slack-skills-plugin is a plugin that connects coding agents to Slack through a Slack MCP server and provides Slack-focused skills for users and developers. It is used with Claude Code, Cursor, Codex, and other coding agents to work with Slack and build Slack applications. The catalogue entries are the plugin's included skills, commands, MCP server, instructions, and settings.
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 slackapi/slack-skills-plugin --skill slack-apigit clone --depth 1 https://github.com/slackapi/slack-skills-pluginWrote 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/slackapi/slack-skills-plugin/slack-api)<a href="https://agentmods.dev/skills/slackapi/slack-skills-plugin/slack-api"><img src="https://agentmods.dev/badge/skills/slackapi/slack-skills-plugin/slack-api/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/slackapi/slack-skills-plugin/slack-api"><img src="https://agentmods.dev/badge/skills/slackapi/slack-skills-plugin/slack-api.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
- Socket pass
- Snyk warn
SkillSpector: 3 findings, 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 Excessive Agency · line 23 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
- medium Data Exfiltration · line 119 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 119 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 | $0.00109 | $0.03256 |
| Opus 5.5 | $0.00044 | $0.01302 |
| Sonnet 5.5 | $0.00022 | $0.00651 |
| Haiku 4.5 | $0.00011 | $0.00326 |
Grade A, and why
slack-api scanned grade A with 1 finding 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
You do not need the CLI to call a method. Get a token of the type you determined above from the app's **OAuth & Permissions** page in the Slack app config (`https://api.slack.com/apps` → your app → **OAuth & Permissions* How it starts
The opening of the file, as written. The whole thing — 208 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Slack Web API
Help the developer discover the right Web API method, read its contract, and call it correctly. Slack exposes hundreds of methods named in family.method dot notation (e.g. chat.postMessage, conversations.history) at https://slack.com/api/<method>. Every method's doc page follows a fixed URL pattern, so the contract for any method is always one fetch away.
If $0 is provided, it is either a full method.name (jump to Step 2 to read its contract) or a family name (go to Step 1 and find it in the index).
Critical rules:
- Verify a method name and its required scopes against its doc page before calling it — never invent method names or guess scopes. Method names use
family.methoddot notation.- Every response has a top-level
okboolean. Always checkokbefore using the result; onok: false, read theerrorstring.- Method names, scopes, rate tiers, and arguments come from the live doc page (
https://docs.slack.dev/reference/methods/<method-lowercased>.md). The docs are the source of truth — discover from the live index, read the contract from the method's own page.
DO NOT rules:
- DO NOT assume a method is GET — many are POST. Check the doc page.
- DO NOT hardcode bearer tokens into committed code or share them in plain text.
- DO NOT use deprecated methods (
files.upload,dialog.open,rtm.*,oauth.access,search.*,stars.*,reminders.*) without checking the replacement — a deprecated method's own doc page names what supersedes it; prefer the replacement for new apps.- DO NOT paginate by incrementing a page number — Slack uses opaque cursors (see Step 5).
Execution posture — run reads, confirm writes:
- Read-only methods (
*.list,*.info,*.history,conversations.members,auth.test, etc.) may be run directly to help the developer.- State-changing or destructive methods (
chat.postMessage/update/delete, any*.delete/*.remove/*.kick/*.archive, and alladmin.*) — prepare the exact command and confirm with the developer before running it.
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 · 208 lines · 109 tokens per session scan A 341eb0389a7f
slack-api is a skill published in the GitHub repository slackapi/slack-skills-plugin (149 stars, last pushed yesterday), licensed MIT. It adds 109 tokens to every session and 3,256 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
api-and-interface-design
Guides stable API and interface design. Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints, defining type contracts between modules, or establishing boundaries between frontend and backend.
awesome-performance-audit
Read-only performance and reliability audit: event loop, backpressure, memory and CPU, timeouts, retries, queues, Core Web Vitals, bundles, with a verdict. Use when something is slow, memory climbs or latency spikes.
awesome-error-standards
Applies consistent error handling: typed errors, operational vs programmer errors, API error envelopes, HTTP status mapping, user-facing messages. Use when adding or refactoring error handling or designing an error contract.
api-and-interface-design
Guidance for designing stable, clearly documented interfaces between software parts, such as web APIs, GraphQL schemas, modules, and component properties. It covers defining the contract first, limiting accidental dependencies, and planning safe changes.
deprecation-and-migration
A guide for retiring old code, systems, or interfaces and moving users to replacements. Deprecation means marking something as no longer preferred; migration means switching its users safely.
awesome-api-design
Designs or reviews an HTTP API's shape before code: resources, versioning, pagination, idempotency, filtering. Use when asked to design an API or an endpoint.