From 331e4dd614b8af37327b84eb498ec9e5b880f785 Mon Sep 17 00:00:00 2001 From: figmar Date: Sun, 9 Aug 2026 08:19:23 +0800 Subject: [PATCH] Publish hermes-skills-mcp via gitea-publish skill --- native-mcp/SKILL.md | 357 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 357 insertions(+) create mode 100644 native-mcp/SKILL.md diff --git a/native-mcp/SKILL.md b/native-mcp/SKILL.md new file mode 100644 index 0000000..ca38967 --- /dev/null +++ b/native-mcp/SKILL.md @@ -0,0 +1,357 @@ +--- +name: native-mcp +description: "MCP client: connect servers, register tools (stdio/HTTP)." +version: 1.0.0 +author: Hermes Agent +license: MIT +platforms: [linux, macos, windows] +metadata: + hermes: + tags: [MCP, Tools, Integrations] + related_skills: [mcporter] +--- + +# Native MCP Client + +Hermes Agent has a built-in MCP client that connects to MCP servers at startup, discovers their tools, and makes them available as first-class tools the agent can call directly. No bridge CLI needed -- tools from MCP servers appear alongside built-in tools like `terminal`, `read_file`, etc. + +## When to Use + +Use this whenever you want to: +- Connect to MCP servers and use their tools from within Hermes Agent +- Add external capabilities (filesystem access, GitHub, databases, APIs) via MCP +- Run local stdio-based MCP servers (npx, uvx, or any command) +- Connect to remote HTTP/StreamableHTTP MCP servers +- Have MCP tools auto-discovered and available in every conversation + +For ad-hoc, one-off MCP tool calls from the terminal without configuring anything, see the `mcporter` skill instead. + +## Prerequisites + +- **mcp Python package** -- optional dependency; install with `pip install mcp`. If not installed, MCP support is silently disabled. +- **Node.js** -- required for `npx`-based MCP servers (most community servers) +- **uv** -- required for `uvx`-based MCP servers (Python-based servers) + +Install the MCP SDK: + +```bash +pip install mcp +# or, if using uv: +uv pip install mcp +``` + +## Quick Start + +Add MCP servers to `~/.hermes/config.yaml` under the `mcp_servers` key: + +```yaml +mcp_servers: + time: + command: "uvx" + args: ["mcp-server-time"] +``` + +Restart Hermes Agent. On startup it will: +1. Connect to the server +2. Discover available tools +3. Register them with the prefix `mcp_time_*` +4. Inject them into all platform toolsets + +You can then use the tools naturally -- just ask the agent to get the current time. + +## Configuration Reference + +Each entry under `mcp_servers` is a server name mapped to its config. There are two transport types: **stdio** (command-based) and **HTTP** (url-based). + +### Stdio Transport (command + args) + +```yaml +mcp_servers: + server_name: + command: "npx" # (required) executable to run + args: ["-y", "pkg-name"] # (optional) command arguments, default: [] + env: # (optional) environment variables for the subprocess + SOME_API_KEY: "value" + timeout: 120 # (optional) per-tool-call timeout in seconds, default: 120 + connect_timeout: 60 # (optional) initial connection timeout in seconds, default: 60 +``` + +### HTTP Transport (url) + +```yaml +mcp_servers: + server_name: + url: "https://my-server.example.com/mcp" # (required) server URL + headers: # (optional) HTTP headers + Authorization: "Bearer sk-..." + timeout: 180 # (optional) per-tool-call timeout in seconds, default: 120 + connect_timeout: 60 # (optional) initial connection timeout in seconds, default: 60 +``` + +### All Config Options + +| Option | Type | Default | Description | +|-------------------|--------|---------|---------------------------------------------------| +| `command` | string | -- | Executable to run (stdio transport, required) | +| `args` | list | `[]` | Arguments passed to the command | +| `env` | dict | `{}` | Extra environment variables for the subprocess | +| `url` | string | -- | Server URL (HTTP transport, required) | +| `headers` | dict | `{}` | HTTP headers sent with every request | +| `timeout` | int | `120` | Per-tool-call timeout in seconds | +| `connect_timeout` | int | `60` | Timeout for initial connection and discovery | + +Note: A server config must have either `command` (stdio) or `url` (HTTP), not