# Hermes Agent

> Expert in building self-improving AI agents with tool use, multi-platform messaging, and a closed learning loop. Proficient in LLM orchestration, tool integration, session management, and agent autonomy.

- Skill: `fathah/hermes-agent` (Agent Skill)
- Install (CLI): `npx skillmds@latest add fathah/hermes-agent`
- Raw SKILL.md: https://api.skillmd.com/api/skills/fathah/hermes-agent/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: fathah (https://skillmd.com/u/fathah)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/fathah/hermes-agent

---


# Hermes Agent - Complete Project Guide (A-Z)

> **Purpose of this document:** A single, comprehensive reference that explains everything about the Hermes Agent project — its architecture, source code, features, release history, and design patterns — so that any AI or developer can fully understand the system.

---

## Table of Contents

1. [Project Overview](#1-project-overview)
2. [Key Features Summary](#2-key-features-summary)
3. [Installation & Getting Started](#3-installation--getting-started)
4. [Project Structure](#4-project-structure)
5. [Core Architecture](#5-core-architecture)
   - 5.1 [AIAgent Class (run_agent.py)](#51-aiagent-class-run_agentpy)
   - 5.2 [Tool Orchestration (model_tools.py)](#52-tool-orchestration-model_toolspy)
   - 5.3 [Toolset System (toolsets.py)](#53-toolset-system-toolsetspy)
   - 5.4 [Tool Registry (tools/registry.py)](#54-tool-registry-toolsregistrypy)
   - 5.5 [Session Database (hermes_state.py)](#55-session-database-hermes_statepy)
   - 5.6 [Constants & Home Directory (hermes_constants.py)](#56-constants--home-directory-hermes_constantspy)
6. [CLI System](#6-cli-system)
   - 6.1 [Interactive CLI (cli.py)](#61-interactive-cli-clipy)
   - 6.2 [CLI Entry Point (hermes_cli/main.py)](#62-cli-entry-point-hermes_climainpy)
   - 6.3 [Configuration System (hermes_cli/config.py)](#63-configuration-system-hermes_cliconfigpy)
   - 6.4 [Slash Command Registry (hermes_cli/commands.py)](#64-slash-command-registry-hermes_clicommandspy)
   - 6.5 [Setup Wizard (hermes_cli/setup.py)](#65-setup-wizard-hermes_clisetupy)
   - 6.6 [Model Catalog (hermes_cli/models.py)](#66-model-catalog-hermes_climodelspy)
   - 6.7 [Skin/Theme Engine (hermes_cli/skin_engine.py)](#67-skintheme-engine-hermes_cliskin_enginepy)
7. [Tool System](#7-tool-system)
   - 7.1 [Terminal Tool (tools/terminal_tool.py)](#71-terminal-tool-toolsterminal_toolpy)
   - 7.2 [File Tools (tools/file_tools.py)](#72-file-tools-toolsfile_toolspy)
   - 7.3 [Web Tools (tools/web_tools.py)](#73-web-tools-toolsweb_toolspy)
   - 7.4 [Browser Tool (tools/browser_tool.py)](#74-browser-tool-toolsbrowser_toolpy)
   - 7.5 [Delegate Tool (tools/delegate_tool.py)](#75-delegate-tool-toolsdelegate_toolpy)
   - 7.6 [MCP Tool (tools/mcp_tool.py)](#76-mcp-tool-toolsmcp_toolpy)
   - 7.7 [Approval System (tools/approval.py)](#77-approval-system-toolsapprovalpy)
   - 7.8 [Terminal Backends (tools/environments/)](#78-terminal-backends-toolsenvironments)
8. [Agent Internals](#8-agent-internals)
   - 8.1 [Prompt Builder (agent/prompt_builder.py)](#81-prompt-builder-agentprompt_builderpy)
   - 8.2 [Context Compressor (agent/context_compressor.py)](#82-context-compressor-agentcontext_compressorpy)
   - 8.3 [Prompt Caching (agent/prompt_caching.py)](#83-prompt-caching-agentprompt_cachingpy)
   - 8.4 [Auxiliary Client (agent/auxiliary_client.py)](#84-auxiliary-client-agentauxiliary_clientpy)
   - 8.5 [Display & Spinner (agent/display.py)](#85-display--spinner-agentdisplaypy)
   - 8.6 [Skill Commands (agent/skill_commands.py)](#86-skill-commands-agentskill_commandspy)
9. [Messaging Gateway](#9-messaging-gateway)
   - 9.1 [GatewayRunner (gateway/run.py)](#91-gatewayrunner-gatewayrunpy)
   - 9.2 [Session Store (gateway/session.py)](#92-session-store-gatewaysessionpy)
   - 9.3 [Platform Adapters (gateway/platforms/)](#93-platform-adapters-gatewayplatforms)
10. [Cron Scheduling](#10-cron-scheduling)
11. [Skills System](#11-skills-system)
12. [Plugin System](#12-plugin-system)
13. [Memory System](#13-memory-system)
14. [ACP Server (IDE Integration)](#14-acp-server-ide-integration)
15. [API Server](#15-api-server)
16. [MCP Server Mode](#16-mcp-server-mode)
17. [RL Training Environments](#17-rl-training-environments)
18. [Profiles (Multi-Instance)](#18-profiles-multi-instance)
19. [Security Model](#19-security-model)
20. [Provider & Model System](#20-provider--model-system)
21. [Streaming & Reasoning](#21-streaming--reasoning)
22. [Release History](#22-release-history)
23. [File Dependency Chain](#23-file-dependency-chain)
24. [Key Design Patterns](#24-key-design-patterns)
25. [Configuration Reference](#25-configuration-reference)
26. [Known Pitfalls](#26-known-pitfalls)

