pi-memory

Persistent memory for pi. Learns corrections, preferences, and project patterns from sessions and injects them into future conversations.

Features

• Automatic learning — Extracts preferences, project patterns, and corrections from conversations at session end via LLM consolidation
• Context injection — Automatically adds relevant memory into every new session's system prompt
• Corrections stick — Mistakes you correct once become permanent lessons (e.g. "use sed for daily notes, not echo >>")
• Complements session-search — session-search finds what you did, pi-memory remembers what you learned

Install

Recommended: Install pi-total-recall to get the complete context stack — persistent memory, session history search, and local knowledge search in one package:

pi install pi-total-recall

Or install pi-memory standalone:

pi install npm:@samfp/pi-memory

Or add to ~/.pi/agent/settings.json:

{
  "packages": ["npm:@samfp/pi-memory"]
}

Note: Make sure you use the @samfp/ scope. There is an unrelated pi-memory package on npm that will install instead if you omit the scope.

Memory Types

Type	Key prefix	Example
Preferences	pref.*	pref.commit_style → "conventional commits"
Project patterns	project.*	project.rosie.di → "Dagger dependency injection"
Tool preferences	tool.*	tool.sed → "use for daily note insertion"
User identity	user.*	user.timezone → "US/Pacific"
Lessons	(table)	"DON'T: use echo >> for vault notes, use sed"

Tools

Tool	Description
memory_search	Search semantic memory by keyword
memory_remember	Manually store a fact or lesson
memory_forget	Delete a fact or lesson
memory_lessons	List learned corrections
memory_stats	Show memory statistics

Commands

Command	Description
/memory-consolidate	Manually trigger memory extraction from current session

How It Works

1. session_start — Opens the SQLite store, shows memory stats briefly in the status bar, and injects a <memory> context block as a hidden custom message (customType pi-memory-context, display: false) before any user message. One-shot per session.
2. agent_end — Collects conversation messages for later consolidation
3. session_shutdown — Runs LLM consolidation (via pi -p --print) to extract structured knowledge, then closes the store

Consolidation

At session end, if there were ≥3 user messages, the extension sends the conversation to an LLM and asks it to extract:

• Preferences — coding style, workflow habits, tool choices
• Project patterns — languages, frameworks, architecture decisions
• Corrections — things you corrected, mistakes to avoid

Only facts with confidence ≥ 0.8 are stored. Lessons are deduplicated using exact match and Jaccard similarity (≥ 0.7 threshold).

Injection

At session start, stored memory is organized into sections (preferences, project context scoped to cwd, tool preferences, lessons, user identity) and injected once as a hidden <memory> custom message that sits before the first user message in history. The block is capped at 8KB.

The injection happens at session_start via pi.sendMessage, not per-turn. This is deliberate:

• Correctness. A per-turn injection via before_agent_start places the memory block after the user's question in the message list, so the model ends up responding to the memory block instead of the user. One-shot at the top of history avoids that ordering trap.
• Cache stability. Mutating the system prompt per turn (as earlier versions did) invalidates the provider's prefix cache after the system block (Bedrock / Anthropic cache_control), forcing the conversation suffix to be re-written at cacheWrite rates on every turn boundary.
• Simplicity. One block, one time, cached for the whole session.

Tradeoff: per-user-message selective injection is off by default — the fallback dump covers preferences, project context for the cwd, tool preferences, lessons, and user identity, which is enough for typical workflows given the 8KB cap. Users with large memory stores who want per-query relevance can opt in (see "Per-turn injection" below).

Per-turn injection (opt-in)

Set perTurnInjection: true to restore v1.0.x per-turn behavior:

{
  "memory": {
    "perTurnInjection": true
  }
}

When enabled:

• The session_start fallback dump is skipped.
• Each user turn runs a semantic search against the current prompt, and the result is appended to the system prompt (not sent as a custom message — that would place it after the user's question in history).
• Pro: facts outside the 8KB fallback dump reach the model when they match the current prompt.
• Con: the system prompt mutates per turn, invalidating the provider's prefix cache after the system block (Bedrock / Anthropic cache_control). The conversation suffix gets re-cached at cacheWrite rates on every user-turn boundary (~12.5x cacheRead on Claude).

Correctness is preserved either way: systemPrompt is a separate field from the messages list, so the user's question remains the last user-role message.

Lesson filtering in per-turn mode — When perTurnInjection: true, the lessonInjection config takes effect:

{
  "memory": {
    "perTurnInjection": true,
    "lessonInjection": "selective"
  }
}

In selective lesson mode, lessons are filtered by:

1. Prompt relevance — FTS search against the user's first message
2. Project context — lessons matching the current working directory's project
3. Category inference — keywords in the prompt trigger relevant categories (e.g. "pentest" pulls in bug-bounty lessons, "blog post" pulls in writing lessons)
4. General lessons — always included regardless of prompt

The result is capped at 15 most relevant lessons instead of all of them.

lessonInjection	Behavior (only when perTurnInjection: true)
"all" (default)	All lessons injected every turn
"selective"	Only relevant lessons based on prompt, project, and category

Consolidation model — At session end, pi-memory spawns a lightweight pi -p --print process to extract facts and lessons from the conversation. By default it uses claude-sonnet-4-20250514, which is a no-op for users on non-Anthropic providers. Override it with any model string your pi binary accepts:

{
  "memory": {
    "lessonInjection": "selective",
    "consolidationModel": "openai/gpt-4.1-mini"
  }
}

Set this in ~/.pi/agent/settings.json for a user-wide default, or in {project}/.pi/settings.json (either under memory or pi-memory) to override per project. Examples: openai/gpt-4.1-mini, ollama/qwen3:8b, anthropic/claude-haiku-4-5-20251001. If the model string is invalid the consolidation sub-process fails silently and the session's memory is simply not consolidated — no data is lost from previous sessions.

Storage

SQLite database at ~/.pi/memory/memory.db (WAL mode). Three tables:

• semantic — key-value facts with confidence scores
• lessons — learned corrections with dedup
• events — audit log of all memory operations

Project-local storage

To keep a project's memory isolated from your user-global memory, add one of the following to {project}/.pi/settings.json:

{
  // Package-specific — wins over the cascade below.
  "pi-memory": {
    "localPath": ".pi/memory"   // resolves to {project}/.pi/memory/memory.db
  }
}

Or, if installed via pi-total-recall, a single cascade key covers all three bundled packages:

{
  "pi-total-recall": {
    "localPath": ".pi/total-recall"
    // pi-memory             → {project}/.pi/total-recall/memory/memory.db
    // pi-session-search     → {project}/.pi/total-recall/session-search/
    // pi-knowledge-search   → {project}/.pi/total-recall/knowledge-search/
  }
}

Resolution order (highest priority first):

1. pi-memory.localPath in {cwd}/.pi/settings.json
2. pi-total-recall.localPath cascade → {localPath}/memory/memory.db
3. Global default: ~/.pi/memory/memory.db

Existing global installs are unaffected — this is strictly additive.

License

MIT