> This worked well for a while, until a few months ago, using early versions of Fable, I realized that I wasn’t using plan mode anymore because the model just got it, and because for the increasingly complex work I asked the model to do, planning had become interactive and iterative. With Opus 5.5, I feel Opus has gotten to that point too.

For me it’s actually the opposite, and Claude Code’s plan mode isn’t nearly sufficient. Personally I ask Claude to write down a markdown file with its plan, then review the plan using plannotator, and then go back and forth (most of the time it’s actually the comments that are the problem, not the code).

Then start a fresh session, seed it with the plan, tell Claude to find ambiguities / friction points / oversights, resolve those, and then implement it.

Review once again with plannotator, go back and forth, and then send PR.

Maybe not the “vibe coding” that was once imagined, but this does ensure I am fully aware of the code and architecture, the quality, and this also prevents long term degradation.

It's useful because it let's me see the decisions the model will make before it wastes a ton of time implementing them. The model is smarter now but that doesn't solve for underspecification if it guesses my intent wrong

Plan mode is critical in the beginning, because there's a lot of long tail decisions that haven't been considered, let alone resolved.

But as skills and memory are populated over time, Plan mode isn't as necessary. It becomes simpler to let Claude just build and get something general in place that works, and then refine from there. Auto mode will ask essential questions.

I still use Plan mode for big feature changes, to confirm that I've asked for what I want in the right way. I tend to prompt casually, with only a few specific details. Plan mode helps me see the whole picture before committing. In a few cases, it also helped me decide the feature I asked for was wrong.

I realize there are already a ton of comments, but I think you're missing the idea of _precision_.

Most people aren't precise when initially describing their problem.

Jumping straight into implementation skips the part where we refine and better define what it is we're trying to do, and think through the implications of those changes.

I suspect "trusting the model" doesn't really work at scale with finite resources.

Fascinating! I literally never use Claude without plan mode and I find it's basically useless without it, constantly wasting tokens going in circles on irrelevant things. Fable or Opus. I feel like neither has a good sense for how to architect things and if I don't use plan mode it usually wastes hours of time chasing it's tail or implementing kludges on kludges to get something working that would be a much simple fix elsewhere, especially when working on a larger codebase.

I've had Claude generate me videos of before & after to better convey new features or bugfixes, that's been quite helpful.

In case anyone else is interested, the skill is public: https://github.com/Mudlet/Mudlet/blob/development/docs/demo-...

So my Claude Code workflow for a ticket is:

* Scoping discussion - do research and figure out approach (auto mode)

* Planning - take the scoping and convert it to a concrete plan for review (plan mode)

* Implementation - put the plan into action (auto mode)

I find this works really well for my workflow, and it is really easy to trigger each phase because the model has clean boundaries. (This workflow is articulated in my user CLAUDE.md) Plan mode is still useful to me as it forces the model to double-check its plans (I find even with Opus 5.5 it still discovers gaps), and it gives me an opportunity to clear context at a really good spot.

So I would still consider plan mode to be useful. It would make me sad to see it go.

PS- I have a Claude Marketplace directory submission for an MCP server that has been sitting in review hell for six(!) months. I've never received any outcome other than "In Review". I hope I'm not asking too much but would it be possible to put me in touch with someone who might be able to help here. Nobody has ever replied to messages sent to mcp-review@anthropic or the "Anthony at Platform Operations" inquiring about status, and we are getting frustrated

hi I’m the author of the post. I think that’s basically the distinction I’m trying to make.

Historically, plan mode served two different roles:

1. making the agent’s instructions precise enough to execute 2. helping the human understand what was about to happen

I think #1 is less necessary as agents get better. #2 is going the other direction, it becomes more important as the model is able to do more on its own because larger chunks of work are happening with increasing complexity.

Where I’ve changed my mind is the interface for #2. I increasingly think an interactive, iterative workflow is closer to how people actually build understanding than being handed a long generated document, especially one they didn’t author themselves.

