pi-icarus-hook

Binds Pi to an existing Hermes/Icarus Memory OS.

Use this when you want Pi to get the same ambient memory behavior Hermes gets from Memory OS - Icarus: retrieve context before an answer, capture useful exchanges afterward, and expose normal Fabric tools.

Requires the Memory OS ecosystem to hook into.

At a glance

• Thin bridge: Pi lifecycle events -> Icarus hooks.
• Memory is automatic: context is injected before the model answers.
• Injected context is visible by default; hide it per-session with /icarus context hide.
• /icarus controls memory hooks, context visibility, defaults, and inspection.
• Pi footer shows 🪽 Icarus while ambient memory hooks are active.
• Normal Fabric tools are enabled by default: write, recall, search, pending, curate, brief, Obsidian init.
• Admin/training tools are implemented but hidden by default: export, train, eval, switch model, rollback, telemetry, report.
• Not included: raw Qdrant/Redis/worker controls, ingestion queues, reflection controls, or ground-truth editing.
• Persistent Python worker: required so Icarus keeps per-session state across hook calls.

Example experience

A Pi session starts. pi-icarus-hook calls Icarus, receives any relevant session or memory context, and injects it into Pi before the model answers.

User prompt
  -> Pi before_agent_start
    -> pi-icarus-hook
      -> Icarus pre_llm_call(...)
        -> Fabric / sessions / Memory OS context lookup
      <- { "context": "relevant memories..." }
  -> Pi model answers with that context available

After the answer, the extension calls Icarus again so useful exchanges can be captured and later persisted.

Default UI: injected context is visible, and the footer shows 🪽 Icarus while hooks are active.

Install

Install the package into Pi:

pi install npm:pi-icarus-hook

Usage

Start Pi normally:

pi

For a one-shot prompt:

pi -p "What is the last project we worked on?"

Commands

Command	Effect
/icarus	Toggle memory hooks for this session
/icarus on / /icarus off / /icarus status	Control memory hooks
/icarus context	Toggle injected context visibility for this session
/icarus context show / /icarus context hide / /icarus context status	Control context visibility now
/icarus context default show / /icarus context default hide / /icarus context default status	Control startup default for future sessions
/icarus context default hide project	Write .pi/settings.json
/icarus context default hide global	Write ${PI_CODING_AGENT_DIR:-~/.pi/agent}/settings.json
/icarus config	Print effective config
/icarus schema	Print settings schema

Runtime toggles are session-local. Default toggles write settings and apply on next Pi start. Use both if you want now + future:

/icarus context hide
/icarus context default hide

The read-only agent tool is icarus_hook_config.

To hide injected context by default in JSON instead:

{
  "piIcarusHook": {
    "contextDisplay": false
  }
}

Requirements

• Node.js 22 or newer.
• Python available as python3, or set ICARUS_PYTHON.
• A local Icarus checkout. By default this is expected at ~/.hermes/plugins/icarus.
• Any Memory OS, Qdrant, SQLite, or LLM dependencies required by the Icarus hooks you call.

Configuration

Most setups need little or no configuration if Hermes/Icarus uses the standard local layout.

Pi extension behavior is read in this order:

1. Project settings at .pi/settings.json.
2. Global Pi agent settings at ${PI_CODING_AGENT_DIR:-~/.pi/agent}/settings.json.
3. Built-in defaults.

Environment variables are only used for external Hermes/Icarus runtime paths and identity, not for Pi UI/tool/hook behavior.

Use piIcarusHook or pi-icarus-hook in Pi settings:

{
  "piIcarusHook": {
    "icarusDir": "~/.hermes/plugins/icarus",
    "hermesHome": "~/.hermes",
    "fabricDir": "~/fabric",
    "agent": "pi-agent",
    "platform": "pi",
    "hooks": true,
    "tools": true,
    "adminTools": false,
    "timeoutMs": 30000,
    "contextDisplay": true,
    "footerStatus": "🪽 Icarus"
  }
}

To customize the footer label globally, put this in ${PI_CODING_AGENT_DIR:-~/.pi/agent}/settings.json:

{
  "piIcarusHook": {
    "footerStatus": "🪽 Icarus"
  }
}

The Pi-specific keys platform, hooks, tools, adminTools, timeoutMs, contextDisplay, and footerStatus are intentionally Pi-settings-only. They are not read from environment variables because they control Pi adapter/UI/tool behavior, not the external Icarus/Hermes runtime.

Pi settings:

Setting	Default	Purpose
platform	pi	Platform label passed to Icarus hooks
hooks / bindHooks	true	Register lifecycle hooks
tools / registerTools	true	Register normal Fabric tools
adminTools / registerAdminTools	false	Register admin/training tools
timeoutMs / callTimeoutMs	30000	Timeout for each Icarus worker call
contextDisplay (hiddenDisplay legacy alias)	true	Show injected context instead of hiding it
footerStatus / statusLabel	🪽 Icarus	Footer text shown while ambient hooks are active

Typical variables:

Variable	Default	Purpose
ICARUS_DIR	~/.hermes/plugins/icarus	Local Icarus Python package directory
HERMES_HOME	~/.hermes when it exists	Hermes home for Icarus state files
HERMES_AGENT_NAME	inferred from .hermes-<agent>, else pi-agent	Agent name passed to Icarus
FABRIC_DIR	~/fabric	Shared Fabric markdown directory

Advanced variables:

Variable	Default	Purpose
ICARUS_PYTHON	python3	Python executable for the worker
STATE_DB_PATH / HERMES_STATE_DB	unset	Optional explicit Hermes session SQLite path
FABRIC_PROJECT_ID	current directory name	Project id passed to Icarus writes/retrieval

Boolean values accept false, 0, no, off, and disabled as false.

