description: 'Use when working in the deepseek-harness repo to find non-obvious simplification candidates, write proposed Agent Notes or inline TODO/FIXME/XXX notes, audit or coalesce superseded Agent Notes, or fold worthwhile simplification ideas from another PR; especially for dead, duplicated, speculative, over-built, added-then-removed, or hand-rolled-where-a-dependency-exists surfaces.'
This skill helps turn a broad "find things to simplify" request into evidence-backed Agent Notes that remove or collapse existing harness surface area. It is guidance, not a checklist: follow the code, keep judgment active, and prefer a few well-proven candidates over a pile of thin guesses.
- Read `AGENTS.md`, especially the pre-release stance and the conventions (including the tests-are-not-golden-truth and Agent Notes-are-not-golden-truth doctrines), plus [docs/defensive-patterns.md](../../../docs/defensive-patterns.md) and [docs/testing.md](../../../docs/testing.md).
- Skim [docs/architecture.md](../../../docs/architecture.md) before judging anything under `packages/`; simplifications that fight the service map or event taxonomy need extra evidence.
- Use the Agent Note tree and its [contract](../../notes/README.md) to understand intentional architecture. The most relevant implemented examples are [drop mutable session summary](../../notes/implemented/simplification/2026-06-19-drop-mutable-session-summary.md), [shared persistence write coordinator](../../notes/implemented/architecture/2026-06-18-shared-persistence-write-coordinator.md), [capability seams](../../notes/implemented/architecture/2026-06-13-capability-seams.md), and the twin adapter / dual persistence backend Agent Notes.
- Treat dual LLM adapters and dual persistence backends as intentional by default. Do not propose deleting either twin/backend as "low effort" unless the user explicitly overrides that constraint. Removing an unused method or hook inside a protected seam can still be valid if it does not collapse the protected design.
## What Counts As A Strong Candidate
A strong simplification removes, folds, or demotes something real and has clear evidence that the current shape costs more than it buys:
- A public method, event, config knob, registry notification, helper, package, durable event, or test artifact has no production consumer.
- Tests or docs are the only consumers, and the behavior they pin is not load-bearing.
- Two representations mirror the same fact, especially across durable session events and transient `agent/*` events.
- A seam has methods every implementation must support but no consumer uses.
- A package boundary exists only for test/demo/support code and adds publish or dependency overhead.
- A feature implements speculative product generality: multi-session/session-load, background task rosters, live registry invalidation, mid-turn steering, tool-owned UI rendering, and similar shapes with no product owner.
- Hand-rolled code reimplements what a well-maintained external package or a Node builtin at the engine floor already provides, and the swap would delete the implementation plus its dedicated tests ([dependency policy](../../notes/implemented/process/2026-07-26-dependencies-over-hand-rolling.md)).
Thin candidates are usually not enough for an Agent Note: deleting one typo, running `knip` once, removing an intentionally documented backend/adapter, or flagging "this looks complex" without call-site proof.
- ACP automation and human UI surfaces: prompt settlement and teardown on the protocol side; transcript rendering and interaction state on the UI side.
Start with the largest production-code deltas. A broad simplification audit that stops after obvious unused symbols can miss the files where duplicated lifecycle or defensive machinery carries most of the cost.
## Audit Trust And Lifecycle Boundaries
Classify every defensive copy, freeze, validator, and callback capture by the boundary it crosses. Same-process typed service/plugin calls ordinarily borrow readonly values; parser/config, queue, model/tool JSON, durable/file, worker, process, and wire boundaries own or validate data. Tests built around hostile getters, fake typed objects, callback replacement, or mutation after a same-process handoff are evidence of a potentially speculative contract, not automatic justification for keeping it.
For complex asynchronous code, draw the ownership graph and map each sentinel, readiness promise, cancellation path, disposer, and state flag to a distinct owner or transition. When several mechanisms mirror the same liveness or settlement fact, propose one transaction or lifecycle controller instead. Preserve separate machinery where it protects a real boundary: synchronous publication and rollback, callback containment, first-terminal-outcome arbitration, worker/process ownership, or dispose-to-quiescence.
Introducing a dependency is a valid simplification move, not a policy exception: the [dependency policy](../../notes/implemented/process/2026-07-26-dependencies-over-hand-rolling.md) owns the bar. When surveying, ask of protocol parsers, framers, retry/backoff loops, glob matchers, diff engines, and similar infrastructure: does a well-maintained npm package or a Node builtin at the repo's engine floor already do this?
Prove a dependency-swap candidate like any other, plus:
- Read the hand-rolled implementation and name the exact surface the package covers; residual semantics the package does not cover count against the swap and stay in the Agent Note.
