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Plans Are Disposable, Skills Are Durable

Written by Claude on 2026-07-29, last edited by Claude Fable 5.1 on 2026-09-03 · History · Prompts

The Problem

One of our repos had 135 files in its plans/ directory. Many of them said Status: Implemented or called themselves a “durable record”, and nobody had deleted them because of those labels.

We wrote about our planning skill in February. A plan was a markdown file in plans/, listed in an index, and deleted when the work shipped. After five months of using it across three Hello Weather repos, we could see it covered how to write a plan and not what happens to it afterward. The pile-up brought three more problems with it:

  1. Plans go stale. A plan written in March cites app/models/thing.rb:117. By June that line has moved to 145, the method has a new name, and the library version in the plan is two major versions behind. An agent building from that plan will build the wrong thing without noticing.
  2. Sessions end. The agent that wrote the plan knew the codebase. The agent that implements it three weeks later knows nothing, and may be a smaller model. Anything the plan leaves out, every later reader has to go and find again.
  3. Agents always find something to do. Ask “what’s next?” and an agent will answer. Sometimes the true answer is “nothing, wait for the trigger.” Unless a rule says that answer is allowed, the agent invents work, usually a refactor, and usually the most expensive option available.

We didn’t fix this with a better template. We wrote a policy for the whole life of a plan: what it has to contain, when we delete it, what we keep from it, and what the index is allowed to say.

The Lifecycle

Research → Write (handoff-ready) → Rank in the index → Implement
    → Migrate durable knowledge into a skill → DELETE the plan → Update the index

The policy uses three kinds of document. Most doc rot comes from mixing them up:

Type Lifespan What it holds
Plan One-shot — deleted after it ships This specific change: steps, verified paths, success criteria
Playbook Permanent, versioned A procedure that recurs verbatim per instance
Skill Permanent, versioned A workflow, plus the invariants and gotchas plans leave behind

Playbooks come back at the end of this post. They’re the one thing in plans/ we don’t delete.

Ground Truth: Write for a Reader Who Won’t Explore

Every plan now has a ## Ground Truth section. The planning skill in all three repos states the standard the same way:

Write plans so a less capable model can implement them without exploring the codebase.

If the implementing agent has to grep to find where things register, the plan has failed. A smaller model might grep, guess wrong, and ship the guess. Four rules follow from that.

1. Cite verified paths with line numbers. Here is a real section, verbatim except for the header:

Ground Truth (codebase-verified 2026-06-11)

Key files

File Line Purpose
app/models/api/weather.rb 26-27 Coordinate truncation: truncate(3)

Current implementation

# app/models/api/weather.rb:26-27
@lat = (@args[:lat] || @source_class.default_lat).to_f.truncate(3)

Change required

Change truncate(3) to truncate(2) on both lines.

The skill’s rule is never cite a symbol you haven’t confirmed exists. The header carries the date the paths were checked, so a reader can tell when a citation might have gone stale.

2. Name the registration points. In an unfamiliar codebase, writing the new file is cheap. Finding the four places that have to know about it is expensive. We went through 32 plans in the web repo and added a key-files table to each one. The tables name the constant lists a new entry goes in and the factory method that maps a name to a class. The same pass fixed patterns the plans had made up: a base class that didn’t exist, and an environment-variable lookup where the codebase uses a helper. A plan written from memory invents house conventions.

3. Date every external fact with a Verify: marker. Anything the codebase can’t confirm, such as a library version or a platform deadline, gets flagged where it appears.

| cloud_cover | `cloud_cover` (%) | Recorded; Verify: 0-100 integer encoding per the API spec |
| alert id | Verify: exact key name (`id` vs `alert_id`) | Verify |

The skill’s rule is never present external facts as timeless; date them and flag them for re-checking. The implementation checklist has the agent resolve every Verify: marker before building on it. If a marker is still there at code review, the plan did its job and the implementation skipped a step.

4. Mark what’s cuttable. When a plan feeds a release with a deadline, each item is labeled required or cuttable:

Effort honesty: mark items cuttable vs required when they feed a release block, so time pressure cuts the right things.

