writing-workspace-signals

name	writing-workspace-signals
description	Authors Friday workspace signals with correct provider configs, payload schemas, and runtime wiring. Use when creating or editing signals in workspace.yml; when a signal needs to accept user input from the Run dialog; or when signal validation or runtime dispatch fails.

Writing workspace signals

Checklist

• description present (required)
• provider matches exact enum: http, schedule, system, fs-watch, slack, telegram, whatsapp, discord, teams
• Provider config present and valid
• HTTP signals with params: schema declared with type: object, properties, required
• HTTP config.path unique across workspace
• Schedule config.schedule valid cron
• Signal referenced by at least one job trigger (or dead_signal warning)
• No id inside inline job fsm: — runtime injects from job name

Two foot-guns

Schemaless signals with payload params

No schema → Run dialog renders no input fields → payload arrives empty. Job gets {} instead of the params it expects.

Wrong:

signals:
  draft-reply:
    description: "Draft a reply"
    provider: http
    config:
      path: /draft-reply

Right:

signals:
  draft-reply:
    description: "Draft a reply to an email"
    provider: http
    config:
      path: /draft-reply
    schema:
      type: object
      properties:
        message_id:
          type: string
        instructions:
          type: string
      required:
        - message_id

id inside inline FSM blocks

Runtime auto-injects id from job.name. Adding your own risks mismatch.

Wrong:

jobs:
  review-inbox:
    fsm:
      id: review-inbox-job   # don't

Right:

jobs:
  review-inbox:
    fsm:
      initial: idle

Wiring HTTP signals to external systems

A provider: http signal exposes a URL but does NOT tell upstream systems (Bitbucket / GitHub / Jira) to call it. The user still needs to register the webhook on the upstream side. The /hook/raw/{workspaceId}/{signalId} URL pattern, the /status discovery flow, signal-schema requirements, and the tunnel-level error catalog all live in [[wiring-external-webhooks]] — load that skill any time the user asks how to "set up the webhook", "wire Bitbucket/GitHub/Jira", or why /status is unreachable. The HTTP signal in workspace.yml is necessary but not sufficient.

Templates

HTTP trigger, no payload

signals:
  triage-now:
    description: "Triage unread emails immediately"
    provider: http
    config:
      path: /triage-now

HTTP trigger with payload

signals:
  draft-reply:
    description: "Draft a reply to a specific email"
    provider: http
    config:
      path: /draft-reply
    schema:
      type: object
      properties:
        message_id:
          type: string
        tone:
          type: string
      required:
        - message_id

Cron trigger

signals:
  daily-scan:
    description: "Triage inbox every morning at 9am"
    provider: schedule
    config:
      schedule: "0 9 * * *"
      timezone: "America/Los_Angeles"
      # Optional: what to do with firings the daemon was down for.
      # Defaults to manual — surfaces a pending row in /schedules,
      # operator decides. All non-skip policies are bounded by
      # missedWindow (default 24h) so a long outage can't produce
      # an unbounded burst.
      onMissed: manual        # default; other options: skip | coalesce | catchup
      missedWindow: 24h       # optional; default 24h

onMissed policies:

• manual (default) — surface the missed slot on the /schedules UI as a pending row; do not auto-fire. The operator clicks "Fire now" or "Dismiss". Right for jobs with expensive or visible side effects (paid API calls, email blasts, Slack posts) where you want oversight without auto-replay. Default since 2026-05-03 — silent drops surprised users.
• skip — drop missed firings entirely. Pick this when missing slots is a non-event because the next scheduled fire will pick up where it left off (e.g., "fetch latest prices" — recency is implicit in the next fire).
• coalesce — fire once now to represent every missed slot inside missedWindow. Payload carries policy: "coalesce", missedCount, firstMissedAt. Right for "did this happen recently?" jobs (digests, syncs) where one make-up call covers the gap.
• catchup — fire each missed slot in chronological order, one signal per slot, payload tagged policy: "catchup". Right for "every tick must run" jobs (rate-limit accruals, time-series ingest, slot-numbered exports). Use when missing a slot is incorrect, not just late.

missedWindow (Duration: s/m/h, default 24h) caps the catch-up window for every policy. A daemon down for a week with catchup on an hourly cron only fires the slots inside the window — never all 168.

Missed-schedule events surface on the playground /schedules page under "Missed schedules" and persist in the JetStream WORKSPACE_EVENTS stream for 30 days. manual events that haven't been fired/dismissed show a pending badge + action buttons.

Concurrency policy

concurrency controls what happens when a new envelope for the same (workspace, signal) arrives while a previous cascade is still running. Orthogonal to onMissed (which is the downtime catch-up policy). Lives on every signal provider, not just schedule.

signals:
  send-alert:
    provider: schedule
    config:
      schedule: "*/5 * * * *"
      concurrency: skip   # default; other options: queue | concurrent | replace

Policies:

• skip (default) — drop the new envelope if a cascade is in flight for this (workspace, signal). Right for cron jobs where the next tick will run anyway and you don't want pile-up if cascades exceed the schedule.
• queue — serialize: chain the new envelope after the current one in arrival order. Right when every tick must eventually run; risks unbounded backlog on slow cascades.
• concurrent — no overlap guard, full parallelism. Right for stateless / idempotent jobs that benefit from parallel runs (independent fetches, fan-out scrapes).
• replace — abort the in-flight cascade and start the new one. Right for "freshest input wins" workloads (cancel-in-flight semantics for non-chat signals).

For HTTP-trigger correlated callers, skip and replace publish ok=false on the response subject immediately so callers don't wait out their HTTP timeout. queue blocks the caller until the in-flight cascade settles. concurrent returns each cascade's own response.

System trigger

signals:
  workspace-ready:
    description: "Fired when workspace runtime finishes init"
    provider: system

Validation error decoder

Code	Fix
invalid_type on description	Add description field
invalid_type on config.path	HTTP signals need config.path (string, unique)
invalid_type on config.schedule	Schedule signals need config.schedule (valid cron)
http_path_collision	Make each HTTP path unique
cron_parse_failed	Fix cron; use crontab.guru
dead_signal	Add a job trigger or delete the signal

Runtime anti-patterns

• Schema not type: object. Run dialog reads properties. Bare string schema or missing properties = no fields rendered, empty payload. Symptom: dialog says "trigger immediately" when it should ask for inputs. Fix: add type: object, properties, required.
• Payload type mismatch. Schema says string, caller sends number → signal fails with 500, session never starts. Fix: prefer string for IDs even if they look numeric.
• HTTP path collision. Two signals same config.path → first one wins, second unreachable. Fix: unique paths per workspace.
• Missing timezone on cron. Defaults UTC. 9am PST becomes 5pm. Fix: explicit timezone.

Order of declaration

Signals last — nothing depends on them. But declare schema before you test the signal. A signal without schema may pass validate_workspace yet fail at runtime when the Run dialog sends {} to a job expecting fields.

Assets

• assets/minimal-http-signal.yml — trigger, no payload
• assets/http-signal-with-schema.yml — trigger with typed form fields
• assets/schedule-signal.yml — cron trigger with timezone