Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/gaelic-ghost/socket/build-hermes-agent-extensionsnpx skills add gaelic-ghost/socket --skill build-hermes-agent-extensionsgit clone --depth 1 https://github.com/gaelic-ghost/socketWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/gaelic-ghost/socket/build-hermes-agent-extensions)<a href="https://agentmods.dev/skills/gaelic-ghost/socket/build-hermes-agent-extensions"><img src="https://agentmods.dev/badge/skills/gaelic-ghost/socket/build-hermes-agent-extensions.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00044 | $0.00956 |
| Opus 5 | $0.00022 | $0.00478 |
| Sonnet 5 | $0.00009 | $0.00191 |
| Haiku 4.5 | $0.00004 | $0.00096 |
Grade A, and why
build-hermes-agent-extensions scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Build Hermes Agent Extensions
Choose the owned extension surface before creating files. Hermes uses several unrelated plugin and integration systems; do not force them into one generic package.
Select the Surface
- Use a skill for instructions, existing commands, and progressive disclosure.
- Use MCP for an external tool server.
- Use a general Python plugin for registered tools, lifecycle hooks, slash commands, CLI commands, or bundled namespaced skills.
- Use a specialized provider/plugin surface for models, messaging platforms, memory, context engines, secrets, image/video generation, web search, or browser sessions.
- Use configuration for TTS commands, STT commands, shell hooks, MCP, and other explicitly config-driven surfaces.
- Use gateway hook directories for gateway event handlers.
- Use the desktop SDK or dashboard SDK only for their respective UI host; they do not share the Python plugin API.
- Use ACP when an editor or compatible client drives the agent; hand generic ACP implementation to
build-acp-agentand existing client setup tooperate-acp-agent-integration. - Use A2A when independently operated agents exchange discovered tasks; hand
operation to
operate-a2a-agent-integrationand use Hermes's specialized platform adapter only when extending its native A2A surface. - Use TUI gateway JSON-RPC or the OpenAI-compatible API server for custom programs that drive the agent without an ACP client.
- Modify Hermes core only when the feature belongs upstream and the official contributor guide selects that path.
Read references/extension-surface-map.md before implementing any surface beyond a skill or MCP declaration.
Implement a Standalone Python Plugin
For a third-party or project integration:
- Keep it in an independently installable repository or project/user plugin directory.
- Add
plugin.yamland a narrowregister(ctx)entry point. - Split schemas from handlers so model-visible contracts stay reviewable.
- Declare provided tools, hooks, commands, skills, and required environment only when they are actually registered or required.
- Keep credentials in Hermes/private environment configuration.
- Add unit tests for registration, schemas, handlers, redaction, and failure messages.
- Add an opt-in smoke test for the real backend.
- Require explicit enablement through
plugins.enabled; discovery alone must not execute third-party code. Test bundled, user, project, and pip discovery plus name-collision precedence when more than one source can provide it.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 82 lines · 44 tokens per session scan A 63e898574eba
build-hermes-agent-extensions is a skill published in the GitHub repository gaelic-ghost/socket (7 stars, last pushed 8d ago), licensed Apache-2.0. It adds 44 tokens to every session and 956 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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