---

## 1. Project Overview

**Hermes Agent** is a self-improving AI agent built by [Nous Research](https://nousresearch.com). It is an open-source (MIT licensed), Python-based project that provides:

- A **full interactive terminal UI** (CLI) for conversing with LLMs
- A **messaging gateway** supporting 16+ platforms (Telegram, Discord, Slack, WhatsApp, Signal, Matrix, Email, etc.)
- A **closed learning loop** — the agent creates skills from experience, improves them during use, nudges itself to persist knowledge, searches past conversations, and builds a deepening model of who you are
- **40+ built-in tools** — terminal execution, file manipulation, web search, browser automation, code execution, image generation, TTS/STT, and more
- **Any LLM provider** — OpenRouter (200+ models), Nous Portal (400+ models), OpenAI, Anthropic, Hugging Face, GitHub Copilot, z.ai/GLM, Kimi/Moonshot, MiniMax, Alibaba/DashScope, custom endpoints
- **Six terminal backends** — local, Docker, SSH, Modal (serverless), Daytona (serverless), Singularity (HPC)
- **Scheduled automations** via built-in cron scheduler
- **IDE integration** via ACP (Agent Communication Protocol) for VS Code, Zed, JetBrains
- **MCP integration** — both client (connect to any MCP server) and server (expose Hermes to MCP clients)
- **RL training** via Atropos environments for training the next generation of tool-calling models

**Tech Stack:**

- Python 3.11+ (core agent, tools, gateway, cron)
- Node.js (browser automation via agent-browser)
- SQLite with WAL mode and FTS5 (session storage, full-text search)
- OpenAI-compatible API (primary inference interface)
- Anthropic SDK (native Anthropic support)
- Rich + prompt_toolkit (CLI rendering)

**Repository:** `github.com/NousResearch/hermes-agent`
**Version:** 0.7.0 (as of April 2026)
**License:** MIT

---

## 2. Key Features Summary

| Feature                      | Description                                                                                                                                                                      |
| ---------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Terminal UI**              | Full TUI with multiline editing, slash-command autocomplete, conversation history, interrupt-and-redirect, streaming tool output                                                 |
| **Multi-Platform Messaging** | Telegram, Discord, Slack, WhatsApp, Signal, Matrix, Email, Home Assistant, DingTalk, Feishu/Lark, WeCom, Mattermost, SMS, Webhook — all from a single gateway process            |
| **Learning Loop**            | Agent-curated memory with periodic nudges, autonomous skill creation, skills self-improve during use, FTS5 session search with LLM summarization, Honcho dialectic user modeling |
| **Scheduled Tasks**          | Built-in cron scheduler with delivery to any platform (daily reports, nightly backups, weekly audits)                                                                            |
| **Subagent Delegation**      | Spawn isolated subagents for parallel workstreams with restricted toolsets                                                                                                       |
| **Execute Code**             | Python scripts that call tools via RPC, collapsing multi-step pipelines into zero-context-cost turns                                                                             |
| **Terminal Backends**        | Local, Docker, SSH, Modal, Daytona, Singularity — run on a $5 VPS or a GPU cluster                                                                                               |
| **Skills**                   | 70+ bundled skills across 28 categories, Skills Hub for community discovery, agentskills.io compatibility                                                                        |
| **Plugins**                  | Drop-in Python plugins with lifecycle hooks (pre_llm_call, post_llm_call, on_session_start, on_session_end)                                                                      |
| **MCP**                      | Client (connect to MCP servers for extended tools) and Server (expose conversations to MCP clients)                                                                              |
| **IDE Integration**          | VS Code, Zed, JetBrains via ACP server with session management and tool streaming                                                                                                |
| **API Server**               | OpenAI-compatible `/v1/chat/completions` endpoint for headless integrations                                                                                                      |
| **Profiles**                 | Multi-instance support — each profile gets isolated config, memory, sessions, skills, gateway                                                                                    |
| **Security**                 | Command approval system, secret redaction, SSRF protection, PII redaction, injection detection, credential directory protection                                                  |
| **RL Training**              | Atropos environments for batch trajectory generation and agent policy optimization                                                                                               |

