lossless-claw

Lossless Context Management plugin for OpenClaw, based on the LCM paper from Voltropy. Replaces OpenClaw's built-in sliding-window compaction with a DAG-based summarization system that preserves every message while keeping active context within model token limits.

Table of contents

• What it does
• Quick start
• Configuration
• Commands And Skill
• Documentation
• Development
• License

What it does

Two ways to learn: read the below, or check out this super cool animated visualization.

When a conversation grows beyond the model's context window, OpenClaw (just like all of the other agents) normally truncates older messages. LCM instead:

1. Persists every message in a SQLite database, organized by conversation
2. Summarizes chunks of older messages into summaries using your configured LLM
3. Condenses summaries into higher-level nodes as they accumulate, forming a DAG (directed acyclic graph)
4. Assembles context each turn by combining summaries + recent raw messages
5. Provides tools (lcm_grep, lcm_describe, lcm_expand) so agents can search and recall details from compacted history

Nothing is lost. Raw messages stay in the database. Summaries link back to their source messages. Agents can drill into any summary to recover the original detail.

It feels like talking to an agent that never forgets. Because it doesn't. In normal operation, you'll never need to think about compaction again.

Commands And Skill

The plugin now ships a bundled lossless-claw skill plus a small plugin command surface for supported OpenClaw chat/native command providers:

• /lcm shows version, enablement/selection state, DB path and size, summary counts, and summary-health status
• /lcm backup creates a timestamped backup of the current LCM SQLite database
• /lcm rotate rewrites the active session transcript into a compact tail-preserving form without changing the live OpenClaw session identity or current LCM conversation
• /lcm doctor scans for broken or truncated summaries
• /lcm doctor clean shows read-only high-confidence junk diagnostics for archived subagents, cron sessions, and NULL-key orphaned subagent runs
• /lcm status shows plugin, conversation, and maintenance state including deferred compaction debt
• /lossless is an alias for /lcm on supported native command surfaces

These are plugin slash/native commands, not root shell CLI subcommands. Supported examples:

• /lcm
• /lcm backup
• /lcm rotate
• /lcm doctor
• /lcm doctor clean
• /lossless

Not currently supported as root CLI commands:

• openclaw lcm
• openclaw lossless
• openclaw /lcm

The bundled skill focuses on configuration, diagnostics, architecture, and recall-tool usage. Its reference set lives under skills/lossless-claw/references/.

Quick start

Prerequisites

• OpenClaw with plugin context engine support
• Node.js 22+
• An LLM provider configured in OpenClaw (used for summarization)

Install the plugin

Use OpenClaw's plugin installer (recommended):

openclaw plugins install @martian-engineering/lossless-claw

If you're running from a local OpenClaw checkout, use:

pnpm openclaw plugins install @martian-engineering/lossless-claw

For local plugin development, build your working copy first, then link it instead of copying files:

cd /path/to/lossless-claw
pnpm build

openclaw plugins install --link /path/to/lossless-claw
# or from a local OpenClaw checkout:
# pnpm openclaw plugins install --link /path/to/lossless-claw

Re-run pnpm build after local source changes so the linked plugin's dist/ output stays current.

The install command records the plugin, enables it, and applies compatible slot selection (including contextEngine when applicable).

Note: If your OpenClaw config uses plugins.allow, allowlist the plugin id lossless-claw plus any other active plugins you rely on. Do not add command tokens or aliases like lossless or /lcm to plugins.allow; that setting only accepts plugin ids. In some setups, narrowing the allowlist can prevent plugin-backed integrations from loading, even if lossless-claw itself is installed correctly. Restart the gateway after plugin config changes.

Configure OpenClaw

In most cases, no manual JSON edits are needed after openclaw plugins install.

If you need to set it manually, ensure the context engine slot points at lossless-claw:

{
  "plugins": {
    "slots": {
      "contextEngine": "lossless-claw"
    }
  }
}

Restart OpenClaw after configuration changes.

Configuration

LCM is configured through a combination of plugin config and environment variables. Environment variables take precedence for backward compatibility.

