Files
synapbus/examples/cold-topic-explainer
Algis DumbrisandClaude Opus 4.6 fee73e33a0 feat(ux): run detail page + reaction pills + captured prompt/response
Makes the Web UI reflect what agents are actually doing: reactions
on DMs that trigger a subprocess run, a per-run detail page that
shows the exact prompt the model received and the raw response, and
cross-linked reactive_runs ↔ harness_runs data for a single composite
API call.

Migration 020 (internal/storage/schema/020_harness_run_detail.sql):

  ALTER TABLE harness_runs ADD COLUMN reactive_run_id INTEGER;
  ALTER TABLE harness_runs ADD COLUMN prompt          TEXT;
  ALTER TABLE harness_runs ADD COLUMN response        TEXT;
  CREATE INDEX idx_harness_runs_reactive ON harness_runs(reactive_run_id);

internal/harness:

  * ExecRequest.ReactiveRunID — reactor pins the reactive_runs row id
    so the observer can JOIN the two tables.
  * ExecResult.Prompt / Response — the subprocess harness reads
    prompt.txt / response.txt that wrappers write into the workdir,
    and runs.Store persists them (capped at 32 KiB each).
  * runs.Run struct now has JSON tags — previously the API returned
    PascalCase field names that didn't match the Web UI's snake_case
    TypeScript types.
  * New runs.Store.GetByReactiveRunID for the composite API endpoint.
  * Test schema updated to include the new columns.

internal/reactor:

  * New ReactionNotifier interface + SetReactionNotifier.
  * dispatchHarness now reacts `in_progress` on the triggering DM
    before spawning the goroutine.
  * runHarness reacts `done` on success, `reject` on failure. The
    existing reactionPriority ordering means the terminal reaction
    wins for badge display — no need to remove in_progress first.
  * dispatchHarness sets ExecRequest.ReactiveRunID.

cmd/synapbus/main.go:

  * reactorReactionAdapter: adapts reactions.Service.Toggle to the
    reactor's one-shot AddReaction signature.
  * HarnessRunsStore wired into the API router config.

internal/api/runs_handler.go — GetRun composite endpoint:

  The GET /api/runs/{id} response now returns everything the Web UI
  needs to render the run detail page in one call:

    {
      "run":              <reactive_runs row>,
      "harness_run":      <linked harness_runs row with prompt/response>,
      "agent":            <current agent snapshot with harness_config_json>,
      "trigger_message":  <DM that started the run>,
      "outgoing_message": <first DM the agent produced after startedAt>
    }

  The outgoing-message lookup wraps both sides of the created_at
  comparison in datetime() so SQLite parses the stored 'YYYY-MM-DD
  HH:MM:SS' and the Go-emitted RFC3339 into the same canonical form
  before comparing — a raw string compare was silently returning no
  rows.

internal/api/router.go: HarnessRunsStore field in RouterConfig, wired
through to NewRunsHandler.

examples/cold-topic-explainer/wrapper.sh:

  Writes prompt.txt and response.txt alongside gemini.stdout.raw so
  the subprocess harness can capture "what the model saw" and "what
  the model said" post-hoc.

web/src/lib/components/MessageList.svelte:

  New ReactionPills render below each message body when the message
  carries a `reactions` array (already populated by
  EnrichMessages/ReactionEnricher on the server side). Makes the
  👀 in_progress / ✔ done / ❌ reject lifecycle visible in every DM
  view and conversation.

web/src/routes/runs/[id]/+page.svelte (NEW):

  New run detail page at /runs/:id with sections:

    1. Header strip — agent, status pill, backend badge, trigger
       info, duration, tokens in/out, cost, exit code, trace id.
    2. Triggering message — body + sender.
    3. What the model saw — GEMINI.md / CLAUDE.md from agent snapshot
       + the captured rendered prompt (byte count on each summary
       bar, collapsible details).
    4. What the model said — captured response, falling back to
       logs_excerpt or error_log when unavailable.
    5. Outgoing message — body + recipient + status.
    6. Metadata — reactive_run.id, harness_run.run_id, backend,
       session_id, tokens_cached, k8s_job, agent trigger config.