---

## 3. Installation & Getting Started

```bash
# One-line install (Linux, macOS, WSL2)
curl -fsSL https://raw.githubusercontent.com/NousResearch/hermes-agent/main/scripts/install.sh | bash

# After install
source ~/.bashrc    # or: source ~/.zshrc
hermes              # start chatting

# Key commands
hermes model        # Choose LLM provider and model
hermes tools        # Configure which tools are enabled
hermes config set   # Set individual config values
hermes gateway      # Start the messaging gateway
hermes setup        # Run the full setup wizard
hermes update       # Update to latest version
hermes doctor       # Diagnose any issues
```

**For development:**

```bash
git clone https://github.com/NousResearch/hermes-agent.git
cd hermes-agent
curl -LsSf https://astral.sh/uv/install.sh | sh
uv venv venv --python 3.11
source venv/bin/activate
uv pip install -e ".[all,dev]"
python -m pytest tests/ -q    # ~3000 tests
```

---

## 4. Project Structure

```
hermes-agent/
├── run_agent.py              # AIAgent class — core conversation loop
├── model_tools.py            # Tool orchestration, _discover_tools(), handle_function_call()
├── toolsets.py               # Toolset definitions, _HERMES_CORE_TOOLS list
├── toolset_distributions.py  # Toolset sampling distributions for RL
├── cli.py                    # HermesCLI class — interactive CLI orchestrator
├── hermes_state.py           # SessionDB — SQLite session store (FTS5 search)
├── hermes_constants.py       # Shared constants, get_hermes_home()
├── hermes_time.py            # Timezone handling
├── utils.py                  # Shared utility functions
├── batch_runner.py           # Parallel batch processing
├── trajectory_compressor.py  # Trajectory compression for RL training
├── mcp_serve.py              # MCP server mode entry point
├── mini_swe_runner.py        # Minimal SWE benchmark runner
├── rl_cli.py                 # RL CLI commands
│
├── agent/                    # Agent internals
│   ├── prompt_builder.py         # System prompt assembly
│   ├── context_compressor.py     # Auto context compression
│   ├── prompt_caching.py         # Anthropic prompt caching
│   ├── auxiliary_client.py       # Auxiliary LLM client (vision, summarization)
│   ├── model_metadata.py         # Model context lengths, token estimation
│   ├── models_dev.py             # models.dev registry integration
│   ├── display.py                # KawaiiSpinner, tool preview formatting
│   ├── skill_commands.py         # Skill slash commands (shared CLI/gateway)
│   └── trajectory.py             # Trajectory saving helpers
│
├── hermes_cli/               # CLI subcommands and setup
│   ├── main.py               # Entry point — all `hermes` subcommands
│   ├── config.py             # DEFAULT_CONFIG, OPTIONAL_ENV_VARS, migration
│   ├── commands.py           # Slash command definitions + SlashCommandCompleter
│   ├── callbacks.py          # Terminal callbacks (clarify, sudo, approval)
│   ├── setup.py              # Interactive setup wizard
│   ├── skin_engine.py        # Skin/theme engine
│   ├── skills_config.py      # `hermes skills` — skill management
│   ├── tools_config.py       # `hermes tools` — tool management
│   ├── skills_hub.py         # Skills Hub integration
│   ├── models.py             # Model catalog, provider model lists
│   ├── model_switch.py       # Shared /model switch pipeline
│   └── auth.py               # Provider credential resolution
│
├── tools/                    # Tool implementations (one file per tool)
│   ├── registry.py           # Central tool registry
│   ├── approval.py           # Dangerous command detection
│   ├── terminal_tool.py      # Terminal/shell execution
│   ├── process_registry.py   # Background process management
│   ├── file_tools.py         # File read/write/search/patch
│   ├── web_tools.py          # Web search/extract
│   ├── browser_tool.py       # Browser automation
│   ├── code_execution_tool.py # execute_code sandbox
