dsh-tool-memo

Tool-result memoization for DeepSeek Harness. Idempotent tool calls that repeat with identical arguments are served from a TTL cache instead of re-executing — fewer wasted executions, fewer burned tokens, faster loops.

Plugin id: dsh-memo · npm: dsh-tool-memo

Install

dsh plugin --profile web add dsh-tool-memo
dsh --profile web --dump-config | grep -A3 'id: dsh-memo'   # verify

The plugin ships disabled.

How a hit behaves

| mode | on a cache hit | |------|----------------| | hint (default) | the re-execution is denied with an explanatory reason carrying a bounded preview of the cached value and instructions to bypass with the fresh flag | | inject | EXPERIMENTAL — the verdict additionally carries the full cached result (result field) for harnesses that honor it; on ones that don't, the call simply re-executes |

The fresh flag (default _memoFresh: true in the tool arguments) always bypasses lookup. Mutating and outbound tools (bash, writes, http*, send*, …) are excluded by default — a cached side effect is worse than a repeated one.

Cache semantics

• Key = sha256(tool, stable-serialized args) — content-addressed, safe across sessions of the same profile.
• TTL per tool via perToolTtl globs, defaultTtlMs otherwise; a TTL of 0 disables caching for that tool.
• LRU bounded by maxEntries (default 256); hits refresh recency.
• Error results are never cached.

Config

- id: dsh-memo
  name: dsh-tool-memo
  config:
    enabled: false
    mode: hint                  # hint | inject (inject = experimental)
    defaultTtlMs: 600000        # 10 min
    perToolTtl:                 # first matching glob wins
      - { tool: read_file, ttlMs: 300000 }
      - { tool: "search*", ttlMs: 120000 }
    maxEntries: 256
    excludeTools: []            # empty = built-in mutating/outbound list
    includeTools: []            # empty = all non-excluded tools
    freshFlag: _memoFresh
    audit: { enabled: true }    # default file: <cwd>/.dsh-tool-memo/audit.jsonl

A profile-level patch targeting id: dsh-memo replaces the WHOLE config row (no deep merge) — restate every key you want to keep.

Audit format (JSONL)

{"ts":"2026-09-19T12:00:00.000Z","memo_version":"0.1.0","event":"hit","tool":"read_file","key":"9296…","age_ms":4210}

Events: store · hit · miss · skip (not cacheable / fresh flag / error) · evict.

Development

pnpm install && pnpm --filter dsh-tool-memo test

MIT licensed. Part of the dsh-plugins monorepo.