[FEATURE]: Save plan to file for token efficiency and compaction persistence

[karashiiro]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

I typically start non-trivial tasks in Plan mode and iterate on the plan extensively until it's thorough and matches exactly what I want to build, and then I switch to Build mode to let the agent run on that plan to completion. Unfortunately, this burns a considerable portion of the context window as the Plan agent repeats the entire plan in its context window after every round of iteration.

To make matters worse, after compaction events occur (including during Plan mode itself), large portions of the plan are forgotten, as the compaction summary only has a very low-fidelity version of the plan and occasionally loses track of it entirely. I've worked around this by directing the agent to save the plan to a file in the working directory before beginning any implementations, but that still requires me to manually direct it to read the plan again after most compaction events.

It'd be incredibly helpful if plans were instead saved to some temporary file as part of the Plan mode workflow, and the agent iterated on the plan by modifying it like any other file. For further token-efficiency, the agent could have a built-in tool to display the plan in the UI for review without dumping it into its context again. Then, after compaction events, the agent can have a direction prepended to its compaction summary to read the plan to restore its overall goal, and to continue working on that unless the plan has been fully-completed (this might need another built-in tool to eventually mark the plan as done).

[karashiiro]

I did a few searches and this didn't seem to have already been requested, but FYI the issue triage failed to install OC:

• https://github.com/anomalyco/opencode/actions/runs/20873703654
• https://github.com/anomalyco/opencode/actions/runs/20873703668

[m10rten]

Think this is not something that should be built-in, rather something you can create tools/agents/plugins for to do yourself.

Me personally I have a custom planner agent that writes plans in markdown, gives a summary of tasks/scopes and requires human approval to continue. The planner is a subagent of my main agent, so the main agent only does delegation, keeping context window small. The main agent then knows the tasks and delegates to the builder agent, which executes singular tasks only to avoid noise and ensures 100% completion of each task.

[karashiiro]

I am aware that this could be something custom, but I just don't think it's a very intuitive user experience that a plan can be degraded over time like this due to compaction events. People who run into this shouldn't need to be aware of how compaction works to figure out how to deal with this, and I believe most people who run into this failure mode will chalk it up to the model being incompetent and move on, rather than understanding that it's the consequence of a design decision in OpenCode and that they need to customize it to work around the issue.