Plugin config

Add a lossless-claw entry under plugins.entries in your OpenClaw config:

{
  "plugins": {
    "entries": {
      "lossless-claw": {
        "enabled": true,
        "config": {
          "freshTailCount": 64,
          "leafChunkTokens": 80000,
          "newSessionRetainDepth": 2,
          "contextThreshold": 0.75,
          "incrementalMaxDepth": 1,
          "cacheAwareCompaction": {
            "enabled": true,
            "cacheTTLSeconds": 300
          },
          "ignoreSessionPatterns": [
            "agent:*:cron:**"
          ],
          "transcriptGcEnabled": false,
          "proactiveThresholdCompactionMode": "deferred",
          "summaryModel": "openai/gpt-5.4-mini",
          "expansionModel": "openai/gpt-5.4-mini",
          "delegationTimeoutMs": 300000,
          "summaryTimeoutMs": 60000
        }
      }
    }
  }
}

leafChunkTokens controls how many source tokens can accumulate in a leaf compaction chunk before summarization is triggered. The default is 20000, but quota-limited summary providers may benefit from a larger value to reduce compaction frequency. summaryModel and summaryProvider let you pin compaction summarization to a cheaper or faster model than your main OpenClaw session model. expansionModel does the same for lcm_expand_query sub-agent calls (drilling into summaries to recover detail). delegationTimeoutMs controls how long lcm_expand_query waits for that delegated sub-agent to finish before returning a timeout error; it defaults to 120000 (120s). summaryTimeoutMs controls the per-call timeout for model-backed LCM summarization; it defaults to 60000 (60s). When unset, the model settings still fall back to OpenClaw's configured default model/provider. See Expansion model override requirements for the required subagent trust policy when using expansionModel.

Environment variables

Variable	Default	Description
LCM_ENABLED	true	Enable/disable the plugin
LCM_DATABASE_PATH	~/.openclaw/lcm.db	Path to the SQLite database
LCM_IGNORE_SESSION_PATTERNS	""	Comma-separated glob patterns for session keys to exclude from LCM storage
LCM_STATELESS_SESSION_PATTERNS	""	Comma-separated glob patterns for session keys that may read from LCM but never write to it
LCM_SKIP_STATELESS_SESSIONS	true	Enable stateless-session write skipping for matching session keys
LCM_CONTEXT_THRESHOLD	0.75	Fraction of context window that triggers compaction (0.0–1.0)
LCM_FRESH_TAIL_COUNT	64	Number of recent messages protected from compaction
LCM_NEW_SESSION_RETAIN_DEPTH	2	Context retained after /new (-1 keeps all context, 2 keeps d2+)
LCM_LEAF_MIN_FANOUT	8	Minimum raw messages per leaf summary
LCM_CONDENSED_MIN_FANOUT	4	Minimum summaries per condensed node
LCM_CONDENSED_MIN_FANOUT_HARD	2	Relaxed fanout for forced compaction sweeps
LCM_INCREMENTAL_MAX_DEPTH	1	How deep incremental compaction goes (0 = leaf only, 1 = one condensed pass, -1 = unlimited)
LCM_LEAF_CHUNK_TOKENS	20000	Max source tokens per leaf compaction chunk
LCM_LEAF_TARGET_TOKENS	1200	Target token count for leaf summaries
LCM_CONDENSED_TARGET_TOKENS	2000	Target token count for condensed summaries
LCM_MAX_EXPAND_TOKENS	4000	Token cap for sub-agent expansion queries
LCM_LARGE_FILE_TOKEN_THRESHOLD	25000	File blocks above this size are intercepted and stored separately
LCM_LARGE_FILE_SUMMARY_PROVIDER	""	Provider override for large-file summarization
LCM_LARGE_FILE_SUMMARY_MODEL	""	Model override for large-file summarization
LCM_SUMMARY_MODEL	""	Model override for compaction summarization; falls back to OpenClaw's default model when unset
LCM_SUMMARY_PROVIDER	""	Provider override for compaction summarization; falls back to OPENCLAW_PROVIDER or the provider embedded in the model ref
LCM_SUMMARY_BASE_URL	(from OpenClaw / provider default)	Base URL override for summarization API calls
LCM_EXPANSION_MODEL	(from OpenClaw)	Model override for lcm_expand_query sub-agent (e.g. openai/gpt-5.4-mini)
LCM_EXPANSION_PROVIDER	(from OpenClaw)	Provider override for lcm_expand_query sub-agent
LCM_DELEGATION_TIMEOUT_MS	120000	Max time to wait for delegated lcm_expand_query sub-agent completion
LCM_SUMMARY_TIMEOUT_MS	60000	Max time to wait for a single model-backed LCM summarizer call
LCM_PRUNE_HEARTBEAT_OK	false	Retroactively delete HEARTBEAT_OK turn cycles from LCM storage
LCM_TRANSCRIPT_GC_ENABLED	false	Enable transcript rewrite GC during maintain()
LCM_PROACTIVE_THRESHOLD_COMPACTION_MODE	deferred	Choose whether proactive threshold compaction is deferred into maintenance debt or kept inline for legacy behavior
LCM_CACHE_TTL_SECONDS	300	Cache TTL used by cache-aware deferred compaction when provider/runtime telemetry does not supply a more specific retention window