both. + +## How It Works + +### Startup Discovery + +When Hermes Agent starts, `discover_mcp_tools()` is called during tool initialization: + +1. Reads `mcp_servers` from `~/.hermes/config.yaml` +2. For each server, spawns a connection in a dedicated background event loop +3. Initializes the MCP session and calls `list_tools()` to discover available tools +4. Registers each tool in the Hermes tool registry + +### Tool Naming Convention + +MCP tools are registered with the naming pattern: + +``` +mcp_{server_name}_{tool_name} +``` + +Hyphens and dots in names are replaced with underscores for LLM API compatibility. + +Examples: +- Server `filesystem`, tool `read_file` → `mcp_filesystem_read_file` +- Server `github`, tool `list-issues` → `mcp_github_list_issues` +- Server `my-api`, tool `fetch.data` → `mcp_my_api_fetch_data` + +### Auto-Injection + +After discovery, MCP tools are automatically injected into all `hermes-*` platform toolsets (CLI, Discord, Telegram, etc.). This means MCP tools are available in every conversation without any additional configuration. + +### Connection Lifecycle + +- Each server runs as a long-lived asyncio Task in a background daemon thread +- Connections persist for the lifetime of the agent process +- If a connection drops, automatic reconnection with exponential backoff kicks in (up to 5 retries, max 60s backoff) +- On agent shutdown, all connections are gracefully closed + +### Idempotency + +`discover_mcp_tools()` is idempotent -- calling it multiple times only connects to servers that aren't already connected. Failed servers are retried on subsequent calls. + +## Transport Types + +### Stdio Transport + +The most common transport. Hermes launches the MCP server as a subprocess and communicates over stdin/stdout. + +```yaml +mcp_servers: + filesystem: + command: "npx" + args: ["-y", "@modelcontextprotocol/server-filesystem", "/home/user/projects"] +``` + +The subprocess inherits a **filtered** environment (see Security section below) plus any variables you specify in `env`. + +### HTTP / StreamableHTTP Transport + +For remote or shared MCP servers. Requires the `mcp` package to include HTTP client support (`mcp.client.streamable_http`). + +```yaml +mcp_servers: + remote_api: + url: "https://mcp.example.com/mcp" + headers: + Authorization: "Bearer sk-..." +``` + +If HTTP support is not available in your installed `mcp` version, the server will fail with an ImportError and other servers will continue normally. + +## Security + +### Environment Variable Filtering + +For stdio servers, Hermes does NOT pass your full shell environment to MCP subprocesses. Only safe baseline variables are inherited: + +- `PATH`, `HOME`, `USER`, `LANG`, `LC_ALL`, `TERM`, `SHELL`, `TMPDIR` +- Any `XDG_*` variables + +All other environment variables (API keys, tokens, secrets) are excluded unless you explicitly add them via the `env` config key. This prevents accidental credential leakage to untrusted MCP servers. + +```yaml +mcp_servers: + github: + command: "npx" + args: ["-y", "@modelcontextprotocol/server-github"] + env: + # Only this token is passed to the subprocess + GITHUB_PERSONAL_ACCESS_TOKEN: "ghp_..." +``` + +### Credential Stripping in Error Messages + +If an MCP tool call fails, any credential-like patterns in the error message are automatically redacted before being shown to the LLM. This covers: + +- GitHub PATs (`ghp_...`) +- OpenAI-style keys (`sk-...`) +- Bearer tokens +- Generic `token=`, `key=`, `API_KEY=`, `password=`, `secret=` patterns + +## Troubleshooting + +### "MCP SDK not available -- skipping MCP tool discovery" + +The `mcp` Python package is not installed. Install it: + +```bash +pip install mcp +``` + +### "No MCP servers configured" + +No `mcp_servers` key in `~/.hermes/config.yaml`, or it's empty. Add at least one server. + +### "Failed to connect to MCP server 'X'" + +Common causes: +- **Command not found**: The `command` binary isn't on PATH. Ensure `npx`, `uvx`, or the relevant command is installed. +- **Package not found**: For npx servers, the npm package may not exist or may need `-y` in args to auto-install. +- **Timeout**: The server took too long to