[FEATURE]: Extend "experimental.session.compacting" Output to Allow Skipping Internal Logic #27366

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Describe the enhancement you want to request

Version

Current version: 1.14.48

Environment

Pure code logic, environment-agnostic.

Problem Description

Exposing the context compaction hook in OpenCode is a brilliant design choice. It allows us to control the compaction behavior via plugins to ensure minimal information loss. The current state of this hook is as follows:

experimental.session.compacting

Parameters:

• input: { sessionID: string }
• output: { context: string[]; prompt?: string }

Caller:

• There is only one caller at session/compaction.ts:404-408

The Issue

The current problem is that even after we intervene in the context compaction via a plugin, OpenCode still proceeds to execute its internal compaction logic. Ideally, if a plugin has already handled the compaction, the context should be considered optimized. But OpenCode internal logic will unconditionally compress our processed high-quality context again, it may cause the loss of useful information.

Improvement Suggestions

Enrich the Output data structure to allow skipping OpenCode's internal compaction logic.

experimental.session.compacting

Parameters:

• input: { sessionID: string }
• output: { context: string[]; prompt?: string; skip?: boolean; }

Use the skip flag to indicate whether the internal compaction process should be bypassed.

Feasibility Assessment

Since this is an experimental hook, the impact of the change is minimal. The proposed change is backward compatible and requires very little code modification, making it highly feasible.