refactor: move dynamic editor context from system prompt to user message by markijbema · Pull Request #6225 · Kilo-Org/kilocode

markijbema · 2026-02-24T12:01:09Z

Motivation

PR #6151 added editor context (active file, visible files, open tabs, shell, timezone) to the system prompt <env> block. However, the system prompt is built once per session and cached — putting dynamic information like active file and open tabs there means the model sees stale data as the session progresses.

This matches the pattern used by the legacy VS Code extension, where getEnvironmentDetails() is called before every agent turn.

Changes

Split editor context into static and dynamic parts:

Static → System prompt (cached)

Context	Why static
Today's date (`toDateString()`)	Only changes once per day
User timezone	Rarely changes
Default shell	Rarely changes

Dynamic → User message (per-turn)

Context	Why dynamic
Active file	Changes as user switches editors
Visible files	Changes as user opens/closes files
Open tabs	Changes as user opens/closes tabs

Dynamic context is injected as a synthetic <environment_details> text part on each user message, so the model always has fresh context.

Files changed

packages/opencode/src/kilocode/editor-context.ts — Split editorContextEnvLines() into staticEnvLines() + environmentDetails()
packages/opencode/src/session/system.ts — Use staticEnvLines for system prompt
packages/opencode/src/session/prompt.ts — Inject environmentDetails() as synthetic part on user message

Split editor context into static and dynamic parts: - Static (system prompt, cached): date, timezone, shell These rarely change and benefit from prompt caching. - Dynamic (user message, per-turn): active file, visible files, open tabs These change frequently as the user switches files/tabs. Injected as a synthetic <environment_details> block on each user message so the model always has fresh context. This matches the pattern used by the VS Code extension, where getEnvironmentDetails() is called before every agent turn.

The model didn't know to look for or use the <environment_details> block injected into user messages. Add a static instruction in the system prompt explaining it, similar to how the legacy VS Code extension does it. This instruction is static text that never changes, so it caches well alongside the rest of the system prompt.

kilo-code-bot · 2026-03-17T14:06:03Z

Code Review Summary

Status: 1 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	0
WARNING	1
SUGGESTION	0

Issue Details (click to expand)

No new issues found in the incremental diff.

Other Observations (not in diff)

Issues found in unchanged code that cannot receive inline comments:

File	Line	Issue
`packages/opencode/src/kilocode/editor-context.ts`	13	Removing `editorContext.timezone` drops explicit user timezone context and changes the generated SDK/OpenAPI request schema, which can break typed callers that still send that field.

Fix these issues in Kilo Cloud

Files Reviewed (1 files)

packages/opencode/src/session/prompt.ts - 0 issues

_{Reviewed by gpt-5.4-20260305 · 167,687 tokens}

…on across turns

…ment_details

Compute environmentDetails() once per turn and reuse across tool-loop steps so the last user message stays byte-identical, preserving prompt cache hits on subsequent steps.

…-loop Key the cached envBlock by lastUser.id so that when a new user message arrives while the tool loop is still running, environment details are recomputed with fresh editor context instead of reusing stale data.

Copy editorContext from the original user message onto the synthetic summary message created after task.command, so environment_details are not lost when lastUser switches to the synthetic message.

…tails Replace parts.push() with a shallow copy of the message object so the original message from storage is never mutated. This prevents duplicate environment_details blocks from accumulating across tool-loop iterations.

chrarnoldus · 2026-03-18T11:11:36Z

+        // kilocode_change start
+        ``,
+        `At the end of each user message, you may receive <environment_details> with information about the user's currently active file, visible editors, and open tabs. This is auto-generated context — use it to understand which files the user is working with.`,
+        // kilocode_change end


How did you verify including this in the system prompt is beneficial?

Co-authored-by: Christiaan Arnoldus <christiaan.arnoldus@outlook.com>

The injected TextPart for environment details was missing id, sessionID, and messageID fields required by the MessageV2.TextPart type.

Analyzes recent PRs merged March 13-20 that could cause the CLI to lose conversation history mid-session. Identifies PR #6225 (move dynamic editor context to user message) as the most likely culprit due to token inflation from environment_details injection triggering premature context compaction.

…ext-to-user-message refactor: move dynamic editor context from system prompt to user message

github-actions Bot added the contributor label Feb 24, 2026

markijbema force-pushed the mark/move-dynamic-context-to-user-message branch from d88a6c8 to 2d8d49b Compare February 26, 2026 13:19

Mark IJbema added 2 commits March 17, 2026 15:00

markijbema force-pushed the mark/move-dynamic-context-to-user-message branch from 2d8d49b to f46b733 Compare March 17, 2026 14:01

markijbema marked this pull request as ready for review March 17, 2026 14:02