start. Increase `connect_timeout`. +- **Port conflict**: For HTTP servers, the URL may be unreachable. + +### "MCP server 'X' requires HTTP transport but mcp.client.streamable_http is not available" + +Your `mcp` package version doesn't include HTTP client support. Upgrade: + +```bash +pip install --upgrade mcp +``` + +### Tools not appearing + +- Check that the server is listed under `mcp_servers` (not `mcp` or `servers`) +- Ensure the YAML indentation is correct +- Look at Hermes Agent startup logs for connection messages +- Tool names are prefixed with `mcp_{server}_{tool}` -- look for that pattern + +### Connection keeps dropping + +The client retries up to 5 times with exponential backoff (1s, 2s, 4s, 8s, 16s, capped at 60s). If the server is fundamentally unreachable, it gives up after 5 attempts. Check the server process and network connectivity. + +## Examples + +### Time Server (uvx) + +```yaml +mcp_servers: + time: + command: "uvx" + args: ["mcp-server-time"] +``` + +Registers tools like `mcp_time_get_current_time`. + +### Filesystem Server (npx) + +```yaml +mcp_servers: + filesystem: + command: "npx" + args: ["-y", "@modelcontextprotocol/server-filesystem", "/home/user/documents"] + timeout: 30 +``` + +Registers tools like `mcp_filesystem_read_file`, `mcp_filesystem_write_file`, `mcp_filesystem_list_directory`. + +### GitHub Server with Authentication + +```yaml +mcp_servers: + github: + command: "npx" + args: ["-y", "@modelcontextprotocol/server-github"] + env: + GITHUB_PERSONAL_ACCESS_TOKEN: "ghp_xxxxxxxxxxxxxxxxxxxx" + timeout: 60 +``` + +Registers tools like `mcp_github_list_issues`, `mcp_github_create_pull_request`, etc. + +### Remote HTTP Server + +```yaml +mcp_servers: + company_api: + url: "https://mcp.mycompany.com/v1/mcp" + headers: + Authorization: "Bearer sk-xxxxxxxxxxxxxxxxxxxx" + X-Team-Id: "engineering" + timeout: 180 + connect_timeout: 30 +``` + +### Multiple Servers + +```yaml +mcp_servers: + time: + command: "uvx" + args: ["mcp-server-time"] + + filesystem: + command: "npx" + args: ["-y", "@modelcontextprotocol/server-filesystem", "/tmp"] + + github: + command: "npx" + args: ["-y", "@modelcontextprotocol/server-github"] + env: + GITHUB_PERSONAL_ACCESS_TOKEN: "ghp_xxxxxxxxxxxxxxxxxxxx" + + company_api: + url: "https://mcp.internal.company.com/mcp" + headers: + Authorization: "Bearer sk-xxxxxxxxxxxxxxxxxxxx" + timeout: 300 +``` + +All tools from all servers are registered and available simultaneously. Each server's tools are prefixed with its name to avoid collisions. + +## Sampling (Server-Initiated LLM Requests) + +Hermes supports MCP's `sampling/createMessage` capability — MCP servers can request LLM completions through the agent during tool execution. This enables agent-in-the-loop workflows (data analysis, content generation, decision-making). + +Sampling is **enabled by default**. Configure per server: + +```yaml +mcp_servers: + my_server: + command: "npx" + args: ["-y", "my-mcp-server"] + sampling: + enabled: true # default: true + model: "gemini-3-flash" # model override (optional) + max_tokens_cap: 4096 # max tokens per request + timeout: 30 # LLM call timeout (seconds) + max_rpm: 10 # max requests per minute + allowed_models: [] # model whitelist (empty = all) + max_tool_rounds: 5 # tool loop limit (0 = disable) + log_level: "info" # audit verbosity +``` + +Servers can also include `tools` in sampling requests for multi-turn tool-augmented workflows. The `max_tool_rounds` config prevents infinite tool loops. Per-server audit metrics (requests, errors, tokens, tool use count) are tracked via `get_mcp_status()`. + +Disable sampling for untrusted servers with `sampling: { enabled: false }`. + +## Notes + +- MCP tools are called synchronously from the agent's perspective but run asynchronously on a dedicated background event loop +- Tool results are returned as JSON with either `{"result": "..."}` or `{"error": "..."}` +- The native MCP client is independent of `mcporter` -- you can use both simultaneously +- Server connections are persistent and shared across all conversations in the same agent process +- Adding or removing servers requires restarting the agent (no hot-reload currently)