Sando

Sando is a local plugin for Claude Code and Codex. It keeps repeated and oversized tool output under control, preserves complete redacted artifacts when they fit the admission limit, and provides bounded local tool surfaces. It runs locally and makes no LLM calls.

Release notes: Sando 0.4.2.

Install the plugin

Install Sando from the host marketplace. Each marketplace source includes its hooks and bundles, so installation needs no build step.

Requirements

• Claude Code or Codex
• Node.js >=22.22.0 <23, with node available in PATH

Check the Node version with:

node --version

Claude Code

Run these commands in Claude Code:

/plugin marketplace add yuzushi-dev/yuzushi-plugins
/plugin install sando@yuzushi

Codex

Add the marketplace:

codex plugin marketplace add yuzushi-dev/yuzushi-plugins

Then open /plugins, select sando, and install/enable it. Start a new session if Codex was already open.

Each host wires only the hooks and MCP surfaces declared by its manifest. The remaining bundled CLI, audit, artifact recovery, proxy, statusline, metrics, and accounting launchers are manual entrypoints. The bundle is self-contained; the optional npm package is not required.

Provider accounting and paired controls

Sando records provider-reported input, cache-read, cache-write, output, reasoning, and turn counts at session stop. It also records mechanical context trimming separately. A weighted token estimate is diagnostic; provider cost and blended rates are shown only when the provider or host reports them.

Run an explicit control session with the plugin still installed:

SANDO_EXPERIMENT=read-heavy \
SANDO_EXPERIMENT_ARM=control \
codex

Treatment sessions use SANDO_EXPERIMENT_ARM=apply (the default). Use the same experiment and optional SANDO_EXPERIMENT_WORKLOAD for both arms. Generate the accounting report from the installed Codex plugin:

/path/to/installed/sando/bin/sando accounting --json

The paired report exposes control/treatment cache classes, output and reasoning tokens, model turns, native/Sando tool calls, mechanical bytes, and billed cost when available. It marks replay results as counterfactual and never turns mechanical reduction into a provider-billing claim.

The statusline shows Sando's context tokens saved and the reduction percentage. A leading ~ marks an estimate; provider-reported savings omit it. Provider token accounting remains available through the accounting report.

Context footprint audit

The read-only audit measures an explicitly captured initial-context body for Claude Code or Codex. It attributes observable bytes to host/project instructions, skills, built-in tools, direct/deferred MCP, Sando, history, prompt, provider overhead, and unknown. It never uses provider totals to invent a category breakdown. If the host body is not exposed, the result is unavailable.

Run it from an installed Codex bundle:

/path/to/installed/sando/bin/sando context audit --host codex --input capture.json --json

The Claude bundle exposes the same command through node context-audit.mjs:

node /path/to/installed/sando/context-audit.mjs context audit --host claude --input capture.json --json

Without a capture it reports the honest boundary:

/path/to/installed/sando/bin/sando context audit --host claude

Capture files use sando-context-capture/v1. They contain byte counts or ephemeral content for classified segments; reports retain only numeric totals and provenance digests, never paths, prompts, or secrets. Mechanical token estimates (ceil(UTF-8 bytes / 4)) and provider-reported usage are separate evidence classes.

Lazy MCP Gateway

Evaluate the explicit Lazy MCP Gateway gate from a redacted, numeric evidence file:

/path/to/installed/sando/bin/sando context gateway-gate --input gateway-evidence.json --json
# Claude bundle: node /path/to/installed/sando/gateway-gate.mjs context gateway-gate --input gateway-evidence.json --json

The evidence schema is sando-progressive-gateway-evidence/v1. The evaluator requires native Tool Search control data, both hosts, ten paired samples and 50 discovery intents per host, isolated original MCPs, unchanged digests, provider-reported metrics, a read-only allowlisted catalog, tested rollback, and the explicit safety/quality thresholds. Missing evidence stays insufficient-evidence; no gateway is enabled by this command.

The evaluator validates the supplied redacted summary structurally; its digest is an integrity checksum, not authentication of provider provenance. A go result is not authorization to build or enable the gateway unless the summary is traced back to the authorized paired runner outputs.