The human-understanding problem is very real though

> In Claude Code, all plan mode does is add a little reminder to every user message

I was quite surprised when I learned this (when Claude Code edited a file despite being in plan mode). I had previously assumed "plan mode" was a harness level concern, and restricted what tools could be used. I didn't expect that it was simply an addendum to the prompt.

But I think it gave me some good insight into where the heads are at of Anthropic employees building this. Basically, leaning on pushing everything to the model. That's why alignment is so important: a "sufficiently advanced" model doesn't require any tooling infrastructure around it, and I suppose Claude Code devs are targeting that future. I had previously thought there was more to a harness, but with "auto" mode these days, it seems like there's no desire to build in that direction.

It seems unsurprising that if your definition of "plan mode" is as tiny as appending "but don't write code yet", that it would not be that useful for that long. There have to be more sophisticated versions of what "plan mode" means out there.

Also if you are working in a heavily vibe-coded codebase, as Claude Code reportedly is, it's not that surprising if the human doesn't really understand it or have anything useful to add in a collaborative context.

Good to hear, this is my experience also:

I haven't reached for Plan Mode in awhile--maybe, on some blank folder/canvas and I just want that cute "questionnaire" DX to get me going...

But on the whole, CC is smart enough to know when to "rush off and act" and when to "pushback", which is great--and it's no big deal to tell it to pause/stop by adding "what's your thoughts?" or "feel free to pushback" etc to my prompts to make it start a back-and-forth with me (the fact that you say that Plan Mode was really nothing more than a prompt anyways is reassuring).

And yeah, when you're deep in the weeds, you could (and can!) have multiple threads of thought/work going on in the same convo, that stopping and starting a plan in Plan Mode seems like a regression.

(happily using Claude Code Opus 5.5 on High rn)

Well that explains why I was able to coax it to partially execute on some things without actually exiting plan mode.

I disagree with the assertion that the model gets it. Here’s a practical example I just tried with Fable 5.1. I gave it this prompt: “Write a Go function that can be used to establish secure communication to a remote system using a certificate. Keep it short, single function, and explain how to use it.” The output forced the use of a private key stored in a file even though that wasn’t specified anywhere as a requirement. The function Claude wrote takes a private key file argument and calls a Golang function that requires a private key file (tls.LoadX509KeyPair) even though Go has crypto.Signer which could support private keys in various other manifestations like HSM or KMS. I argue that a person who “gets it” (or who is reasonably experienced in security) would have opted for not requiring private key material for this to work.

For the record, this isn’t unique to Claude. ChatGPT and Gemini do the same, each with its own quirks. ChatGPT got extra credit for being the only one who allowed the function to also take a CA file for server authentication.

Don’t get me wrong: LLMs are the future (maybe even the present) of software development but I think there’s some way to go before they can be entirely hands-off in some areas. I still find myself having to course correct designs and plan mode helps me with that.

And of course, thank you for your work on Claude. :)

I get the idea here, but I find planning very useful as a phase when I'm doing things I am not intimately familiar with (e.g. AppKit programming).

That's when I need to learn about implied patterns, do's and don'ts; not from theory but in the context of my own project. Unfortunately, the model tends to keep implicit knowledge implicit. But I can ask during planning.

The feature did get less useful over time when the model started babbling in newspeak more and more. When it threw a thousand words at me even in concise mode.

So I don't want to let the toolmakers off the hook here. There's a lot to win that would make plan mode much much better without changing plan mode itself.

> plan mode was useful, and is no longer useful.

> In Claude Code, all plan mode does is add a little reminder to every user message along the lines of “you’re in plan mode, please don’t code yet"

Can't help but think if plan mode isn't useful as you say because it's implementation is lacking in claude code, hypothetically speaking.

What I can say is that with other harnesses plan mode helps stabilize my workflows. Actually synthesizing code is only part of the process, lots involved in taking a work-item to production end-to-end and plan mode helps give this flow structure. More than that it's an opportunity to regroup before committing to changes. It slows down the process to a rythim that's sustainable and smooth, which ends up speeding up the process.

So if plan mode in claude was designed to speed up code churn, while oh my pi for instance designed plan mode to be strategic, that might account for the different perceptions here.

