Compaction and thinking

Compaction

When you run /compact in opencode, the plugin handles it on a short-lived dedicated Claude CLI spawn instead of routing it through your main conversation process. Three reasons:

1. Cost. The summarizer reads your entire transcript every time. Routing through a smaller model keeps /compact from burning your Opus budget.
2. Latency. Claude Haiku 4.5 hits ~150 tok/s with a hard 8k output cap, so compaction completes predictably (~30s for a long transcript).
3. Cleanliness. The compaction spawn skips MCP servers, the tool proxy, and the multi-step continuation hint. It’s a one-shot text-out call; the rest is overhead.

The transcript itself is serialized rich: tool inputs and tool results are both included (each clipped at 10k chars), with oldest entries dropped first when the aggregate exceeds 180k chars. The summarizer sees actual tool activity rather than placeholders.

Picking a different compaction model

Source	How	Wins over
Env var (per-process)	CLAUDE_CODE_COMPACTION_MODEL=claude-sonnet-4-6 opencode	config, default
opencode.json (per-project)	"compactionModel": "claude-sonnet-4-6" under provider.claude-code.options	default
Default	claude-haiku-4-5	–

Anything Claude Code’s --model accepts works as a value.

Extended thinking

The plugin forwards Claude’s thinking blocks (thinking_delta stream events) to opencode as reasoning parts, so the “Thinking” row in the chat panel shows whenever the model uses extended thinking. This works across every Claude 4 family model the CLI supports.

What you see is a summary of the model’s thinking, not the raw chain-of-thought. Anthropic stopped exposing raw thinking on the Claude 4 family and ships a server-generated digest instead. For Claude Opus 4.7 specifically, thinking content is omitted from responses by default; the plugin opts back in by passing --thinking-display summarized on every spawn. Claude Code CLI 2.1.142+ is required for that flag to take effect; older CLIs skip it silently.

Reasoning effort

Each model exposes five picker variants, low / medium / high / xhigh / max. An agent’s own reasoningEffort frontmatter accepts six values: those five plus minimal, which maps to the CLI’s low. The plugin hands the level to the CLI as CLAUDE_CODE_EFFORT_LEVEL at spawn, which Claude Code treats as the session-wide override: it beats the effortLevel in that account’s settings.json and a shell export of the same variable. Effort is fixed for the life of a claude process, so it is part of the session key. Changing effort retires the previous effort’s process and remembered transcript ID before replaying the conversation into a fresh process. Switching back cannot resume stale context; same-effort streaming turns still reuse their process. This reset is scoped to the same directory, model, provider/account, agent, and conversation. If the previous effort still has pending work (including tool results, plan approval, recovery, or /btw), the switch is rejected: finish that work at its original effort first. Title, compaction, and /btw calls do not trigger effort resets.

Earlier versions injected a thinking keyword such as (ultrathink) into the user message instead. Claude Code stopped recognising every keyword except ultrathink, so that path is gone and nothing is appended to your messages any more. Compaction skips request and agent effort overrides, but still inherits a shell-level CLAUDE_CODE_EFFORT_LEVEL when set.

Env-var overrides

The plugin respects the standard Claude Code thinking env vars. If you set them in your shell, they pass through to the spawned process untouched, with the one exception in the first row.

Env var	Effect
CLAUDE_CODE_EFFORT_LEVEL=<level>	Session effort override. Passes through when no effort was requested; a variant or an agent’s reasoningEffort replaces it for that spawn.
CLAUDE_CODE_PROMPT_CACHE_TTL=5m|1h	Prompt cache TTL for the whole machine. Passes through when no agent asked; an agent’s cacheTtl or defaultSubagentCacheTtl replaces it for that spawn.
CLAUDE_CODE_DISABLE_THINKING=1	Disable thinking entirely.
CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING=1	Disable adaptive thinking only.
CLAUDE_CODE_SHOW_THINKING_SUMMARIES=0	Suppress summaries (the plugin sets this to 1 by default when unset).