add-mattermost

add-mattermost is a skill for Claude Code from nanocoai/nanoclaw. It costs 38 tokens per session (4,417 once invoked), scanned B, original, MIT.

A Mattermost bot connection for NanoClaw. Mattermost is a team messaging service that can be hosted by your organization or used in the cloud.

In plain words
What is it for?
Use it for direct messages, channels, threaded discussions, file sharing, reactions, and interactive approval cards.
Why use it?
It connects the agent to existing Mattermost conversations and can reuse a local server when one is available.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: reads .claude/ paths.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is bash setup/lib/restart.sh.

Good fit Use it for direct messages, channels, threaded discussions, file sharing, reactions, and interactive approval cards.

Compare 6 skills from other repositories ↓
About the project

NanoClaw is an AI assistant that runs agents inside separate Linux containers, isolating their files and execution environments. People use it to connect agents to messaging services and run assistants with memory and scheduled jobs. The catalogue contains skills and instructions for extending or operating NanoClaw.

nanocoai/nanoclaw · 30,736 stars · on GitHub · nanoclaw.dev

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/nanocoai/nanoclaw
agentmods
npx agentmods add skills/nanocoai/nanoclaw/add-mattermost

Made for: Claude Code.

Wrote 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.

agentmods badge for add-mattermost

README.md
[![agentmods](https://agentmods.dev/badge/skills/nanocoai/nanoclaw/add-mattermost/github.svg)](https://agentmods.dev/skills/nanocoai/nanoclaw/add-mattermost)
Your own site
<a href="https://agentmods.dev/skills/nanocoai/nanoclaw/add-mattermost"><img src="https://agentmods.dev/badge/skills/nanocoai/nanoclaw/add-mattermost/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for add-mattermost

Your own site · 80×15
<a href="https://agentmods.dev/skills/nanocoai/nanoclaw/add-mattermost"><img src="https://agentmods.dev/badge/skills/nanocoai/nanoclaw/add-mattermost.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,417 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 5 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 114
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 227
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 233
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • medium Data Exfiltration · line 240
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
  • medium Data Exfiltration · line 336
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00038 $0.04417
Opus 5 $0.00019 $0.02209
Sonnet 5 $0.00008 $0.00883
Haiku 4.5 $0.00004 $0.00442

Measured 11d ago against content hash 53a842a99d65, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

add-mattermost scanned grade B with 2 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 11d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/discover-server.mjs, scripts/remove-base-url.mjs, scripts/select-server.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

curl -sf -X POST "{{base_url}}/api/v4/channels/direct" -H "Authorization: Bearer {{bot_token}}" -H "Content-Type: application/json" -d '["{{owner_user_id}}","{{bot_user_id}}"]' | jq -er '"mattermost:" + .id'

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

for attempt in $(seq 1 30); do curl -fsS --connect-timeout 1 --max-time 1 http://localhost:8065/api/v4/system/ping >/dev/null && exit 0; sleep 1; done; docker compose -f .nanoclaw/mattermost/compose.yml logs --tail 100 m
.claude/skills/add-mattermost/SKILL.md · 383 lines

How it starts

The opening of the file, as written. The whole thing — 383 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Add Mattermost Channel

Adds Mattermost DMs, channels, threads, files, reactions, and interactive approval cards. Messages arrive over Mattermost's WebSocket; card clicks return to NanoClaw over an authenticated HTTP callback. Every step is safe to re-run.

Discover the server first

Do this before installing the adapter or asking for a URL. The goal is to reuse a healthy Mattermost the user already has and establish one canonical base URL.

  1. Check an existing MATTERMOST_BASE_URL in the current environment and NanoClaw env/config files. Do not print tokens or dump whole env files.
  2. Probe likely local URLs, at least http://localhost:8065 and http://127.0.0.1:8065, using GET /api/v4/system/ping. A listening port alone is not evidence that the service is Mattermost.
  3. Inspect Docker/Compose for Mattermost containers. If a matching container exists but is stopped, offer to start it; do not start or recreate it without the user's approval.
  4. If you find a healthy server, show its URL. Ask the user to use this server, enter a different URL, or create the local evaluation server. Do not select a server automatically. Treat the localhost and 127.0.0.1 endpoints for the same container as one server.
  5. If nothing local is found, ask whether the user has a remote Mattermost. If not, offer the local evaluation installation in LOCAL_SERVER.md. Read that file only for local server discovery, repair, or installation.

Set MATTERMOST_BASE_URL to the chosen canonical URL (scheme included, no trailing slash), then use that exact hostname in browser/Desktop setup. Do not silently install Mattermost: it runs containers, binds a port, and persists data, so show what will be created and get approval first.

Apply

1. Detect the server

Test the configured URL and the standard local URLs. A detected server is only a suggestion. The user must select the server.

node .claude/skills/add-mattermost/scripts/discover-server.mjs

Read the full file on GitHub · 383 lines

Files

What ships with it

7 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.

Changes

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.

  1. 11d ago First seen · 383 lines · 38 tokens per session scan B 53a842a99d65

Subscribe to this mod's changes

add-mattermost is a skill published in the GitHub repository nanocoai/nanoclaw (30,736 stars, last pushed today), licensed MIT. It adds 38 tokens to every session and 4,417 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 2 findings (sends data to an external url, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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