldown_s"] != float64(30) {
+		t.Fatalf("want 429 with message and cooldown_s 30, got %d %v", code, out)
+	}
+	past, _, _ := s.hub.Subscribe(first, 0)
+	found := false
+	for _, m := range past {
+		found = found || m.Name == "requester.pranked"
+	}
+	if !found {
+		t.Fatal("requester.pranked not emitted on the active list")
+	}
+
+	// A requester with no list gets only the 429 (nothing to emit on).
+	s.p.Ledger.Requesters["ghost"] = &Requester{CooldownUntil: time.Now().Add(time.Minute)}
+	if code, _ := post(t, ts.URL+"/api/lists", `{"text":"hi","requester":"ghost"}`); code != http.StatusTooManyRequests {
+		t.Fatalf("cooldown should 429, got %d", code)
+	}
+
+	big := `{"text":"` + strings.Repeat("a", maxBody) + `"}`
+	if code, _ := post(t, ts.URL+"/api/lists", big); code != http.StatusRequestEntityTooLarge {
+		t.Fatalf("want 413, got %d", code)
+	}
+	if code, _ := post(t, ts.URL+"/api/verdicts", `{"item_id":"none-1","target":"triage","approve":true}`); code != http.StatusNotFound {
+		t.Fatalf("want 404 for unknown verdict, got %d", code)
+	}
+}