Stop Over-Prompting Claude: What Its Own Creators Just Taught Us

The Advice That Sounds Like Heresy

At Y Combinator's Startup School this year, Boris Cherny, the creator of Claude Code, gave advice that would have been unthinkable in 2025. He told Claude Code users to delete their CLAUDE.md and their skills every six months, then use the model and add an instruction back only when they see it repeatedly stumble on the same thing.

CLAUDE.md files and skills are the instruction scaffolding that developers wrap around Claude: standing rules and step-by-step procedures. Cherny's point was not that instructions are bad. It was that instructions written for last year's model can actively hurt this year's model. And he was speaking from experience: Anthropic removed more than 80% of Claude Code's own system prompt for models like Claude Opus 5 and Claude Fable 5, with no measurable loss on its coding evaluations. Anthropic also points users to Claude Code's /doctor command to help rightsize their CLAUDE.md files and skills.

You are probably not maintaining a CLAUDE.md file. But if you have been using Claude for legal work since 2024 or 2025, you almost certainly have the lawyer's equivalent: a folder of elaborate prompt templates. And the same shift applies to them.

Why Yesterday's Prompts Hurt Today's Models

The prompting playbook that circulated through the legal profession in 2024 and 2025 was built to compensate for real weaknesses. Models back then skipped steps, so we enumerated the steps. They wrote shallow analysis, so we commanded them to "think step by step." They drifted from the role, so we opened with "Act as a senior partner with 20 years of experience." They missed errors, so we added "double-check your work" to everything.

Each of those compensations targeted a failure that current models largely no longer have. Current Claude models plan multi-step work well without a script, Anthropic says Claude Opus 5 in particular verifies its own work without being told to, and Anthropic's prompting guidance says even a one-sentence role makes a difference, so there is no need for a fictional resume. Anthropic's own guidance for the Claude 5 generation makes the same point: many constraints that were once needed to keep older models out of trouble can now be deleted, letting the model use surrounding context and judgment instead, and overlapping or conflicting instructions force Claude to think harder before deciding what to do. And as Cherny noted, the model reads every instruction every single time you use it. A prompt with twelve numbered steps does not just waste your typing. In our view, it can also produce worse output than a clear statement of the goal, because the model may follow your twelve steps instead of the plan it would have made itself. Anthropic's prompting best practices note, in discussing reasoning, that Claude's reasoning frequently exceeds what a human would prescribe.

Two examples lawyers will recognize:

• "Double-check your work" can now cause over-verification. Anthropic's prompting guide for Claude Opus 5 says the model verifies its own work without being told to, and that explicit re-check instructions compound with that behavior and add cost without improving results. On Opus 5, what was best practice in 2025 is now a tax. For other current models, Anthropic's prompting best practices still recommend asking Claude to check its answer against specific test criteria before it finishes.
• Step choreography overrides better judgment. If your contract-review template marches Claude through steps in a fixed order, the model will generally follow it, even when the document in front of it calls for a different order. In our experience, stating what you need and the constraints that matter, then letting the model plan, tends to work better than the script. Anthropic's prompting best practices make a related point about reasoning: a general prompt like "think thoroughly" often produces better reasoning than a hand-written step-by-step plan, and Claude's reasoning frequently exceeds what a human would prescribe.

What This Does Not Mean

Before you delete your prompt folder, two important cautions. Not everyone took the advice at face value: a response thread on r/ClaudeAI was titled "Opus 5: delete your CLAUDE.md? (no. don't)". For legal work, two objections hold up:

• Deleting everything deletes your context too. Your templates do not only contain incantations. They contain decisions you already made: your jurisdiction, your document conventions, your client-communication standards, the specific caveats your practice area requires. That material is not scaffolding. It is context, and context is exactly what the model still cannot know on its own.
• The advice is a periodic experiment, not a purge. Cherny's actual recommendation is a cycle: delete, use the model on real work, and add an instruction back only when you see it repeatedly stumble on the same thing. That is maintenance hygiene, the same reason you update a form file when the rules change.

The right frame for lawyers: delete the incantations, keep the context.

What to Delete From Your Legal Prompts

Audit your saved prompts for these five categories. They were all reasonable in 2025. They are all candidates for deletion in 2026:

• Elaborate role-play preambles. "Act as a senior partner with 20 years of experience in commercial litigation." A short role still helps: Anthropic's prompting best practices say a role focuses Claude's behavior and tone, and that even a single sentence makes a difference. An invented resume adds little beyond that. Keep the role to a sentence and state the audience and the register you want: "This memo is for a sophisticated client, not a lawyer. Plain English, no hedging."
• Thinking rituals and scripted reasoning. "Think step by step." "Take a deep breath." On models like Claude Opus 5, which run with extended thinking on by default, Anthropic's prompting best practices recommend relying on the model's built-in thinking rather than manual chain-of-thought, and warn that asking the model to write out its reasoning may be declined. A short, general request to think thoroughly about a hard question is fine; Anthropic notes it often produces better reasoning than a hand-written step-by-step plan. What to cut is the ritual phrasing and any template that dictates the reasoning steps.
• Step-by-step choreography for judgment tasks. Numbered procedures make sense where exactly one sequence is safe. For analysis, review, and drafting, state the goal, the constraints, and what done looks like, then let the model plan.
• Redundant verification commands. "Double-check every citation before responding." "Review your answer for errors." On Claude Opus 5, Anthropic says these instructions are redundant and should be removed; for other current models, its best practices still recommend asking Claude to check its answer against specific test criteria. Your verification duty has not gone anywhere, but it lives with you, not in the prompt (more on this below).
• Threat and emphasis inflation. "CRITICAL:", "You MUST", "NEVER, under any circumstances." Anthropic's prompting best practices note that Claude Opus 4.5 and Opus 4.6 are more responsive to the system prompt than previous models, so aggressive language written to fix undertriggering on tools or skills can now cause overtriggering, and recommend dialing it back to normal phrasing. Say what you mean once, at normal volume.

What to Keep (and Even Expand)

Everything the model cannot know without you is worth more than ever, precisely because the model now uses it well:

• The facts of the matter. Parties, dates, procedural posture, what has already happened. More context here has always helped, and still does.
• Jurisdiction and governing law. "Analyze under Florida law" changes the answer. No model update makes this optional.
• Audience and purpose. A demand letter, an internal memo, and a client email need different registers. Say which one you are writing and who will read it.
• Your actual constraints. Word limits, filing requirements, house citation style, the clause positions your firm will and will not accept. These are the load-bearing parts of a good template.
• Confidentiality boundaries. What you have redacted, what stays out of the prompt entirely, and which tier you are on. Our plan-by-plan breakdown covers why client work belongs on commercial data terms.

This is why the shift does not make prompt libraries obsolete. It changes what a good saved prompt looks like: less script, more brief. The best templates in our prompt library were always the ones that carry context (what to provide, what to constrain, what output to require) rather than the ones that choreograph the model's reasoning. If you use our CRAFT framework, note what survives this shift untouched: Context, Audience, Format, and Task are all context. The role-play "R" is the piece to slim down: keep it to a sentence rather than an invented resume.

Your Duties Did Not Shrink

Here is the part of "let the model cook" that does not translate to legal practice. When Anthropic says Claude Opus 5 verifies its own work, it means the model catches and fixes its own mistakes without being prompted. It does not mean the output is verified in the sense your license requires.

Your duty of competence and your duty of candor to the court do not care which model generation you are on. Every citation gets confirmed in a real database before it goes in a filing. Every factual claim gets checked against the record. Every analysis gets your judgment before it reaches a client. Damien Charlotin's AI Hallucination Cases database now logs more than 2,000 decisions in which courts and tribunals addressed AI-hallucinated content, from lawyers and self-represented litigants alike. The fix those cases point to is human verification, not better prompting. Delete the "double-check your work" line from your prompts because it no longer helps the model, not because checking stopped being your job. Our ethics guide covers the full framework.

The Six-Month Retune, Lawyer Edition

Cherny's six-month cadence is worth adopting. Here is our adaptation of it for legal templates: twice a year, run this experiment on your three most-used prompts:

• 1. Save a copy of the current template. You are experimenting, not burning boats.
• 2. Write the minimal version: the task, the context (facts, jurisdiction, audience), the constraints, and the output format. Cut scripted instructions about how to think and how careful to be, and trim any role to a single sentence.
• 3. Run both on the same matter (a closed or hypothetical one) and compare outputs side by side.
• 4. Keep what the comparison proves. If a deleted rule turns out to be load-bearing, add it back in one plain sentence. If the minimal version holds up, the deleted lines were probably not earning their place.

If the minimal version holds up on your matters, you also end up with a template that is far easier to maintain. If you want a starting point for which model to run it on, see our model guide.

FAQ

Do lawyers still need prompt templates in 2026?

Yes, but their job has changed. A good template is now a context-carrier: it reminds you what facts, jurisdiction, audience, and constraints to provide, and pins the output format you need. Templates that script the model's reasoning step by step are the ones that have aged badly.

Should I stop telling Claude to double-check its work?

On Claude Opus 5, yes. Anthropic's guidance for Claude Opus 5 says the model verifies its own work without being told to, and that explicit re-check commands add cost without improving results. For other current models, Anthropic's prompting best practices still recommend asking Claude to check its answer against specific test criteria. Either way, your own verification of citations, facts, and analysis remains mandatory. That duty belongs to you, not the prompt.

What is CLAUDE.md and why is everyone talking about deleting it?

CLAUDE.md is an instruction file developers use with Claude Code, Anthropic's coding tool. Its creator advised deleting it every six months as an experiment, because instructions written for older models can constrain newer ones. The lawyer's equivalent is the elaborate prompt template: same logic, same experiment worth running.

Does minimal prompting mean shorter prompts overall?

Not necessarily. Cut instructions about how to think and behave, but context should stay and often grow. The balance to aim for is more facts and fewer rules: the relevant context the model cannot know on its own, with instructions kept to what you actually need.

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