Transcript GC rewrites are disabled by default. Set transcriptGcEnabled or LCM_TRANSCRIPT_GC_ENABLED to turn them on explicitly.
Deferred proactive compaction is also the default. Set proactiveThresholdCompactionMode or LCM_PROACTIVE_THRESHOLD_COMPACTION_MODE to inline only if you need legacy foreground compaction behavior. In deferred mode, lossless-claw records one coalesced prompt-mutating debt item after the turn, leaves background maintain() to process only non-prompt-mutating work while Anthropic cache is still hot, and then consumes that debt pre-assembly once the cache is cold or the prompt is approaching overflow.

Expansion model override requirements

If you want lcm_expand_query to run on a dedicated model via expansionModel or LCM_EXPANSION_MODEL, OpenClaw must explicitly trust the plugin to request sub-agent model overrides.

For most setups, openai/gpt-5.4-mini is a better starting point than Anthropic Haiku because it is cheap, fast, and does not depend on Anthropic quota remaining.

Add a subagent policy under plugins.entries.lossless-claw and allowlist the canonical provider/model target you want the plugin to use:

{
  "models": {
    "openai/gpt-4.1-mini": {}
  },
  "plugins": {
    "entries": {
      "lossless-claw": {
        "enabled": true,
        "subagent": {
          "allowModelOverride": true,
          "allowedModels": ["openai/gpt-4.1-mini"]
        },
        "config": {
          "expansionModel": "openai/gpt-4.1-mini"
        }
      }
    }
  }
}

• subagent.allowModelOverride is required for OpenClaw to honor plugin-requested per-run provider/model overrides.
• subagent.allowedModels is optional but recommended. Use "*" only if you intentionally want to trust any target model.
• The chosen expansion target must also be available in OpenClaw's normal model catalog. If it is not already configured elsewhere, add it under the top-level models map as shown above.
• If you prefer splitting provider and model, set config.expansionProvider and use a bare config.expansionModel.

Plugin config equivalents:

• ignoreSessionPatterns
• statelessSessionPatterns
• skipStatelessSessions
• transcriptGcEnabled
• newSessionRetainDepth
• summaryModel
• summaryProvider
• delegationTimeoutMs
• summaryTimeoutMs

Environment variables still win over plugin config when both are set.

Summary model priority

For compaction summarization, lossless-claw resolves the model in this order:

1. LCM_SUMMARY_MODEL / LCM_SUMMARY_PROVIDER
2. Plugin config summaryModel / summaryProvider
3. OpenClaw's default compaction model/provider
4. Legacy per-call model/provider hints

If summaryModel already includes a provider prefix such as anthropic/claude-sonnet-4-20250514, summaryProvider is ignored for that choice. Otherwise, the provider falls back to the matching override, then OPENCLAW_PROVIDER, then the provider inferred by the caller.

Runtime-managed OAuth providers are supported here too. In particular, openai-codex and github-copilot auth profiles can be used for summary and expansion calls without a separate API key.