Under time pressure, something gets dropped. Whoever drops it usually knows less than the author did, so the author marks it in advance. One release block also ends with a list of things not to do, “Explicitly NOT required for this release (common trap — these feel related but aren’t)”, followed by seven upgrades that look related. Writing that list once is cheaper than having every session rediscover it and argue about it.

One more rule applies when the plan is implemented:

If the plan conflicts with existing patterns — Follow the patterns (AGENTS.md, skills), update the plan.

When the plan and the codebase disagree, the codebase wins.

Deletion: A “Record” Label Is a Delete Signal

The February post said “delete when done.” After 135 files, the rule got more specific:

A plan is removed once the work it describes is fully implemented / shipped, or it is a completed one-time analysis — regardless of what the plan calls itself. A “Status: Implemented”, “implementation record”, “durable record”, or “reference” self-label is not a reason to keep a plan; it is a signal to remove it (after migrating anything durable).

A plan doesn’t call itself a record because it’s valuable. It calls itself a record because someone finished the work and didn’t want to delete the file.

Only three things justify keeping a plan:

  1. Future / unstarted work — not built yet.
  2. Triggered / dormant work — reopens on a monitoring or external trigger, and the plan still holds the live reopen playbook.
  3. An active in-flight decision — pending actions or dates.

Anything else is finished: move out what’s worth keeping, then remove the plan. Being linked from the index isn’t a reason to keep a plan, because the index links to whatever exists. When we’re not sure, the skill says to keep the plan and say why: when uncertain, prefer keep and say why — deleting curated plans is the risky direction.

Migrate before you delete

Durable knowledge a finished plan holds — non-obvious decisions, vendor/API facts and gotchas, operational procedures, hard-won rationale — must be moved into the relevant skill (preferred), or README/AGENTS.md, before the plan is removed. Never keep a plan alive just to hold reference material, and never delete without first rehoming what’s worth keeping.

In the web repo, one pull request removed 35 plans and moved what they held into a dozen skills. We kept the things that still matter after the change ships: three optimizations that didn’t work, so nobody tries them again; quirks in upstream APIs; capacity thresholds and the conditions for reopening them; vendor evaluations we rejected. We deleted the story of how we got there.

We ran the audit with agents. One classified all 135 plans. For every plan marked for removal, a second agent argued the case for keeping it. Then one agent per file did the migration and repointed the links that led to the removed plan. We checked the result with a script rather than by reading:

# Orphans: a plan file the index doesn't point to is a bug
for f in plans/*.md; do
  b=$(basename "$f")
  grep -q "$b" PLANS.md || echo "ORPHAN: $b"
done

An earlier round of deletions had left 15 broken links in the plans that survived, so removal now has a required step before rm:

# Find every plan linking to the one being removed, redirect them in the same commit
grep -rln "plan-name.md" plans/

The Index Is a Ranking Surface, Not a Document Store

PLANS.md had grown to 380 lines, much of it prose copied from the plans. This policy cut it to 240:

PLANS.md is a navigation and ranking surface, not a document store. Duplicated prose goes stale the moment the underlying plan moves.

  • Every entry is 1–3 lines + a link. If you’re writing more than that in the index, the extra belongs in the linked plan.
  • No implemented-work tracking, dated pass logs, or history in the index — record only the current state and what’s remaining.
  • Status updates replace, they don’t accrete. When state changes, rewrite the entry’s current-state line; don’t append another dated bullet under the old ones.
  • Content with no plan doc to link to stays very concise. If it needs more, create the plan doc and link it.

The rule that matters most is “replace, don’t accrete.” An agent updating a status file wants to append, because appending feels safer and keeps the history. It also turns a 3-line entry into a 40-line changelog nobody reads. Dated history is fine inside a plan that’s still in progress, because it goes away with the plan.

The same pass moved each status board next to the procedure it tracks. A multi-step rollout used to tick off progress in the central index. Now the checklist lives inside the runbook, and each rollout PR updates its own line. The procedure and its state are in one document, and the change that moves the work along also updates the state. Before, they were two documents that stayed in sync only if someone remembered.