And it's not to say you should force yourself to use it, but if you are planning on cutting this mode off the loop just beware of the possible side effects.

I would have agreed a few months ago before opus 5 but I'm back to plan mode and lots of the old tricks trying to get that insolent model to follow instructions. 5.5 so far is better but certainly doesn't feel under my control (had it go off and read other repos and make changes just yesterday while in "plan mode").

To be honest the new behavior is convenient when I just say "X is broken, please fix". But I find myself more and more adding "please do not do anything yet, just tell me what you would do" and please feel free to ask if anything is unclear", especially if is making decisions that are a fork in the road.

I would really like a dry run mode that just disables all external commands from the outside so Claude doesn't proactively go about changing things.

What I do nowadays, for large changes, is have Fable create a HTML explainer for what we're gonna do with code snippets, which is not that fat from plan mode only much more convenient for me and modern models have no issue using that HTML artifact as the source of truth, and then before I get into execution - I interactively build an end to end test that also includes pieces of the plan.

When a test case fails, the relevant part of the plan is surfaced in the error. I find this helps Claude stay on track for longer - I've been able to do 12h most times and even up to 48h unattended (11h of API time) with good results.

Then whenever I do check in, I ask it to update the HTML with current state in an append only fashion (sort of like it's writing a blog), and then based on that, we iterate on the end to end test (I think of it as a "test harness") - update the test cases and error messages.

I've been able to build some truly large projects this way, both greenfield and up to spec (for example, a video game I've always wanted to play), and brownfield while staying within the conventions and design of the codebase, and with very little attention required on my part.

> plan mode has always been a prompt — it has never changed the toolset because doing so would break the prompt cache, and so would be expensive

seems like plan mode could turn off some tools, even if it doesn't change the set offered to the model, the ones that they have which would mutate your codebase could just not work with an error message, and plan mode could change permissions in the security approval prompt for "auto"

anyway, isnt the right way to know if plan mode helps or not, to run an experiment? we're all guessing unless we have data

read only agent mode sounds straightforward and useful to me

for me it basically all boils down to:

1. I dont want to have to accept every time Claude touches our DB

2. I'm scared out of my mind it might do something bad to the DB

Plan mode gives me enough confidence that it wont do (2) --> allowing me to give it enough permissions to do (1)

Early versions of plan mode would erase the chat history and present the plan as the start of a new session when you approved it.

I miss that. It worked really well, and it kept the context clean.

I am not seeing this and I’m wondering why. Maybe how I plan is different then you? Maybe what we each mean by plan is different? Maybe you trained yourself to write more effective prompts than old you? Maybe the problems you’re solving don’t need planning and the problems I’m solving do? Maybe I’m pickier about solutions?

Plan mode was great, but I realized I progressed well beyond it. I found that I was getting these categories repeated errors and oversights from Claude (and frankly it hasn't gotten much better about this). Skills were too generic and got lost to context.

I ended up building out tool an MCP server that I use as a bit of a psuedo harness for Claude. I have a variety of multi-step workflows that are basically micro-skills stacked on top of each other. This helps me make sure that I can get Claude to think in a repeatable and reliable manner.

For coding, I've found that I have a few specific steps that Claude needs to do before I'm comfortable letting it loose:

* It must extensively explore the code base (including certain areas that it misses)

* It must think about what it doesn't know or is making assumptions about

* It MUST scaffold out it's intentions. Essentially, it can write comments, classes, and method stubs - but no actual content. Very much like a spec, but since it's in and alongside other code, it's much easier to identify problems.

* It must spike and validate key assumptions. This, plus the prior step, are the only way I've figured out how to avoid it ending up in a confusion loop. Too often it looks at poor-quality code it's written and thinks it's a long-term solution. By avoiding writing code as much as possible, it knows that it's draft content.

* Only, then can I review it and send it it.

Said MCP server (missing the actual ops): https://github.com/clops-mcp/clops-mcp

I frequently ask claude to write and review org-mode files. I've found it useful to maintain knowledge decisions both for claude and myself. Less so for other members of my team who wont use emacs or (n)vim. But thought I'd share.