Recommended starting configuration

LCM_FRESH_TAIL_COUNT=64
LCM_LEAF_CHUNK_TOKENS=20000
LCM_INCREMENTAL_MAX_DEPTH=1
LCM_CONTEXT_THRESHOLD=0.75
LCM_SUMMARY_MODEL=openai/gpt-5.4-mini
LCM_EXPANSION_MODEL=openai/gpt-5.4-mini

• freshTailCount=64 protects the last 64 messages from compaction, giving the model more recent context for continuity.
• leafChunkTokens=20000 limits how large each leaf compaction chunk can grow before LCM summarizes it. Increase this when your summary provider is quota-limited and frequent leaf compactions are exhausting that quota.
• incrementalMaxDepth=1 runs one condensed pass after each leaf compaction by default. Set to 0 for leaf-only behavior, a larger positive integer for a deeper cap, or -1 for unlimited cascading.
• contextThreshold=0.75 triggers compaction when context reaches 75% of the model's window, leaving headroom for the model's response.

Session exclusion patterns

Session reset semantics

Lossless-claw distinguishes OpenClaw's two session-reset commands:

• /new keeps the active conversation row and all stored summaries, but prunes context_items so the next turn rebuilds context from retained summaries instead of the fresh tail.
• /reset archives the active conversation row and creates a new active row for the same stable sessionKey, giving the next turn a clean LCM conversation while preserving prior history.

For large sessions, neither command is a perfect “keep my live agent context, but stop writing into this giant active LCM row” tool:

• /new keeps writing into the same active LCM conversation row.
• /reset changes OpenClaw session flow, which is heavier than users often want when their real problem is just LCM row size.

/lcm rotate fills that gap. It replaces one rolling rotate-latest SQLite backup, rewrites the current session transcript down to the preserved live tail plus current session settings, and refreshes the bootstrap frontier on the same active LCM conversation so dropped transcript history is not replayed. Existing summaries, context items, and conversation identity stay in place; only the transcript backing is compacted. If you want additional timestamped snapshots instead, run /lcm backup.

newSessionRetainDepth (or LCM_NEW_SESSION_RETAIN_DEPTH) controls how much summary structure survives /new:

• -1: keep all existing context items
• 0: keep all summaries, drop only fresh-tail messages
• 1: keep d1+ summaries
• 2: keep d2+ summaries; recommended default
• 3+: keep only deeper, more abstract summaries

Lossless-claw applies /new pruning through before_reset and uses session_end to catch transcript rollovers such as /reset, idle or daily session rotation, compaction session replacement, and deletions. User-facing confirmation text after /new or /reset must still be emitted by OpenClaw's command handlers.

Use ignoreSessionPatterns or LCM_IGNORE_SESSION_PATTERNS to keep low-value sessions completely out of LCM. Matching sessions do not create conversations, do not store messages, and do not participate in compaction or delegated expansion grants.

Pattern rules:

• * matches any characters except :
• ** matches anything, including :
• Patterns match the full session key

Examples:

• agent:*:cron:** excludes cron sessions for any agent, including isolated run sessions like agent:main:cron:daily-digest:run:run-123
• agent:main:subagent:** excludes all main-agent subagent sessions
• agent:ops:** excludes every session under the ops agent id

Environment variable example:

LCM_IGNORE_SESSION_PATTERNS=agent:*:cron:**,agent:main:subagent:**

Plugin config example:

{
  "plugins": {
    "entries": {
      "lossless-claw": {
        "config": {
          "ignoreSessionPatterns": [
            "agent:*:cron:**",
            "agent:main:subagent:**"
          ]
        }
      }
    }
  }
}

Stateless session patterns

Use statelessSessionPatterns or LCM_STATELESS_SESSION_PATTERNS for sessions that should still be able to read from existing LCM context, but should never create or mutate LCM state themselves. This is useful for delegated or temporary sub-agent sessions that should benefit from retained context without polluting the database.

When skipStatelessSessions or LCM_SKIP_STATELESS_SESSIONS is enabled, matching sessions:

• skip bootstrap imports
• skip message persistence during ingest and after-turn hooks
• skip compaction writes and delegated expansion grant writes
• can still assemble context from already-persisted conversations when a matching conversation exists

Pattern rules are the same as ignoreSessionPatterns, and matching is done against the full session key.

