Files
deepseek-harness/docs/rfc/proposed/simplification/2026-07-04-prune-write-only-fs-surface.md
Tianyi Cui 774d460889 Expose audited hardcoded tunables as plugin config
The audit swept every packages/*/* plugin for the new AGENTS.md
convention (no hardcoded tunables in plugins) and exposes each finding
as a defaulted, validated Config field. Defaults are the previously
hardcoded values throughout, so no deployment or golden changes.

- tool-fs (had NO Config): readLimit, readMaxLineLength, readMaxBytes,
  readStreamMinSize. The caps thread through ReadToolCaps/ReadWindow —
  read-render already documented that the consumer applies the caps, so
  they become explicit per-request fields.
- tool-web: searchMaxResults (WEB_SEARCH_MAX_RESULTS stays as the
  schemastery default). Also fixes the stale GREP_LIMIT references in
  search.ts and the web-capability-seam RFC (no such constant exists).
- bash-local: graceMs (SIGTERM->SIGKILL escalation grace). The
  RunInternals.graceMs test seam is gone: graceMs is now a required
  SpawnSpec field filled from config, so tests exercise the real
  config path and the defaults live in exactly one place.
- subagent-acp: disposeEofGraceMs / disposeGraceMs. The AcpRunSpec
  fields become required for the same one-defaulting-layer reason.
- session-persistence-sqlite: journalMode ('wal' default; the
  rollback-journal modes serve filesystems where WAL's shared-memory
  files do not work, e.g. network mounts).
- hooks-claude + hooks-codex: stderrSummaryMaxChars for the persisted
  hook/result stderr summary. The duplicated summarize() helpers merge
  into hook-protocol's summarizeStderr(stderr, maxChars), beside the
  HookResultRecord field it feeds, with the bound parameterized the
  same way runHook's defaultTimeoutMs already is.
- compact-basic: charsPerToken for the token estimator (default 4, the
  English-text heuristic; CJK-heavy deployments need ~1-2 or compaction
  fires far too late). Also corrects the BasicCompactService class doc,
  which claimed defaults the required-field config never had.
- fs-local: deletes the dead STREAM_MIN_SIZE constant and the dead
  FsIoInternals.streamMinSize seam — the read-routing bound lives in
  the consumer (tool-fs), where it is now config. This is item 1 of
  the proposed prune-write-only-fs-surface RFC, annotated accordingly.

Every new field gets range validation (following the existing
assertPositiveFinite pattern), a README row, and tests covering the
configured behavior, the schema default, and load-time rejection.
2026-07-04 17:37:23 +08:00

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4.3 KiB
Markdown

# RFC: Prune write-only fields and a dead routing knob from the fs seam
Status: proposed
## Problem
The [fs seam split](../../implemented/simplification/2026-06-26-fsspec-style-fs-seam.md) moved read routing and policy out of the backend into `dsh-tool-fs` and `dsh-fs-policy`. Four pieces of surface kept the pre-split shape — populated on every call, read by nobody:
1. **`STREAM_MIN_SIZE` + `FsIoInternals.streamMinSize` in `dsh-fs-local`** — *already removed by the no-hardcoded-tunables audit (the routing bound became `dsh-tool-fs`'s `readStreamMinSize` config); listed here for the record of the full prune, no work remains.* Originally (`packages/fs/fs-local/src/fsio.ts`, re-exported from `packages/fs/fs-local/src/index.ts`): zero readers anywhere, including fs-local's own source and tests. The backend has no read routing — `readWholeText`/`streamWholeText` are separate primitives the caller chooses between — and the real routing constant lives in the consumer (`packages/fs/tool-fs/src/read.ts`, compared against `info.size`). Two mirrors of the 10 MiB fact; the backend's is dead, and the knob's JSDoc claims a "read routing" override that does not exist.
2. **`FsTarget.inputPath`** (`packages/fs/fs/src/types.ts`): every backend and every test fake must fabricate a "diagnostics only" value with zero production readers — the policy plugin and every error message use `targetKey`/`displayPath`. The `listDir` producer exposes the semantic wobble: directory children get the bare entry name, which was nobody's "input".
3. **`FsEditOutcome.replacements` + `.replaceAll`** (`packages/fs/fs/src/types.ts`): `replacements` has zero production readers (the single-match policy itself stays — it is enforced by the `FS_AMBIGUOUS_EDIT`/`FS_EDIT_NOT_FOUND` throws inside the backend, whose error message keeps the internal count); `replaceAll` is read only by `formatEditOutput` in `packages/fs/tool-fs/src/edit.ts` — as an echo of the `replace_all` argument the tool already holds. Shrunk, `FsEditOutcome` becomes `{ version, before, after }`, parallel to `FsWriteOutcome`'s genuinely backend-discovered fields.
4. **`FileReadOutcome.limit` + `.version`** (`packages/fs/tool-fs/src/read-render.ts`): populated by the read tool, but `formatReadOutput` renders `offset`/`lines`/`totalLines`/`truncatedByBytes` only, and the `fs/observed` emit uses `info.version` directly rather than the outcome copy.
## Proposal
Delete the fs-local constant, its re-export, and the `streamMinSize` knob (the remaining `FsIoInternals` knobs are genuinely used by the atomic-write tests); drop `inputPath` from `FsTarget`; shrink `FsEditOutcome` to `{ version, before, after }` and pass `replaceAll` to `formatEditOutput` from the parsed args; drop `limit`/`version` from `FileReadOutcome`. Update the [filesystem.md](../../../core-data-structures/filesystem.md) pastes, the type-equiv manifest, `packages/fs/fs/README.md`, and the test fakes that currently must fabricate the removed fields.
## Why not keep them?
A future permission/containment layer might want the pre-resolution path for error text — but it would want the *request*, which every call site still holds. "N occurrences replaced" might become model-facing text — a behavior change to design when wanted, and the backend-internal count survives for its error message. A read footer might display `limit` — everything the footer shows already derives from `lines`/`totalLines`. Meanwhile every current and future backend (remote, native) must fabricate wire fields nobody consumes, and every test fake must satisfy them.
## Acceptance criteria
- The removed surfaces are gone — `STREAM_MIN_SIZE`/`streamMinSize` in `dsh-fs-local`, `FsTarget.inputPath`, `FsEditOutcome.replacements`/`.replaceAll`, and `FileReadOutcome.limit`/`.version` — while the request-side `replaceAll` (`FsEditSpec`) and the version fields on the other outcome types are untouched; doc pastes and the manifest in sync; the suite is green with the shrunk fakes.
- `formatEditOutput`'s emitted text is unchanged for both `replace_all` branches, so no snapshot golden churns.
## Risks
The in-flight fs discovery work (glob/grep tools) touches the same `dsh-fs` type files — a textual, not design, conflict; land in either order and reconcile mechanically. Backends gain no new obligations; they shed four.