Extend Setup section with platform-specific installation instructions (#12)

Author: akolotov

README.md

@@ -12,9 +12,71 @@ Each skill is a self-contained directory of structured instructions and helper s
 
 ## Setup
 
-Each skill is a directory with a `SKILL.md` entry point and supporting docs/scripts. Integration depends on your agent platform.
+Each skill is a directory with a `SKILL.md` entry point and supporting docs/scripts. Integration depends on your agent platform — see examples below.
 
-See each skill's README for required environment variables and configuration.
+### Claude Code
+
+No separate MCP server configuration needed — it is set up automatically as part of the plugin installation.
+
+```sh
+claude plugin marketplace add blockscout/agent-skills
+claude plugin install blockscout-analysis@blockscout-ai
+```
+
+### Claude Desktop (Chat / Cowork / Code)
+
+Must be configured separately for Chat/Cowork and for Code by the same procedure.
+
+1. Choose **Customize** in the sidebar:
+
+   ![Customize in sidebar](assets/Claude-Add-Pluging-00-Custmize.png)
+
+2. Choose **Browse plugins** → **Personal** → **Add marketplace from GitHub**:
+
+   ![Add marketplace from GitHub](assets/Claude-Add-Pluging-01-Add-Marketplace.png)
+
+3. Enter the GitHub repo ID `blockscout/agent-skills` and press **Sync**:
+
+   ![Enter repo ID](assets/Claude-Add-Pluging-02-Marketplace-GitHub.png)
+
+4. The marketplace **blockscout-ai** will appear in the list of Personal plugins. Click **Install** on the Blockscout analysis plugin:
+
+   ![Install plugin](assets/Claude-Add-Pluging-03-Install-Plugin.png)
+
+5. Once installed, the plugin details are available in the **Customize** window:
+
+   ![Plugin info](assets/Claude-Add-Pluging-04-Plugin-Info.png)
+
+6. If the plugin has MCP servers associated, their info will be available in the **Connectors** sub-item:
+
+   ![Plugin connector](assets/Claude-Add-Pluging-05-Plugin-Connector.png)
+
+### Gemini CLI
+
+```sh
+gemini mcp add --transport http blockscout https://mcp.blockscout.com/mcp
+gemini skills install https://github.com/blockscout/agent-skills --path blockscout-analysis
+```
+
+### Codex CLI / Codex App
+
+Configure the MCP server first. For Codex App: **Settings** → **MCP Servers** → **Add server**.
+
+```sh
+codex mcp add blockscout --url https://mcp.blockscout.com/mcp
+```
+
+Then run `codex` and prompt:
+
+```plaintext
+$skill-installer Install the skill from https://github.com/blockscout/agent-skills, path `blockscout-analysis`
+```
+
+Restart Codex to pick up the skill. Before prompting, make sure that either `network_access` is allowed for the sandbox or "Full access" is granted.
+
+## Updating
+
+The skills and the underlying Blockscout infrastructure are under continuous development. Update the marketplace/plugin (Claude) or re-install the skill (Gemini, Codex) periodically to pick up the most recent versions.
 
 ## Packaging