  Styled against the existing dark tailwind system — no design
  overhaul, fits the current aesthetic (editorial sectioning,
  monospace for code-like content, accent-blue for links,
  accent-purple for system-instructions, accent-green for model
  output, accent-red for errors).

web/src/routes/runs/+page.svelte: the inline expand panel now has
a "View full details →" link next to the Retry button.

E2E VERIFIED on a live subprocess run:

  * Topic: "why does the subprocess harness materialise GEMINI.md
           alongside .gemini/settings.json in the per-run workdir?"
  * 3 subprocess runs + 3 reactive_runs + 3 harness_runs, all linked.
  * message_reactions: 6 rows — in_progress + done for each hop.
  * GET /api/runs/1 returns a composite with
    harness_run.prompt=883 bytes, harness_run.response=550 bytes,
    reactive_run_id=1, trigger_message populated, outgoing_message
    populated (decomposer-pro → writer-flash), agent.gemini_md=747
    bytes. All keys are snake_case as the Svelte types expect.

  Full go test ./... green. `vite build` green. Demo instance still
  running on port 18088 for browser verification.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-14 09:26:18 +03:00
..

cold-topic-explainer

Toy multi-agent task that exercises the subprocess harness end-to-end. Three Gemini agents on different models collaborate via SynapBus DMs to produce a 3-paragraph explainer for a topic, with a writer ↔ critic refinement loop.

Roles

Agent Model Job
decomposer-pro gemini-2.5-pro Receives the topic, splits it into what / why / how, DMs writer-flash
writer-flash gemini-2.5-flash Drafts (or revises) the 3-paragraph explainer, DMs critic-lite
critic-lite gemini-2.5-flash-lite Rates each paragraph 1–10. Scores all ≥ 8 → DMs algis with FINAL:. Else DMs writer-flash with REVISE: and specific fixes

This exercises:

  • Decomposition — decomposer-pro splits one request into 3 sub-questions
  • Delegation — each agent DMs the next, routed by the SynapBus reactor
  • Recursive update — the writer↔critic loop runs until convergence or max_trigger_depth fires (default 6, giving ~3 full refinement rounds)

Every hop is a subprocess reactive run, subject to the same depth / budget / cooldown guards as a K8s reactive run. Each hop writes a harness_runs row with usage, cost, duration, and trace id.

Prereqs

  • gemini CLI installed and authenticated (gemini auth login done once)
  • Go 1.25+
  • jq, curl, sqlite3 available on PATH
  • An unused TCP port (default 18088)

Run it

./start.sh
./run_task.sh "how does the SynapBus reactor's pending_work flag coalesce bursts of DMs?"
./stop.sh

What happens

  • start.sh builds synapbus from the current checkout, launches a separate instance on port 18088 with a local ./data directory, creates user algis (password algis), creates three AI agents, and configures each agent's harness_config_json with GEMINI.md, MCP pointer, role env, and the wrapper script invocation.
  • run_task.sh kicks off the chain by sending an initial DM from algis to decomposer-pro via the admin socket, then polls for a DM to algis whose body starts with FINAL:. Prints the body when it arrives (or gives up after 4 min).
  • stop.sh signals the synapbus PID and waits for it to exit cleanly.

View during the run

OpenTelemetry

Off by default. To ship spans to a collector while you run the task:

SYNAPBUS_OTEL_ENABLED=1 SYNAPBUS_OTEL_ENDPOINT=otel-collector.synapbus.svc.cluster.local:4318 ./start.sh

Or stand up a local collector first using deploy/kubic/otel-collector.yaml. Without a collector, the same information is available in synapbus.log as slog JSON and in the harness_runs table.

Cost

Rough cost per successful run, assuming 2 writer-critic iterations:

Hops Model Cost
1 gemini-2.5-pro ~$0.01
2 gemini-2.5-flash ~$0.01
3 gemini-2.5-flash-lite ~$0.002
Total ~$0.02

The daily trigger budget per agent is capped at 20 (see start.sh) so this example cannot accidentally spend more than pennies per day even if the reactor loops on a bug.

Files

  • start.sh — launch separate synapbus + configure agents
  • run_task.sh — kickoff DM + poll for final
  • stop.sh — graceful shutdown
  • wrapper.sh — shell wrapper used as the agents' local_command; reads message.json, calls gemini, routes the result back via the admin socket
  • configs/*.json — per-agent harness_config_json blobs