Yeah I think this is a natural consequence of longer task horizons. When I was chaining 4h tasks, I can mostly plan them up front.

Now that I’m frequently designing and delegating day/week scale features, the flow has to change; having the agent go off and build a spike can be a quicker way of us understanding the design space and constraints (especially in a huge codebase). I still have the agent write and update a spec doc as I go, but it’s not waterfall anymore.

At least for my kinesthetic learning mode a rough code PR stack is usually way better than a plan doc anyway, and tokens are cheap enough (vs my time) that going further than just a plan is often cost-effective overall.

The dream of course is (say it with me) loops, but that doesn’t tend to work for me on new features often.

Honestly I don't agree with this. A few reasons why I feel like I will always want a plan mode:

1. I want to know whats going to happen, at least at a high level, before changes are actually made. 2. Plan mode helps me flesh out the missing details of my plan before being mid-execution 3. In situations where I have a limited budget for AI usage I will often times use a high powered model like Opus 5.5 or Fable to make a detailed plan, then scale down to a cheaper model for implementation. I feel like this saves cost in the end.

I get plan mode is basically just a small hidden prompt. I get that I can basically just preface my prompts with "make a plan only, don't make actual changes." Maybe this is just a UX trick, but it works well for my brain.

Plan mode is what makes it easy for me to update my mental model of the codebase, and helps me decide if the mental overhead of all the changes that are needed are even worth doing, which are now the biggest limiting factors (reading the code diffs just doesn’t scale anymore).

> It’s something I came up with late on a Sunday night many months ago

Aider, Cline and many other agents had plan mode before Claude Code existed.

> planning had become interactive and iterative

I find myself endlessly ctrl+c ing claude now as it flies off doing deep first principles analysis to work out how to find a thing it isn't sure about but I know the answer. Being able to give it that answer without needing to ctrl c would be a massive improvement

I'm not an Anthropic model user, and the true frontier of the frontiers is beyond my budget. Maybe it's better in the rarefied atmosphere of Astra, Fable and Opus 5.5?

But with GPT 5.6 Sol, I'm still finding that the model makes conceptual mistakes, or gets edge cases wrong, or assumes incorrectly (making an ass out of both user and model). In many cases, I need to at least refine the proposed approach, or amend, correct, or flat out just stop and start over. Not planning and catching these errors, and just letting the agents code their code, would mean I'd have to rollback and redo many times. What a waste!

For a current project, which is ~33k lines of code, I'm also finding that I know the codebase better than the model, and that's vital at the planning stages too. If I wasn't in the planning loop, the model would have reinvented various wheels a few times over. How much spaghetti do you want with your code?

As always, I may simply be doing this wrong. But I'm personally not convinced that the plan is dead, or that I want the plan to be dead. Planning is also good for me -- it keeps me thinking about the code, prompting better, guiding the model better.

If I'm no longer on top of the codebase, then at some point my prompts will devolve to "Do the thing with the thing, that does thing". And I don't want that.

what worked for me is a frontend driving the agent, capturing every user message, every commit, every pull request, putting them in a graph (uses a frontend because I didn't want to load a coding agent with tools + responsibility of book keeping) and the agent get tools to search reason behind code changes and see the high quality user input underneath instead of the sloppy self written justifications

I don't really use plan mode, but I do have Fable write a lot of docs, particularly when the work involved is long and multistep, because I may need to do it across multiple sessions.

Oh I thought it blocked tool calls like editing files...

You don't need to actually change the tool schema or break the prompt cache to do that. In the tool itself you could just check if it's in plan mode and reject the tool call...

As someone that never used the built-in plan mode, but did use a lot of spec-driven development, I’m still finding that even with Fable having “plan” docs is still quite helpful.

They’re most useful for broad changes (new features, refactors, etc.) where it’s helpful to avoid breaking changes or unnecessary scope expansion.

The new models are great, but they do more by default, which means I’m finding myself explaining what _not_ to do more often than with previous models (where they’d often end too early).

