Agenvoy
Tool Extension
Agenvoy supports four ways to add new tools beyond the built-in set: auto-generation from a capability gap, script tools, API tools, and MCP tools.
Auto-generation (Capability Gap)
When a user request needs live external data (weather, currency, stock, geocoding, translation, etc.) and no existing tool covers it, the agent creates the tool on the spot, then runs it to answer. No programming required.
The system prompt Capability Gap section drives the sequence:
| Step | Action |
|---|---|
| 1. Find a suitable API | api_public_api_list(type=category) to pick relevant categories, select best candidate (prefer no-auth + HTTPS), then fetch_page the docs |
| 2. Create the script tool | mkdir the tool dir, then write_file a tool.json (name, description, schema) + script.py (stdin JSON to HTTP call to stdout JSON) |
| 3. Run and answer | Pipe the user query into the new script; if it fails, fix and retry (max 3) |
After creation, the tool persists at ~/.config/agenvoy/tools/script/<name>/ and is available in all future sessions. Auth-required APIs are handled via store_secret + keychain integration in the generated script.
Key constraints:
- The agent must never answer with raw
send_http_requestor inlinepython3 -c; it must write a reusable script to disk fetch_pageis allowed only for reading API documentation, not for fetching answer data- The generated
tool.jsonuses"always_allow": trueso the tool runs without confirmation on subsequent calls
Script tools (script_*)
Drop a Python / Node.js / shell script under extensions/scripts/<name>/ along with a tool.json descriptor. Agenvoy auto-registers it as script_<name> at startup.
extensions/scripts/my-tool/
├── tool.json # name, description, parameter schema, command
└── run.py # actual script
API tools (api_*)
Drop a JSON file under extensions/apis/<name>.json describing a REST endpoint. It auto-registers as api_<name>. Each api_<name> has its own per-name 1 s rate limiter (reserveAPISlot).
Confirm gate --- api_* tools are not prefix-exempt from confirmation. Users may define destructive endpoints (DELETE / POST writes), so agen cli confirms each call. Use agen run for batch auto-approval.
MCP tools (mcp__*)
Tools exposed by an MCP server are auto-registered as mcp__<server>__<tool>. MCP tool output is capped at 1 MiB per call to keep tool results within provider limits.