│   ├── delegate_tool.py      # Subagent delegation
│   ├── mcp_tool.py           # MCP client integration
│   ├── skills_tool.py        # Skill management tool
│   ├── todo_tool.py          # Todo/task tracking tool
│   ├── memory_tool.py        # Memory read/write tool
│   ├── tts_tool.py           # Text-to-speech
│   ├── vision_tool.py        # Image analysis
│   ├── image_gen_tool.py     # Image generation
│   └── environments/         # Terminal backends
│       ├── base.py               # BaseEnvironment ABC
│       ├── local.py              # Local execution
│       ├── docker.py             # Docker containers
│       ├── ssh.py                # SSH remote execution
│       ├── modal.py              # Modal serverless
│       ├── managed_modal.py      # Nous-hosted Modal
│       ├── daytona.py            # Daytona serverless
│       ├── singularity.py        # Singularity HPC containers
│       └── persistent_shell.py   # Persistent shell mixin
│
├── gateway/                  # Messaging platform gateway
│   ├── run.py                # GatewayRunner — main message loop
│   ├── session.py            # SessionStore — conversation persistence
│   ├── status.py             # Gateway status, token locks
│   └── platforms/            # 16 platform adapters
│       ├── base.py               # BasePlatformAdapter ABC
│       ├── telegram.py           # Telegram (polling + webhook)
│       ├── discord.py            # Discord
│       ├── slack.py              # Slack
│       ├── whatsapp.py           # WhatsApp
│       ├── matrix.py             # Matrix (E2EE)
│       ├── signal.py             # Signal
│       ├── email.py              # Email (IMAP/SMTP)
│       ├── homeassistant.py      # Home Assistant
│       ├── sms.py                # SMS (Twilio)
│       ├── mattermost.py         # Mattermost
│       ├── dingtalk.py           # DingTalk
│       ├── feishu.py             # Feishu/Lark
│       ├── wecom.py              # WeCom (Enterprise WeChat)
│       ├── webhook.py            # Generic webhook
│       └── api_server.py         # OpenAI-compatible API server
│
├── acp_adapter/              # ACP server (IDE integration)
│   ├── server.py             # HermesACPAgent class
│   ├── session.py            # SessionManager
│   ├── events.py             # Streaming callbacks
│   ├── permissions.py        # Approval callbacks
│   └── entry.py              # Entry point
│
├── cron/                     # Scheduler
│   ├── scheduler.py          # tick() — job execution engine
│   └── jobs.py               # Job storage and CRUD
│
├── plugins/                  # Plugin system
│   └── memory/               # 8 memory provider plugins
│       ├── openviking/
│       ├── mem0/
│       ├── hindsight/
│       ├── holographic/
│       ├── honcho/
│       ├── retaindb/
│       └── byterover/
│
├── environments/             # RL training environments (Atropos)
│   ├── hermes_base_env.py    # Abstract base RL environment
│   ├── agent_loop.py         # HermesAgentLoop — rollout execution
│   ├── tool_context.py       # ToolContext — sandbox for RL
│   ├── web_research_env.py   # Web research tasks
│   └── agentic_opd_env.py    # Observation-Prediction-Demo env
│
├── skills/                   # 70+ bundled skills across 28 categories
├── optional-skills/          # Additional optional skills
├── tests/                    # ~3000 pytest tests
├── scripts/                  # Install, update, packaging scripts
├── docker/                   # Docker build files
├── docs/                     # Documentation source (Docusaurus)
├── website/                  # Landing page
├── desktop/                  # Desktop app (Electron, separate repo)
├── tinker-atropos/           # RL submodule
│
├── pyproject.toml            # Python package config
├── AGENTS.md                 # Developer guide for AI assistants
├── RELEASE_v0.2.0.md → v0.7.0.md  # Release notes
└── cli-config.yaml.example   # Example config
```