In my case, the previous plan mode was too ephemeral, and I like having one source of “truth” that sits across context windows without loss/compaction.

I m a bit surprised by this as - during the last 2 months - I 've encountered more often models going ahead of what I have asked from them. It's gotten so annoying that now instead of just saying "Let's plan X" I will also say, "Stop once you 've written the plan." because otherwise there is a distinct (~35% anecdotally) probability that the model will go ahead and implementing the plan as well. [This applies to both Anthropic and OpenAI models btw.]

Plan mode is a useful shortcut when I want to have an agent do read-only work without having to worry about giving it appropriate stop conditions.

I was thinking of making (locally) an “artifact mode” along those same lines. It’s a much better way to see proposed changes

I like plan mode personally. I only use claude code for the web, and the questions claude asks me to clarify are usually pretty important - mostly because I was too vague or contradictory in my prompt, or what I was asking for conflicted with something else in the code. I don't know how claude would resolve that without plan mode.

Also for session planning, as in when-can-I-walk-away-from-computer, its nice to know the particular rhythm of initial crunch - ask questions - make plan - do it. Especially with a 5 minute cache timeout.

I created a skill "feasibility", which is basically "evaluate feasibility of this idea and propose solution options". So I can check that Claude's idea of how to implement the requirement is close enough to my own before it starts working. It is a lot more lightweight than plan mode, because the skill says not to build a detailed plan, just a high-level summary.

My team has been struggling to understand whether or not we should do "spec-driven" development or not. It makes a lot of sense to me to have one developer iterate with the model/harness to generate a markddown document that is a high-level of what will be implemented, and then have the team PR review it before and agent attempts to do the actual implementation work. Do you think this is a good practice?

I keep forgetting that CC has access to the "question" tool, even outside plan mode, which is mostly why I still use it sometimes. This isn't (or wasn't until recently) the case for Codex.

I just tell Claude to write an md file and do research first anyway… makes sense

Thanks for the context, and makes sense a lot. That’s my primary reason to use plan mode.

However how about decisions? Do we expect the model to read our minds, just assume the best practice will be followed and that’s what the user want? Plan mode solves those, what is that am I missing?

I urge you to have a look at tools like tuicr and hunk. It’s a missing component in the chat. I really want a proper chat interface, leave comments on the code and have them replied to. No clue how to implant it tho, it’s a hard UX problem IMO

I always append something along the lines of “evaluate”, “investigate” or “report only” to my prompts when I want to see what the agent is gonna do. Because especially with the new models they tend to go easily off rail and do stuff I didn’t ask. To say that they just “get it” is highly dependent on the task, scope and blast radius.

> it has never changed the toolset because doing so would break the prompt cache, and so would be expensive for users.

It could still make the tools into no-ops or disabled if it actually tries to use them, without changing the context history at all.

Yeah, as a user I came to the same conclusion as I naturally used plan mode less and less over time.

I still use plan mode in Astra to come up with a plan that I then feed into Fable. I feel like OpenAI models still do better big picture investigation and planning, while Claude is the better software engineer, if that makes any sense.

Of course this could well come down to my own biases and the specific things I’m working on.

I’m always telling the model “don’t write code yet” so I maybe ill try plan mode if it’s just a prompt change

Reading the replies, it's interesting how idiomatic everything is, eh? We must all opine about our specific setups, panes, prompts, and how they're the true way, or the true alternative to plan mode.

I really wonder what I’m missing because my general rule to plan first unless explicitly instructed works perfectly fine with all models I use.

“I want to ...” / “Let’s ...” -> Plan

“Do X” -> Actually Act.

But then again I also have it configured to only ever answer questions instead of inferring them to be instructions (which I’ve seen others do differently).

that's the problem though: - LLM now output good enough results without a plan.. for coding at least. I'm not saying amazing results..just good enough. it works fine.

- Most people suck at planning anyway

- LLM still don't give you a way to verify and understand to iterate.. you have to ask and then formulate and way so people barely do it, they just trust the vibe

IMO the current successor to plan mode should be the harness knowing when to tell the use "ok here's our overall current state in a simple diagram", auromatically