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/holon-run/uxc/slack-openapi-skillnpx skills add holon-run/uxc --skill slack-openapi-skillgit clone --depth 1 https://github.com/holon-run/uxcWrote 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/holon-run/uxc/slack-openapi-skill)<a href="https://agentmods.dev/skills/holon-run/uxc/slack-openapi-skill"><img src="https://agentmods.dev/badge/skills/holon-run/uxc/slack-openapi-skill.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 | $0.00031 | $0.01805 |
| Opus 5 | $0.00015 | $0.00903 |
| Sonnet 5 | $0.00006 | $0.00361 |
| Haiku 4.5 | $0.00003 | $0.00180 |
Grade A, and why
slack-openapi-skill 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 5d 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 — 183 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Slack Web API Skill
Use this skill to run Slack Web API operations through uxc + OpenAPI.
Reuse the uxc skill for shared execution, auth, and error-handling guidance.
Prerequisites
uxcis installed and available inPATH.- Network access to
https://slack.com/api. - Access to the curated OpenAPI schema URL:
https://raw.githubusercontent.com/holon-run/uxc/main/skills/slack-openapi-skill/references/slack-web.openapi.json
- A Slack bot token and, for selected thread/history reads, an optional user token.
Scope
This skill covers a Messaging Core surface:
- auth validation
- channel lookup and inspection
- conversation history reads
- thread replies reads
- posting messages, including replies via
thread_ts - adding reactions
This skill does not cover:
- Slack OAuth app installation flow
- file upload flows
users.*,admin.*, orusergroups.*method families
Subscribe / Socket Mode Status
Slack inbound events can be delivered through Socket Mode. uxc now has a built-in Slack Socket Mode transport, but this skill still treats it as a limited event-ingest path rather than a fully packaged workflow surface.
Current uxc subscribe status:
- Slack Web API request/response calls are supported by this skill
- a live Socket Mode smoke test succeeded with the built-in transport:
uxc subscribe start https://slack.com/api --transport slack-socket-mode --auth slack-app --sink file:...- the runtime opened a fresh temporary WebSocket URL automatically
- the initial Slack
helloframe was received
- a real inbound message event was validated end-to-end:
- while the Socket Mode job was running, a live Slack message event was delivered as an
events_apienvelope - the sink recorded the message payload and
ack_sent=true
- while the Socket Mode job was running, a live Slack message event was delivered as an
What the current built-in transport already handles:
- app-level
xapp-...auth via--auth - automatic
apps.connections.openbefore each connect attempt - raw Socket Mode frame capture
- automatic ack for envelopes that carry
envelope_id
What ships with it
4 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.
- 5d ago First seen · 183 lines · 31 tokens per session scan A e3358b84bc78
slack-openapi-skill is a skill published in the GitHub repository holon-run/uxc (113 stars, last pushed 26d ago), licensed MIT. It adds 31 tokens to every session and 1,805 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 2026-08-30.
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