Result progressive disclosure

Large Read, Grep, Bash/log, and MCP results expose a bounded preview plus a sando-result-disclosure/v1 record. The record contains redacted byte counts, provenance, elision markers, and a digest handle; it never contains the full payload. Recover a bounded byte or line range from an installed workspace artifact with:

/path/to/installed/sando/bin/sando artifact get --root . --ref sando:sha256:... --start-line 1 --end-line 40 --json
# Claude bundle: node /path/to/installed/sando/artifact.mjs artifact get --root . --ref sando:sha256:... --json

maxArtifactBytes is an admission limit, not a truncation target. If the complete redacted result exceeds it, Sando keeps only a bounded preview, does not issue an artifact handle, and marks recovery unavailable instead of pretending a partial artifact is complete.

MCP results expose the read-only sando_artifact_get tool for artifacts kept in that MCP process. Claude PostToolUse and Codex artifact paths preserve their existing host boundaries; errors, current results, IDs, order, batches, and binary status remain untouched.

The opt-in provider proxy also emits sando-history-disclosure/v1 metadata for history elisions: each change has digest/byte accounting and explicitly says whether to rerun the tool or use the newer result. Proxy history is not falsely advertised as an MCP artifact.

The Lazy MCP Gateway spike is implemented but disabled by default. It is a replacement surface for explicitly allowlisted external MCP servers, not a wrapper around host built-ins. Configure SANDO_MCP_GATEWAY_CONFIG with JSON (or an explicit JSON file path) containing enabled, allowlist, and servers entries with command/args, then run node packages/sando/gateway.mjs. Do not expose the same MCPs through the host at the same time. Roll back by stopping this process and removing the gateway MCP entry; setting enabled: false is the safe kill switch. No Claude/Codex global configuration is changed by Sando. The production gate remains insufficient-evidence; the current smoke is not evidence of a native Codex Tool Search event or a production go decision.

The spike supports initialize, ping, tools/list, catalog discovery, and allowlisted tools/call through sando_call. Other downstream request paths fail closed; auth, approval, and elicitation are intentionally unsupported and are not propagated.

Optional provider proxy

The plugin also includes the context/history transformer and an explicit proxy launcher for hosts that support a configured local base URL. The proxy is opt-in and leaves Codex transport untouched unless you point the client at its local URL:

SANDO_UPSTREAM_URL=https://api.example.test \
SANDO_CONTEXT_POLICY='{"maxHistoryTokens":1000}' \
/path/to/installed/sando/bin/sando-proxy

Point the provider client at the printed local URL. The proxy records request-level mechanical metrics; provider cost and turn comparisons still come from paired apply/control runs.

For the opt-in F1 footprint record, also set SANDO_CONTEXT_FOOTPRINT_PATH, SANDO_CONTEXT_FOOTPRINT_HOST (claude or codex), and an explicit SANDO_CONTEXT_SESSION_KEY. The record contains no request content; without a session key the initial-context capture is skipped. Set SANDO_PROXY_TRANSFORM=0 when the proxy is used only as a capture front-end. For the local Grafana cockpit, set SANDO_F1_TELEMETRY=1 and send to the loopback-only SANDO_F1_TELEMETRY_ENDPOINT=http://127.0.0.1:4319/v1/logs; only coverage and size buckets leave the capture process.

Project redaction rules

Teams can add project-local detectors in .sando/redaction.json:

{
  "schema": "sando-redaction/v1",
  "rules": [
    { "type": "assignment-key", "key": "DATABASE_URL" },
    { "type": "token-prefix", "prefix": "acme_", "minLength": 24, "maxLength": 128 }
  ]
}

Built-in detectors remain enabled. The supported declarative rules are assignment-key and token-prefix; both use the fixed [REDACTED] placeholder. The profile is loaded from the current project only, and its digest is recorded in receipts. Invalid profiles are reported instead of silently ignored.

Telemetry

Telemetry is off by default. The plugin shows a non-blocking reminder until you make a choice. The optional npm library asks once during an interactive install. See the full disclosure.