**User config directory:** `~/.hermes/`

```
~/.hermes/
├── config.yaml           # User settings
├── .env                  # API keys and secrets
├── MEMORY.md             # Persistent agent memory
├── USER.md               # User profile
├── SOUL.md               # Agent personality/identity
├── sessions.db           # SQLite session database
├── skills/               # User-installed skills
├── skins/                # Custom CLI themes
├── plugins/              # User plugins
├── cron/                 # Cron jobs and output
│   ├── jobs.json
│   └── output/
├── cache/                # Image/audio cache
├── plans/                # Generated plans
├── profiles/             # Multi-instance profiles
└── mcp/                  # MCP server configs
```

---

## 5. Core Architecture

### 5.1 AIAgent Class (run_agent.py)

The `AIAgent` class is the heart of the system — the core conversation loop that orchestrates LLM calls, tool execution, context management, and response delivery.

**Constructor (~60 parameters):**

```python
class AIAgent:
    def __init__(self,
        model: str = "anthropic/claude-opus-4.6",
        max_iterations: int = 90,
        enabled_toolsets: list = None,
        disabled_toolsets: list = None,
        quiet_mode: bool = False,
        save_trajectories: bool = False,
        platform: str = None,            # "cli", "telegram", etc.
        session_id: str = None,
        session_db: SessionDB = None,
        skip_context_files: bool = False,
        skip_memory: bool = False,
        base_url: str = None,
        api_key: str = None,
        provider: str = None,
        api_mode: str = "chat_completions",  # or "anthropic_messages" or "codex_responses"
        tool_progress_callback = None,
        stream_delta_callback = None,
        thinking_callback = None,
        status_callback = None,
        iteration_budget: IterationBudget = None,
        credential_pool = None,
        checkpoints_enabled: bool = False,
        # ... plus provider, routing, callback params
    )
```

**Main Methods:**

| Method                                                                          | Returns  | Purpose                                                                            |
| ------------------------------------------------------------------------------- | -------- | ---------------------------------------------------------------------------------- |
| `chat(message, stream_callback)`                                                | `str`    | Simple interface — returns final response text                                     |
| `run_conversation(user_message, system_message, conversation_history, task_id)` | `dict`   | Full interface — returns `{final_response, messages, completed, api_calls, error}` |
| `_interruptible_api_call(api_kwargs)`                                           | Response | Runs API request in background thread with interrupt support                       |
| `_interruptible_streaming_api_call(api_kwargs, on_first_delta)`                 | Response | Streaming variant with delta callbacks                                             |

**The Core Agent Loop** (inside `run_conversation()`):

```python
while api_call_count < self.max_iterations and self.iteration_budget.remaining > 0:
    response = client.chat.completions.create(
        model=model, messages=messages, tools=tool_schemas
    )
    if response.tool_calls:
        for tool_call in response.tool_calls:
            result = handle_function_call(tool_call.name, tool_call.args, task_id)
            messages.append(tool_result_message(result))
        api_call_count += 1
    else:
        return response.content  # Final text response
```

**Key Behaviors:**

- **Three API modes:** `chat_completions` (OpenAI-compatible), `anthropic_messages` (Anthropic SDK), `codex_responses` (OpenAI Codex)
- **Parallel tool execution:** Independent tool calls run concurrently via ThreadPoolExecutor (unless they share file paths or are in the never-parallel list)
- **Interrupt support:** Background threads allow interrupt detection without blocking on HTTP
- **Error recovery:** Automatic fallback chain (primary → fallback model), retry with exponential backoff, context compression on token overflow
- **Budget pressure:** Warnings at 70% (caution) and 90% (urgent) of iteration budget
- **Oversized results:** Tool results >100K chars are saved to temp files with a preview
- **Stale connection detection:** 90s timeout for streaming, 60s read timeout

**IterationBudget** (thread-safe):

```python
class IterationBudget:
    def consume() -> bool    # Check and consume one iteration
    def refund()             # Give back iteration (for execute_code turns)
    @property remaining      # Remaining iterations
```

---

### 5.2 Tool Orchestration (model_tools.py)

Bridges the agent and tool registry — handles discovery, schema generation, and dispatch.

**Key Functions:**

| Function                                                                                | Purpose                                                                   |
| --------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- |
| `_discover_tools()`                                                                     | Imports all tool modules (each calls `registry.register()` on import)     |
| `get_tool_definitions(enabled_toolsets, disabled_toolsets, quiet_mode)`                 | Returns OpenAI-format tool schemas filtered by toolset                    |
| `handle_function_call(function_name, function_args, task_id, user_task, enabled_tools)` | Main dispatcher — routes calls to registry with arg coercion              |
| `coerce_tool_args(tool_name, args)`                                                     | Type coercion for LLM-generated arguments (string→int, string→bool, etc.) |

**Tool Discovery Order:**

1. Static tools (web_tools, terminal_tool, file_tools, browser_tool, etc.)
2. Optional tools (fal_client for image gen, honcho, etc.) — graceful fallback if missing
3. Plugin-registered tools
4. MCP server tools (dynamic, via tools/list_changed notifications)

**Special Tool Handling:**

- **Agent-level tools** (todo, memory, session_search, delegate_task): Intercepted by `run_agent.py` before `handle_function_call()`
- **execute_code**: Passes `enabled_tools` for sandbox tool list
- **Dynamic schema adjustments**: `browser_navigate` strips web_search reference if tools unavailable

**Async Bridging:**

- Persistent event loops (not `asyncio.run()`) to prevent "Event loop is closed" errors
- Main thread uses shared loop; worker threads get per-thread loops
- `_run_async()` detects running loop and spins up disposable thread if needed

---

### 5.3 Toolset System (toolsets.py)

Provides flexible tool grouping and composition.

