agent: add cron-based trigger for scheduled agent runs

[ralphbean]

What happens

Agents can only be triggered by event-driven mechanisms (e.g. issue comments, webhooks). There is no way to run an agent on a recurring schedule.

What should happen

Harness definitions should support a cron-based trigger so agents can run on a schedule (e.g. daily, weekly). The immediate use case is running the scribe agent (#149) once a day, but this would also enable future patterns like:

• Pinging people where attention is needed
• Re-assessing prioritization based on external data sources
• Periodic repo health or activity summaries

Context

Related issues:

• Add secretarial agent to process meeting notes and update the backlog #149 — secretarial agent (first consumer of this feature)
• Decide how agents get triggered: webhooks, polling, or something else #76 — broader trigger mechanism design
• Weekly repo activity summary posted to public Slack channel #150 — weekly repo activity summary (another scheduled use case)

[fullsend-ai-triage]

RICE Priority Score: 0.33

Score breakdown

Dimension	Score	Reasoning
Reach	1	Filed by @ralphbean, who appears to be an internal team member (dogfooding), not a strategic customer. No strategic customers (konflux-ci, openkaiden, guacsec) have requested scheduled agent runs. The feature would eventually benefit all platform users by enabling new automation patterns, but current demand is internal only.
Impact	1	This is an additive capability — it enables new patterns (daily secretarial agents, periodic summaries) but does not fix a broken workflow or unblock anyone. Users can still trigger agents via events today. The improvement is noticeable but not urgent.
Confidence	0.5	The issue is reasonably well-described with clear use cases and linked related issues (#149, #76, #150). However, it is labeled 'type/idea' indicating it is still exploratory, and there is no concrete customer demand signal or milestone assigned. Uncertainty remains around the design scope and actual user demand.
Effort	1.5	Implementing cron-based triggers requires designing the scheduling mechanism, integrating it into the harness definition format, and ensuring reliable execution infrastructure. This touches multiple components (harness config, trigger system, agent runner) and involves some design work, but the scope is bounded by the existing trigger architecture (#76).

Formula: (1 × 1 × 0.5) / 1.5 = 0.33

[fullsend-ai-triage]

🤖 Triage · Started 3:29 PM UTC
Commit: d0ac11b · View workflow run →

[fullsend-ai-triage]

Triage Summary

Category: Feature request · Severity: Medium

Problem

Agents can only be triggered by event-driven mechanisms. There is no way to define a recurring schedule in harness definitions for periodic agent runs.

Analysis

This remains a well-scoped feature request with clear, validated demand:

• Prior art exists: The scribe agent already runs on a cron schedule (Scribe agent: replace cron trigger with event-driven trigger when Gemini notes are available agents#442), confirming the pattern works. That issue tracks moving the scribe away from cron toward event-driven triggers, but the cron infrastructure it uses validates the concept.
• Multiple consumers: Weekly repo activity summary posted to public Slack channel #150 (weekly activity summaries) and Proactive staleness alert for fully-approved ready-for-merge PRs #2004 (staleness alerts) would both benefit from cron triggers, in addition to the use cases listed in the issue body.
• Broader trigger design (Decide how agents get triggered: webhooks, polling, or something else #76): Still open, but cron triggers can be implemented as a specific trigger type within whatever architecture is ultimately chosen. This does not block implementation.
• No duplicate work: No open PRs address cron trigger support.

Recommended Approach

1. Add a schedule/cron trigger type to the harness definition schema
2. Implement scheduling in the dispatch system (likely backed by GitHub Actions schedule events or equivalent per-forge mechanism)
3. Validate cron expressions at config load time with clear error messages
4. Ensure cron-triggered agents receive appropriate context (org/repo info but no issue/PR payload)
5. Coordinate with Decide how agents get triggered: webhooks, polling, or something else #76 for design consistency

Proposed Test Case

Scenario: Cron trigger validation and execution
- Define a harness with cron trigger (e.g., "0 9 * * 1-5")
- Verify cron expression is validated at config load time
- Verify invalid expressions produce clear, actionable errors
- Verify the dispatch system schedules runs correctly
- Verify multiple cron-triggered agents operate independently
- Verify cron triggers coexist with event-driven triggers
- Verify cron-triggered agents receive org/repo context without issue/PR payload

Previous run

Triage Summary

Category: Feature request · Severity: Medium

Problem

Agents can only be triggered by event-driven mechanisms. There is no way to define a recurring schedule in harness definitions for periodic agent runs.

Analysis

This is a well-scoped feature request with clear use cases: the scribe agent (#149, now closed) was the initial consumer, and #150 (weekly summaries) and #2004 (staleness alerts) would also benefit. Notably, fullsend-ai/agents#442 already references the scribe agent running on a cron schedule, which suggests some cron infrastructure may already be in place.

The broader trigger mechanism design (#76) is still open, but that tracks a wider design question. Cron triggers can be implemented as a specific trigger type within whatever architecture is chosen.

Recommended Approach

1. Add a schedule/cron trigger type to the harness definition schema
2. Implement scheduling in the dispatch system using GitHub Actions schedule events or an equivalent mechanism
3. Validate cron expressions at config load time with clear error messages
4. Coordinate with Decide how agents get triggered: webhooks, polling, or something else #76 to ensure the design is consistent with the broader trigger architecture

Proposed Test Case

Scenario: Cron trigger validation and execution
- Define a harness with cron trigger (e.g., "0 9 * * 1-5")
- Verify cron expression is validated at config load time
- Verify invalid expressions produce clear errors
- Verify the dispatch system schedules runs at the correct time
- Verify multiple cron-triggered agents operate independently

---

Labels: Issue already has appropriate type/idea and component/dispatch labels; adding component/harness since the feature requires harness definition schema changes, and priority/medium given the clear use cases but no urgent customer demand.

[fullsend-ai-triage]

🤖 Finished Triage · ✅ Success · Started 3:29 PM UTC · Completed 3:32 PM UTC
Commit: d0ac11b · View workflow run →