[I work on Claude Code] I broadly agree with the author’s point: 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”. It’s something I came up with late on a Sunday night many months ago, when I got tired of asking Claude to plan with me first before coding in each new session. Something people might not realize is 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 for users.
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 codebase understanding, I sometimes ask Claude to generate an artifact that explains some aspect of its changes. For complex diffs to core parts of the system, I will often ask it to make diagrams or even interactive demos so I can better understand the change and alternatives considered. I don’t do this very often, but it’s a useful way to explain code when you need it. I ask Claude to attach these artifacts to its PRs also, so others can understand and future Claudes have the context.
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 believe spec driven design is a good way to go. But that means keeping all your specs either in the repo (if you want the agent to be able to edit them) or available via for example MCP (if you think only humans should be able to edit them and you got some type of external documentation system keeping specs).
But given that running an agent us cheaper than the cost of waiting for a slot to assemble the team to talk about a change (isn’t it always?), why wait with running the agent?
I propose updating the spec then do the implementation. This will most likely show that a few assumptions were wrong forcing some major or minor updates to the spec. Work through those and then let your team review the spec change together with testing the next iteration of what what’s build.
bcherny · · focus · HN ↗
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”. It’s something I came up with late on a Sunday night many months ago, when I got tired of asking Claude to plan with me first before coding in each new session. Something people might not realize is 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 for users.
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 codebase understanding, I sometimes ask Claude to generate an artifact that explains some aspect of its changes. For complex diffs to core parts of the system, I will often ask it to make diagrams or even interactive demos so I can better understand the change and alternatives considered. I don’t do this very often, but it’s a useful way to explain code when you need it. I ask Claude to attach these artifacts to its PRs also, so others can understand and future Claudes have the context.
locusofself · · focus · HN ↗
tomasGiden · · focus · HN ↗
But given that running an agent us cheaper than the cost of waiting for a slot to assemble the team to talk about a change (isn’t it always?), why wait with running the agent?
I propose updating the spec then do the implementation. This will most likely show that a few assumptions were wrong forcing some major or minor updates to the spec. Work through those and then let your team review the spec change together with testing the next iteration of what what’s build.