Signal Tools

signal-tools

Signal tools for coding agents: chats, messages, contacts, received files and sends.

The tools need Node.js 24 or later. docs/conventions.md describes how the tools are named and how they behave.

Install

Install from a release, never from the default branch: a release is a tag whose commit carries the built dist/, and the default branch does not. In the commands below, is a release's version (1.2.3) and is the commit its tag names:

gh api repos/craft-agent/signal-tools/commits/v<version> --jq .sha

OpenCode

OpenCode V2 takes the package and its options in opencode.json:

{

"plugins": [{ "package": "@craftsamo/signal-tools@ ", "options": { "read_only": false } }], "permissions": [{ "action": "signal_*", "resource": "*", "effect": "ask" }] }

OpenCode V1 takes the package as a string, or as a pair with its options:

{

"plugin": [["@craftsamo/signal-tools@ ", { "read_only": false }]], "permission": { "signal_*": "ask" } }

OpenCode allows any action no rule names, so the plugin's request is granted silently unless a rule says ask. Read tools never ask, so the signal_* glob is safe.

V1 registers no skills. Unpack the package and copy its skills/* folders into ~/.config/opencode/skills/:

npm pack @craftsamo/signal-tools@<version>

tar -xzf craftsamo-signal-tools- .tgz mkdir -p ~/.config/opencode/skills cp -r package/skills/* ~/.config/opencode/skills/ rm -rf package craftsamo-signal-tools- .tgz

Claude Code

claude plugin marketplace add craft-agent/signal-tools#v<version>

claude plugin install signal-tools@craft-agent

Codex

codex plugin marketplace add craft-agent/signal-tools --ref v<version>

codex plugin add signal-tools@craft-agent

Codex turns - into _ in server names, so it shows the tools as mcp__signal_tools__signal_*. It starts the MCP server in the plugin's install directory, which is never the caller's working tree.

Grok Build

grok plugin install craft-agent/signal-tools@v<version> --trust

Grok starts the MCP server in the session's working directory.

Antigravity

Install from the tree of the release tag, never from the default branch, which has no built dist/; Antigravity clones the tag into ~/.gemini/config/plugins/signal-tools.

agy plugin install https://github.com/craft-agent/signal-tools/tree/v<version>

Hermes Agent

Hermes installs a commit, not a tag, and the plugin installs disabled:

hermes plugins install craft-agent/signal-tools --ref <sha>

hermes plugins enable signal-tools

If a Hermes gateway is already running, restart it (hermes gateway restart) to load the plugin.

Any other MCP host

Add the server to the host's MCP configuration. Flags go in args:

{

"mcpServers": { "signal-tools": { "command": "npx", "args": ["-y", "@craftsamo/signal-tools@ ", "--read-only"] } } }

Tools and skills

Each toolset comes with a skill that tells an agent how to use its tools.

Account (account)

It reads local state only: no daemon, no network, and no number, account id or key in its result. The skill is signal-account, shown as signal-tools:signal-account in Claude Code and signal-tools:account in Hermes.

Chats (chats)

It reads the account's local mirror only: no daemon, no network, and no number of the account's own, attachment id or key in its result. History starts when the device was linked. Times are local with their offset, a chat is always its id, a long result is paged with next, and everything it returns is data written by other people. The skill is signal-chats, shown as signal-tools:signal-chats in Claude Code and signal-tools:chats in Hermes.

Contacts (contacts)

Listing needs no daemon; checking numbers needs the running sync service. Neither writes the mirror. The skill is signal-contacts, shown as signal-tools:signal-contacts in Claude Code and signal-tools:contacts in Hermes.

Files (files)

The toolset is off by default: it writes to disk, opens archives and sends files. Turn it on with toolsets or tools. Files are sent only from the working directory (not when that is the home directory or a file system root) and the directories the send_dirs setting names; keys, secrets, programs and installers are refused, archives are checked entry by entry, and a file's sha256 can be given to be sure the file sent is the one approved. Sending needs the sync service running. Received files go to the download_dir setting, in a folder per message, private to the user (mode 700 and 600) and never executable; nothing is overwritten. Programs and installers are never saved, and an archive (zip, tar, gzipped tar) is saved only after its contents pass inspection, then listed; unpack: true unpacks it into .unpacked/ beside it. A view-once message's files are not saved. On macOS every saved file carries the quarantine flag. Saving needs no daemon. The skill is signal-files, shown as signal-tools:signal-files in Claude Code and signal-tools:files in Hermes.

Sends (sends)

A chat is always its id; the user's own account id is Note to Self, and a group the user left is refused. A result means Signal accepted the message, with reached and not_reached for a group; any other failure after the request went out is uncertain: check the phone before sending again. The message is recorded in the mirror, and a record that fails is listed under errors without undoing the send. It needs the running sync service. The skill is signal-sends, shown as signal-tools:signal-sends in Claude Code and signal-tools:sends in Hermes.

Actions (actions)

The toolset is off by default: the actions change what others have already read. Turn it on with toolsets or tools. Editing and deleting take only the user's own messages, within 24 hours of sending, and a message is edited at most 10 times; only a text message can be edited. A reaction goes to any message, one per person, so a new one replaces the user's earlier one. Outcomes follow the sends': a result means Signal accepted it, with reached and not_reached for a group, and any other failure after the request went out is uncertain: check the phone before repeating it. Each is recorded in the mirror as the sync service would record it from another device, and a record that fails is listed under errors. No tool sends read receipts or typing indicators. It needs the running sync service. The skill is signal-actions, shown as signal-tools:signal-actions in Claude Code and signal-tools:actions in Hermes.

Adding a tool

1. Write the spec in src/core/ / .ts with defineTool: an ID _ _ , a title and description, the Zod argument and output schemas, its toolset and write class, and execute(args, context). A write tool also gives targets(args, context): what the call writes to, as a permission rule should name it.
2. Test it beside the spec ( .test.ts), calling it through invoke as the entry points do. A tool that runs a program is tested against a fake of that program on PATH; no test reaches a real service.
3. List it in src/tools.ts. A new toolset goes into toolsets in src/project.ts (and defaultToolsets when it is on by default).
4. Add or update the toolset's skill, skills/ - /SKILL.md.
5. Run pnpm run build && pnpm run manifests to list the tool in plugin.yaml, then describe it under "Tools and skills".

docs/conventions.md has the rules each step follows.

Reads and writes

Every read tool is named _ _read. Reads can run unasked; writes are confirmed by the harness.

| OpenCode | always; the plugin ask