**Core Toolsets:**

| Toolset          | Tools Included                                                                                   |
| ---------------- | ------------------------------------------------------------------------------------------------ |
| `web`            | web_search, web_extract, web_crawl                                                               |
| `terminal`       | terminal                                                                                         |
| `file`           | read_file, write_file, edit_file, list_files, search_files                                       |
| `browser`        | browser_navigate, browser_snapshot, browser_click, browser_type, browser_scroll, browser_extract |
| `vision`         | analyze_image                                                                                    |
| `image_gen`      | generate_image                                                                                   |
| `tts`            | text_to_speech                                                                                   |
| `todo`           | todo_read, todo_write                                                                            |
| `memory`         | memory_read, memory_write                                                                        |
| `session_search` | session_search                                                                                   |
| `delegation`     | delegate_task                                                                                    |
| `code_execution` | execute_code                                                                                     |
| `cronjob`        | create_job, list_jobs, delete_job                                                                |
| `messaging`      | send_message                                                                                     |
| `homeassistant`  | ha_get_states, ha_call_service, ...                                                              |

**Composite Toolsets:**

- `hermes-cli` — All core tools for CLI platform
- `hermes-telegram`, `hermes-discord`, etc. — Platform-specific tool sets
- `hermes-gateway` — Union of all platform tools
- `debugging` — terminal + file + web
- `safe` — Everything except terminal

**Resolution:**

```python
resolve_toolset(name, visited=None) → List[str]
# Recursively resolves toolset to tool names
# Handles composition (includes) and cycle detection
# Special aliases: "all" or "*" = all tools
```

---

### 5.4 Tool Registry (tools/registry.py)

Singleton managing all tool schemas and handlers. Circular-import safe — has no tool dependencies.

**ToolEntry** (per-tool metadata):

```python
@dataclass(slots=True)
class ToolEntry:
    name: str
    toolset: str
    schema: dict           # OpenAI-format tool definition
    handler: Callable      # Sync or async handler function
    check_fn: Callable     # Returns True if tool is available
    requires_env: list     # Required environment variables
    is_async: bool
    description: str
    emoji: str
```

**Key Methods:**

```python
registry.register(name, toolset, schema, handler, check_fn, requires_env)
registry.get_definitions(tool_names, quiet)  # Returns filtered schemas
registry.dispatch(name, args, **kwargs)      # Execute with async bridging
registry.deregister(name)                    # Remove (for MCP tool refresh)
registry.check_tool_availability()           # Returns (available, unavailable)
```

---

### 5.5 Session Database (hermes_state.py)

SQLite-based persistent session storage with FTS5 full-text search.

**Schema (v6):**

```sql
-- Sessions table
sessions (
    id TEXT PRIMARY KEY,
    source TEXT, user_id TEXT, model TEXT, model_config TEXT,
    system_prompt TEXT, parent_session_id TEXT,
    started_at TEXT, ended_at TEXT, end_reason TEXT,
    message_count INTEGER, tool_call_count INTEGER,
    input_tokens INTEGER, output_tokens INTEGER,
    cache_read_tokens INTEGER, cache_write_tokens INTEGER, reasoning_tokens INTEGER,
    estimated_cost_usd REAL, actual_cost_usd REAL,
    title TEXT  -- UNIQUE INDEX
)

-- Messages table
messages (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    session_id TEXT, role TEXT, content TEXT,
    tool_call_id TEXT, tool_calls TEXT,  -- JSON
    tool_name TEXT, timestamp TEXT,
    token_count INTEGER, finish_reason TEXT,
    reasoning TEXT, reasoning_details TEXT, codex_reasoning_items TEXT
)

-- FTS5 virtual table (auto-synced via triggers)
messages_fts (content)
```

**Concurrency Model:**

- WAL (Write-Ahead Logging) for concurrent readers + single writer
- `BEGIN IMMEDIATE` for write transactions (lock at start, not commit)
- Jitter retry on lock: 20-150ms random backoff, max 15 retries
- Periodic WAL checkpoint every 50 writes

**Key Operations:**

- `create_session()`, `end_session()`, `reopen_session()`
- `add_message()`, `get_messages()`
- `search_sessions(query)` — FTS5 full-text search
- `update_token_counts()` — Supports both incremental (CLI) and absolute (gateway) modes

---

### 5.6 Constants & Home Directory (hermes_constants.py)

Import-safe constants module with no circular dependencies.

```python
get_hermes_home() → Path          # HERMES_HOME env var or ~/.hermes
display_hermes_home() → str       # User-friendly display: "~/.hermes"
get_optional_skills_dir() → Path  # HERMES_OPTIONAL_SKILLS env var
parse_reasoning_effort(str) → Dict  # "high" → {"enabled": True, "effort": "high"}

# Key constants
OPENROUTER_BASE_URL = "https://openrouter.ai/api/v1"
NOUS_API_BASE_URL = "https://inference-api.nousresearch.com/v1"
AI_GATEWAY_BASE_URL = "https://ai-gateway.vercel.sh/v1"
VALID_REASONING_EFFORTS = ("xhigh", "high", "medium", "low", "minimal")
```

---

## 6. CLI System

### 6.1 Interactive CLI (cli.py)

The `HermesCLI` class provides the interactive terminal interface.