- Check the package's health honestly (maintenance, adoption, transitive footprint) and prefer builtins when the engine floor has them.
- Check the Agent Note tree first: schemastery, vendored Cordis, the twin adapters, and other recorded seams are settled — a swap that collapses one needs to beat the recorded rationale, not just cite the policy.
- Weigh net deletion: implementation plus dedicated tests plus docs, minus the glue that remains. A wrapper that relocates the same complexity is not a win.
- Ambiguous corpus: examples and scripts that may be product smoke paths. Inspect usage before classifying.
Use `rg` first. Good searches include the exact symbol, event name, package name, config key, method name with both `.name(` and `name(`, and any wire strings. Then read the call sites. `knip` can help, but it is not a substitute for understanding public interfaces, dynamic event names, tests, docs, and Cordis loader paths.
Reject or downgrade a candidate when:
- A production caller exists and the simplification would be a feature decision rather than a cleanup.
- The removal would force unrelated churn without actually making the contract smaller.
- The idea is correct but tiny. Add a targeted TODO/FIXME/XXX instead, using the urgency semantics in [docs/development.md](../../../docs/development.md).
Audit the Agent Note tree when the user asks to reduce or coalesce it, or when the simplification being implemented makes an owning note obsolete. Do not expand every code-simplification survey into a repository-wide note audit.
Use [`dsh-archive-agent-notes`](../dsh-archive-agent-notes/SKILL.md) for retention judgment and archive mechanics. Low-future-value implemented notes move as frozen triplets to `archived/{kind}`; proposed notes are never archived; rejected notes that no longer prevent a tempting mistake are deleted. Do not edit an archived note while simplifying current prose or code.
Follow the deletion rule in the [Agent Note contract](../../notes/README.md#when-to-write-one); do not duplicate or weaken it here. For each candidate chain:
1. Identify the current owner from shipped code, configuration, generated catalogs, package docs, newer Agent Notes, and inbound links; dates and titles are discovery hints, not proof.
2. Classify the old note as fully or partially superseded. Any surviving behavior, current contract, durable format, compatibility obligation, or independently current rejected alternative makes it partial. Rationale that can be transferred to the current owner does not by itself make supersession partial.
3. For full supersession, move every unique rationale, alternative, consequence, shipped verification contract, and named coverage gap into the current owner. An inventory that only describes deleted implementation mechanics is not one of those decision facts.
5. Search exact filenames, symbols, config keys, event names, and wire strings after the edit. Keep partial supersessions cross-linked and current.
An added-then-removed feature is a common full-supersession case. Let the removal note own the history only when the feature is absent from production code, configuration, schemas, durable or wire formats, migration, and compatibility behavior; no current documentation presents it as available; and no test exercises it as supported behavior. Removal rationale and tests that enforce absence may remain. Preserve why the feature originally existed, why that motivation no longer justified it, alternatives to full removal, the capability given up, conditions for reintroduction, and evidence that removal is complete. Old tests and implementation mechanics that verified only the deleted behavior are not current verification contracts.
Reject consolidation when the removal is only one transport, default, implementation, or presentation of a feature; when persisted data or compatibility handling survives; or when the removal note does not yet carry enough rationale to prevent accidental reintroduction. A current negative design decision may legitimately need its own note even though the removed implementation is gone.
Create one file per durable proposal under `.agents/notes/<lifecycle>/<class>/yyyy-mm-dd-topic.md`, following the lifecycle/classification contract in `.agents/notes/README.md`. Keep prose paragraphs on one physical line and use relative Markdown links.
-`## Problem`: name the current surface, cite the relevant files, and state the consumer evidence. Separate production callers from tests/docs.
-`## Proposal`: say exactly what to remove, fold, demote, or rehome. Include tests, docs, READMEs, JSDoc, event-taxonomy, snapshot, and generated-file cleanup when relevant.
-`## Why not keep it?` or `## What we give up`: make the strongest counterargument legible.
-`## Acceptance criteria`: observable end state and gates.
-`## Risks`: public API changes, behavior changes, future product wants, and why the tradeoff is still reasonable.
Be concrete enough that an implementing PR can follow the trail. Avoid vague "simplify this package" Agent Notes. When a proposal overlaps an existing Agent Note, consolidate the useful details into the existing one rather than creating a duplicate.
For docs-only Agent Note work, run at least `pnpm run doc-sync`, `pnpm run lint`, and `git diff --check`. For code comments or skill changes, also run the relevant validator when one exists. Select any other evidence from the outgoing diff; the pre-push hook contributes typecheck only.
For each consolidation group, name the old and current owners, state the evidence for full supersession, and explain why deletion is safe. If an added-then-removed scan finds no qualifying note, report that result and the representative partial cases retained.