Every plan also needs a place in the ranking, not just a catalog entry:

Every plan creation/removal MUST update PLANS.md — both the Plan Catalog entry AND its slot in the ranking machinery (a Release block item, a Triggered Work row, or a Not Next row with an explicit reopen condition). A plan that exists only in the catalog has no priority and will never be picked.

The What’s-Next State Machine

The Android index answers “what’s next?” with a fixed five-step check. Step 4 was added the day after this post, when we started using GitHub issues to capture the tangents that come up mid-session:

### What's Next Rule

1. Check **Hard Deadlines** — anything due within ~90 days that isn't
   already in an active release block?
2. Check **Recurring Work** for any row with `Next due` on or before today.
3. Check **Triggered Work** for any fired trigger.
4. List **open GitHub issues** (`gh issue list --state open ...`) —
   unconditional, in every answer; presentation rules in the
   `gh-issues` skill.
5. Otherwise: work the first unchecked item in the lowest-numbered
   **Release** block. If all release blocks are done, this repo is
   idle by design — confirm against the cross-repo index before
   starting anything in **Not Next**.

The second half of step 5 is why the rule exists. The skill spells it out:

If all release blocks are complete, [the repo] is idle by design — check the cross-repo index before proposing anything from Not Next, and say so explicitly rather than inventing work.

“Nothing” is a valid answer, and the rule has to say so in writing, because a model asked for a recommendation will always give one.

The Not Next table keeps deferred work deferred. Every row says what would reopen it:

Work Reopen when
Modernization track (language/DI/toolchain majors) Feature investment reopens, or a required library forces it (none currently does). Order inside the track is fixed by hard dependencies.
Map-rendering rewrite The packaging-compliance check fails (→ jumps into the active release), the vendor SDK breaks or EOLs, or feature investment reopens
Localization Phase 2 (native UI chrome) The platform decision landed and the strings are implemented in open PRs held on a review decision; reopen anything further only after Release 1 ships

A matching rule: never propose Not Next work as next; its reopen condition has to fire first. Without it, “not now” turns into “not now, unless the agent feels like it.”

Triggered and recurring work get their own tables:

## Triggered Work

| Trigger | Action |
|---|---|
| The API ships a new upstream provider | Add it via the integration playbook — small, mechanical, visible product win |
| The packaging-compliance check fails | Escalate the rendering migration into the active release |
| 30 days after Release 1 | Re-triage surviving crash groups; write new plans only if a signature dominates |

## Recurring Work

| Workstream | Cadence | Next due |
|---|---|---|
| Platform compliance check | Annually, every June (deadlines land Aug 31) | 2027-06-01 |
| Crash triage | After each release reaches ~50% rollout; otherwise quarterly | After Release 1 ships |
| Plans index review | After any release or material re-rank | After Release 1 ships |

Both tables answer a question a todo list can’t: is this actionable today, and if not, what exactly would make it actionable? When recurring work is done, the same change updates its Next due date, so the schedule stays in step with the work.

The current answer sits at the top of the index in a What’s Next section. The skill says to recompute it only when a checkpoint arrived, a trigger fired, an issue was added or closed, or the user asks for fresh eyes. Running the full check on every question spends context to get the same answer.

Playbooks: The One Exception to Deletion

One document in the Android plans/ directory is permanent, and it says so:

This playbook stays in plans/ permanently as a living checklist (unlike one-shot plans, it is reused per source, not removed).

It’s the playbook for adding a new upstream data provider to the app. Our server normalizes every provider to one schema, so the client-side work is the same every time. The playbook has:

The test is: will this exact procedure run again, verbatim, for the next instance? If yes, it’s a playbook and it stays. If something like it will run again, the workflow carries over but the steps don’t, and that’s a skill. If it runs once, it’s a plan, and we delete it on merge. A playbook isn’t a plan we decided to keep. Writing a plan and then calling it permanent is how the directory got to 135 files.

Lessons Learned