**Features:**

- **Rich** for banner/panels, **prompt_toolkit** for input with autocomplete
- **KawaiiSpinner** — animated faces during API calls, `┊` activity feed for tool results
- Multiline editing with Shift+Enter
- Slash-command autocomplete
- Session history with up/down arrow navigation
- Clipboard image paste (Alt+V / Ctrl+V)
- Status bar showing model, provider, and token counts
- Inline diff previews for file write/patch operations

**Configuration Loading:**

```python
load_cli_config() → dict
# Loads from ~/.hermes/config.yaml (or ./cli-config.yaml fallback)
# Merges with hardcoded defaults
# Expands ${ENV_VAR} references
# Maps terminal config → env vars
```

---

### 6.2 CLI Entry Point (hermes_cli/main.py)

All `hermes` subcommands are dispatched from here:

```
hermes                    # Default: interactive chat
hermes chat               # Explicit interactive mode
hermes gateway start|stop|status|install|uninstall
hermes setup              # Setup wizard
hermes model              # Select model/provider
hermes tools              # Configure tools
hermes skills             # Manage skills
hermes config set|get     # Direct config manipulation
hermes cron list|delete   # Cron job management
hermes doctor             # Diagnose issues
hermes sessions browse    # Session picker
hermes profile create|list|switch|delete|export|import
hermes mcp serve|add|remove  # MCP management
hermes acp                # Start ACP server
hermes update|uninstall|version
```

**Profile System:**

- `_apply_profile_override()` runs BEFORE any imports to set `HERMES_HOME`
- Pre-parses `--profile/-p` from argv
- Allows fully isolated agent instances with separate config, memory, sessions, skills

---

### 6.3 Configuration System (hermes_cli/config.py)

**Key Configuration Sections:**

```yaml
model: "anthropic/claude-opus-4.6" # or dict with provider/base_url/api_key
providers: {} # Provider-specific configs
fallback_providers: [] # Ordered failover list
credential_pool: {} # Multiple API keys per provider

agent:
  max_turns: 90
  gateway_timeout: 1800
  tool_use_enforcement: "auto"

terminal:
  backend: "local" # local|docker|modal|daytona|ssh|singularity
  timeout: 180
  persistent_shell: true
  docker_image: "nikolaik/python-nodejs:..."

compression:
  enabled: true
  threshold: 0.50 # Compress when 50% of context used
  target_ratio: 0.20 # Summary = 20% of compressed content
  protect_last_n: 20

auxiliary:
  vision: { provider, model }
  web_extract: { provider, model }
  compression: { provider, model }

memory:
  memory_enabled: true
  provider: "" # "" | "honcho" | "mem0" | etc.
  memory_char_limit: 2200

display:
  personality: "kawaii"
  show_reasoning: false
  inline_diffs: true
  skin: "default"
  streaming: true

tts:
  provider: "edge" # edge|elevenlabs|openai|neutts

stt:
  enabled: true
  provider: "local" # local|groq|openai

privacy:
  redact_pii: false

mcp_servers: {} # MCP server configurations

skills:
  external_dirs: [] # Additional skill directories

approvals:
  mode: "smart" # smart|always|off
```

**Config Files:**

- `~/.hermes/config.yaml` — User settings (authoritative)
- `~/.hermes/.env` — API keys and secrets
- Config version migration system (currently v5)

---

### 6.4 Slash Command Registry (hermes_cli/commands.py)

All slash commands defined centrally in `COMMAND_REGISTRY`:

```python
CommandDef(name, description, category, aliases, args_hint, cli_only, gateway_only)
```

**Derived automatically by:**

- CLI `process_command()` — dispatch on canonical name
- Gateway dispatch + help
- Telegram BotCommand menu
- Slack `/hermes` subcommands
- Autocomplete + help text

**Key Commands:**

| Command        | Aliases    | Description                   |
| -------------- | ---------- | ----------------------------- |
| `/new`         | `/reset`   | Start fresh conversation      |
| `/model`       |            | Show/switch model             |
| `/personality` |            | Set agent personality         |
| `/retry`       |            | Retry last turn               |
| `/undo`        |            | Remove last turn              |
| `/compress`    | `/compact` | Compress context              |
| `/usage`       | `/cost`    | Show token usage              |
| `/insights`    |            | Usage analytics               |
| `/skills`      |            | Browse/install skills         |
| `/background`  | `/bg`      | Manage background processes   |
| `/plan`        |            | Generate implementation plan  |
| `/rollback`    |            | Restore filesystem checkpoint |
| `/verbose`     |            | Toggle debug output           |
| `/reasoning`   |            | Set reasoning effort          |
| `/yolo`        |            | Toggle approval bypass        |
| `/btw`         |            | Ephemeral side question       |
| `/stop`        |            | Kill current agent run        |
| `/queue`       |            | Queue next prompt             |
| `/browser`     |            | Interactive browser session   |
| `/history`     | `/resume`  | Session browser               |
| `/skin`        |            | Switch CLI theme              |

