用一份 Claude Code 配置把系统提示词从近 50k token 压到约 15k

Claude Code by default gets a system prompt that's almost 50k tokens (measured through my organisational Langfuse proxy). Not every feature is required, or optimal, and can potentially be disabled. Here is what I have, this exact setup is very conservative but works great for me. Your exact setup would be different, so make sure you go through the settings and adapt it for your needs (or ask your agent to do so). This reduces initial system prompt to ~15k tokens.

{ "model": "claude-opus-5-5[1m]", "promptCacheTtl": "1h", "autoCompactWindow": 400000, "enableArtifact": false, "disableWorkflows": true, "disableBundledSkills": true, "feedbackDrafts": "off", "skipDangerousModePermissionPrompt": true, "permissions": { "deny": ["ScheduleWakeup", "ReportFindings", "ListAgents", "AskUserQuestion", "Agent(claude)", "Agent(claude-code-guide)", "Agent(Plan)", "Agent(statusline-setup)", "Agent(test-scenario-definer)"] }, "modelSettings": { "claude-opus-5-5": {"effortLevel": "xhigh"}, "claude-fable-5-1[1m]": {"effortLevel": "high"} }, "env": { "CLAUDE_CODE_SILENT_TURN_REMINDER": "0", "CLAUDE_CODE_TOTAL_TOKENS_REMINDER": "off", "CLAUDE_CODE_TODO_REMINDER_MODE": "off", "CLAUDE_CODE_TOASTY_THIMBLE": "off", "CLAUDE_CODE_THRIFTY_SONIC": "off", "CLAUDE_CODE_SEND_FEEDBACK": "0", "CLAUDE_CODE_ALWAYS_ENABLE_EFFORT": "1", "CLAUDE_CODE_BASH_OUTPUT_AUDIENCE_NOTE": "1" } }

Some specific notes

1. I have my auto compact window set to 400k. This, in my opinion, is optimal for API based pricing. You can remove this line entirely, or set a higher limit. I follow a very spec-driven philosophy and have instructions to write down everything so it works great for me. 400k goes a much longer way when you've optimised your default usage too.
2. Most of the bundled skills are nice to have but hog tokens when I don't need them after day one
3. I don't particularly like plan mode, I still follow plan philosophy however.
4. Artefact is ~18k tokens, Workflows are ~8k tokens, SendFeedback is ~3k tokens. I don't really use any of these, and if I want a workflow I prefer to just script is instead of relying on my harness to orchestrate.
5. I don't really use or recommend plugins like superpowers. I also do not use ultracode, there is nothing that really justifies either in my opinion.

My basic principle is that the latest generation of models have come a long way, and a good harness is one that gives them solid orchestration tools, but gets out of their way. You just need to have good instructions and guidelines.

Of course if you particularly use a feature then just enable it.