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 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/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.
<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="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
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 →
- medium Data Exfiltration · line 78 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.
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 5.1 | $0.00031 | $0.01805 |
| Opus 5.5 | $0.00012 | $0.00722 |
| Sonnet 5.5 | $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 1mo 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.
- 1mo 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 (119 stars, last pushed 1mo ago), licensed MIT. It adds 31 tokens to every session and 1,805 once invoked, about $0.0001 per session on Opus 5.5. 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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