---

### 6.5 Setup Wizard (hermes_cli/setup.py)

Modular interactive wizard with independent sections:

1. **Model & Provider** — Select AI provider, enter API keys, choose model
2. **Terminal Backend** — Choose execution environment
3. **Agent Settings** — Max iterations, compression, session policies
4. **Messaging Platforms** — Configure Telegram, Discord, Slack, etc.
5. **Tools** — TTS, STT, web search, image generation, browser

Features:

- Live credential validation
- Real-time model list fetching from provider APIs
- Automatic OpenClaw migration detection
- Atomic config file writes

---

### 6.6 Model Catalog (hermes_cli/models.py)

Provider-specific model lists:

```python
_PROVIDER_MODELS = {
    "nous": ["anthropic/claude-opus-4.6", "anthropic/claude-sonnet-4.6", ...],  # 25+
    "openrouter": ["anthropic/claude-opus-4.6", "google/gemini-3-flash", ...],  # 30+
    "anthropic": ["claude-opus-4-6", "claude-sonnet-4-6", ...],
    "openai": ["gpt-5", "gpt-5.4-mini", "gpt-4.1", "gpt-4o", ...],
    "copilot": ["gpt-5.4", "gpt-5.4-mini", "gpt-5.3-codex", ...],
    "huggingface": [...],
    "minimax": [...],
    "kimi-coding": [...],
    "alibaba": [...],
    "deepseek": [...],
    # ... more providers
}
```

Features:

- Dynamic fetching via provider `/models` endpoints
- Curated lists used when live probe returns fewer models
- Fuzzy matching for typo correction
- Validation against provider catalog

---

### 6.7 Skin/Theme Engine (hermes_cli/skin_engine.py)

Data-driven CLI visual customization — no code changes needed.

**Customizable Elements:**

| Element                          | Key                      | Used By           |
| -------------------------------- | ------------------------ | ----------------- |
| Banner border/title/accent       | `colors.*`               | banner.py         |
| Response box border              | `colors.response_border` | cli.py            |
| Spinner faces (waiting/thinking) | `spinner.*`              | display.py        |
| Spinner verbs/wings              | `spinner.*`              | display.py        |
| Tool output prefix               | `tool_prefix`            | display.py        |
| Per-tool emojis                  | `tool_emojis`            | display.py        |
| Agent name/welcome/prompt        | `branding.*`             | banner.py, cli.py |

**Built-in Skins:** default, ares, mono, slate, poseidon, sisyphus, charizard

**User Skins:** Drop `~/.hermes/skins/<name>.yaml` and activate with `/skin <name>`

---

## 7. Tool System

### 7.1 Terminal Tool (tools/terminal_tool.py)

Shell command execution across multiple backends.

```python
def terminal_tool(
    command: str,
    background: bool = False,
    timeout: Optional[int] = None,
    task_id: Optional[str] = None,
    force: bool = False,        # Skip approval for dangerous commands
    workdir: Optional[str] = None,
    check_interval: Optional[int] = None,  # Background task polling
    pty: bool = False,
) -> str  # JSON result
```

**Features:**

- Multi-backend: Selects based on `TERMINAL_ENV` (local/docker/ssh/modal/daytona/singularity)
- Per-task_id sandboxes with thread-safe creation locks
- Dangerous command routing through approval system
- Background task support with file-based IPC
- Interrupt handling — polls `is_interrupted()` during execution
- Auto-cleanup daemon thread for idle environments (>300s)
- Disk usage warnings at configurable threshold

---

### 7.2 File Tools (tools/file_tools.py)

Safe file operations with size guards and sensitive path protection.

- `read_file_tool(path, offset, limit)` — Read with pagination (default 100K char limit)
- `write_file_tool(path, content)` — Write with approval for sensitive paths
- `edit_file_tool(path, old_text, new_text)` — String replacement editing
- `list_files_tool(path)` — Directory listing
- `search_files_tool(pattern, path)` — Glob/regex file search

**Safety:**

- Device path blocklist (`/dev/zero`, `/dev/stdin`, etc.)
- Read dedup tracking — returns stub on re-read if mtime unchanged
- Sensitive path blocking: `/etc/`, `/boot/`, `~/.ssh` without approval
- Prompt injection protection for known dangerous paths

---

### 7.3 Web Tools (tools/web_tools.py)

Web search and content extraction.

- `web_search_tool(query, limit)` — Search via configurable backend
- `web_extract_tool(urls, format)` — Extract content from URLs
- `web_crawl_tool(url, ins

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