Environment variable example:

LCM_STATELESS_SESSION_PATTERNS=agent:*:subagent:**,agent:ops:subagent:**
LCM_SKIP_STATELESS_SESSIONS=true

Plugin config example:

{
  "plugins": {
    "entries": {
      "lossless-claw": {
        "config": {
          "statelessSessionPatterns": [
            "agent:*:subagent:**",
            "agent:ops:subagent:**"
          ],
          "skipStatelessSessions": true
        }
      }
    }
  }
}

OpenClaw session reset settings

LCM preserves history through compaction, but it does not change OpenClaw's core session reset policy. If sessions are resetting sooner than you want, increase OpenClaw's session.reset.idleMinutes or use a channel/type-specific override.

{
  "session": {
    "reset": {
      "mode": "idle",
      "idleMinutes": 10080
    }
  }
}

• session.reset.mode: "idle" keeps a session alive until the idle window expires.
• session.reset.idleMinutes is the actual reset interval in minutes.
• OpenClaw does not currently enforce a maximum idleMinutes; in source it is validated only as a positive integer.
• If you also use daily reset mode, idleMinutes acts as a secondary guard and the session resets when either the daily boundary or the idle window is reached first.
• Legacy session.idleMinutes still works, but OpenClaw prefers session.reset.idleMinutes.

Useful values:

• 1440 = 1 day
• 10080 = 7 days
• 43200 = 30 days
• 525600 = 365 days

For most long-lived LCM setups, a good starting point is:

{
  "session": {
    "reset": {
      "mode": "idle",
      "idleMinutes": 10080
    }
  }
}

Documentation

• Configuration guide
• Architecture
• Agent tools
• TUI Reference
• lcm-tui
• Optional: enable FTS5 for fast full-text search

Development

# Build (bundles TypeScript to dist/index.js)
pnpm build

# Run tests
npx vitest

# Type check
npx tsc --noEmit

# Run a specific test file
npx vitest test/engine.test.ts

Project structure

index.ts                    # Plugin entry point and registration
src/
  engine.ts                 # LcmContextEngine — implements ContextEngine interface
  assembler.ts              # Context assembly (summaries + messages → model context)
  compaction.ts             # CompactionEngine — leaf passes, condensation, sweeps
  summarize.ts              # Depth-aware prompt generation and LLM summarization
  retrieval.ts              # RetrievalEngine — grep, describe, expand operations
  expansion.ts              # DAG expansion logic for lcm_expand_query
  expansion-auth.ts         # Delegation grants for sub-agent expansion
  expansion-policy.ts       # Depth/token policy for expansion
  large-files.ts            # File interception, storage, and exploration summaries
  integrity.ts              # DAG integrity checks and repair utilities
  transcript-repair.ts      # Tool-use/result pairing sanitization
  types.ts                  # Core type definitions (dependency injection contracts)
  openclaw-bridge.ts        # Bridge utilities
  db/
    config.ts               # LcmConfig resolution from env vars
    connection.ts           # SQLite connection management
    migration.ts            # Schema migrations
  store/
    conversation-store.ts   # Message persistence and retrieval
    summary-store.ts        # Summary DAG persistence and context item management
    fts5-sanitize.ts        # FTS5 query sanitization
  tools/
    lcm-grep-tool.ts        # lcm_grep tool implementation
    lcm-describe-tool.ts    # lcm_describe tool implementation
    lcm-expand-tool.ts      # lcm_expand tool (sub-agent only)
    lcm-expand-query-tool.ts # lcm_expand_query tool (main agent wrapper)
    lcm-conversation-scope.ts # Conversation scoping utilities
    common.ts               # Shared tool utilities
test/                       # Vitest test suite
specs/                      # Design specifications
openclaw.plugin.json        # Plugin manifest with config schema and UI hints
tui/                        # Interactive terminal UI (Go)
  main.go                   # Entry point and bubbletea app
  data.go                   # Data loading and SQLite queries
  dissolve.go               # Summary dissolution
  repair.go                 # Corrupted summary repair
  rewrite.go                # Summary re-summarization
  transplant.go             # Cross-conversation DAG copy
  prompts/                  # Depth-aware prompt templates
.goreleaser.yml             # GoReleaser config for TUI binary releases

License

MIT