Inspection

For machine-readable inspection, the extension exports CONFIG_SCHEMA from src/config-schema.ts and exposes:

• /icarus config — effective config and settings snippet.
• /icarus schema — supported settings schema.
• icarus_hook_config — read-only agent tool with the same schema/effective config.

/icarus config, /icarus schema, and icarus_hook_config are read-only. /icarus context default ... is the explicit settings-writing path and reports the changed file.

What is included

pi-icarus-hook exposes the Icarus/Fabric surface that is safe and useful inside a normal Pi coding session.

Ambient memory hooks

These run automatically when Pi emits lifecycle events:

Pi event	Icarus hook	Behavior
session_start	icarus.hooks.on_session_start()	Injects startup context when returned
before_agent_start	icarus.hooks.pre_llm_call()	Injects per-turn memory context when returned
agent_end	icarus.hooks.post_llm_call()	Captures decisions and updates Icarus session state
session_shutdown	icarus.hooks.on_session_end()	Scores and persists the session, then closes the worker

The hook path is the recommended default. The model does not need to remember to call a tool before every answer; memory is injected as infrastructure. Use /icarus off to stop loading/saving memory for the current session, or /icarus context hide to keep hooks active but hide injected context.

Normal Fabric tools, enabled by default

These are regular work-session tools and are safe to expose to Pi agents by default:

• fabric_write — write a structured entry into shared Fabric memory.
• fabric_recall — ranked retrieval of relevant Fabric memories by query.
• fabric_search — literal keyword search across Fabric entries.
• fabric_pending — list open tasks, reviews, and tickets assigned through Fabric.
• fabric_curate — update an entry's training value: high, normal, or low.
• fabric_brief — summarize pending work, recent Fabric activity, other agents' work, and suggested next action.
• fabric_init_obsidian — initialize Fabric as an Obsidian-readable vault.
• icarus_hook_config — inspect this extension's config schema and effective config.

Admin and training Fabric tools, disabled by default

These tools can export training data, start model training, evaluate models, or switch/rollback the active model. They are implemented, but hidden from Pi unless explicitly enabled:

• fabric_report — report corpus health and trainable-memory statistics.
• fabric_telemetry — show recall/reuse telemetry.
• fabric_export — export Fabric entries as fine-tuning JSONL training pairs.
• fabric_train — start a Together AI fine-tuning job from Fabric data.
• fabric_train_status — check status of a Fabric/Together fine-tuning job.
• fabric_models — list fine-tuned models trained from Fabric.
• fabric_eval — evaluate a replacement model against Fabric-derived eval prompts.
• fabric_switch_model — switch the active agent model to an evaluated replacement.
• fabric_rollback_model — restore the previous model config from backup.

Keep these hidden from Pi by default. They are operational controls, not normal coding-session memory tools. Hermes can keep them available for the main controller/operator, while Pi agents should only receive them when you intentionally enter admin mode.

Enable them only when needed in .pi/settings.json or global Pi settings:

{
  "piIcarusHook": {
    "adminTools": true
  }
}

What is not included

This package is not:

• a Memory OS client;
• a Qdrant, SQLite, or Fabric reimplementation;
• a replacement for Icarus;
• an orchestrator for Hermes internals;
• a Memory OS admin console.

It also does not expose lower-level Memory OS infrastructure controls. If those are needed, they should live in a separate optional admin extension rather than in this thin hook bridge.

Examples of intentionally absent admin/diagnostic surfaces:

• raw Qdrant/vector search
• Redis queue inspection
• worker health controls
• ingestion/reflection enqueue and retry controls
• ground-truth promotion or editing
• last injected context inspection

Keeping this package narrow avoids tool-name conflicts, reduces accidental destructive operations, and preserves the boundary: Pi calls Icarus; Icarus owns Memory OS behavior.

How it works

Simple cascade:

Pi event
  -> pi-icarus-hook
    -> icarus.hooks.pre_llm_call(...)
      -> Icarus internally uses Fabric / Qdrant / SQLite / Memory OS pieces

Context-returning hooks are injected back into Pi as visible messages by default:

Icarus returns {"context": "..."}
  -> pi-icarus-hook wraps it as a Pi message
    -> Pi receives the memory context with display: true

The persistent Python worker is intentional. Icarus keeps per-session dedupe sets and state.exchanges in Python module globals, so hook calls must share one long-lived Python process.

If Memory OS changes behind Icarus, pi-icarus-hook should not need to change unless Icarus hook or tool signatures change.

Verify

Run the package tests:

npm test

The smoke tests verify that Fabric tools pass through to Icarus and that hook session state persists across calls in the Python worker.

Developer install

From a local checkout:

npm install
npm run build

Load this checkout directly:

pi --no-extensions -e ./src/index.ts

For a one-shot local smoke test without other installed extensions:

pi --no-extensions -e ./src/index.ts -p "What is the last project we worked on?"

The package declares its Pi extension entry and gallery image in package.json:

{
  "pi": {
    "extensions": ["./src/index.ts"],
    "image": "https://raw.githubusercontent.com/Ryu-CZ/pi-icarus-hook/main/media/banner.webp"
  }
}