docs: Add OpenCode install instructions

contents/docs/llm-analytics/installation/opencode.mdx

@@ -0,0 +1,130 @@
+---
+title: OpenCode LLM analytics installation
+platformIconName: IconOpenCode
+showStepsToc: true
+tableOfContents: [
+    {
+        url: 'prerequisites',
+        value: 'Prerequisites',
+        depth: 1,
+    },
+    {
+        url: 'install-the-plugin',
+        value: 'Install the plugin',
+        depth: 1,
+    },
+    {
+        url: 'configure-posthog',
+        value: 'Configure PostHog',
+        depth: 1,
+    },
+    {
+        url: 'start-opencode',
+        value: 'Start OpenCode',
+        depth: 1,
+    },
+    {
+        url: 'verify-traces-and-generations',
+        value: 'Verify traces and generations',
+        depth: 1,
+    },
+    {
+        url: 'configuration-options',
+        value: 'Configuration options',
+        depth: 1,
+    },
+]
+---
+
+[OpenCode](https://opencode.ai) is an open-source coding agent that runs in your terminal. The `opencode-posthog` plugin captures LLM generations, tool executions, and conversation traces as `$ai_generation`, `$ai_span`, and `$ai_trace` events and sends them to PostHog.
+
+## Prerequisites
+
+You need:
+
+- [OpenCode](https://opencode.ai/docs/) installed
+- A [PostHog account](https://us.posthog.com/signup) with a project API key
+
+## Install the plugin
+
+Add `opencode-posthog` to your `opencode.json`:
+
+```json
+{
+    "$schema": "https://opencode.ai/config.json",
+    "plugin": ["opencode-posthog"]
+}
+```
+
+The package installs automatically at startup and is cached in `~/.cache/opencode/node_modules/`.
+
+## Configure PostHog
+
+Set environment variables with your PostHog project API key and host. You can find these in your [PostHog project settings](https://us.posthog.com/settings/project).
+
+```bash
+export POSTHOG_API_KEY="<ph_project_api_key>"
+export POSTHOG_HOST="<ph_client_api_host>"
+```
+
+All other plugin configuration is also done with environment variables. If `POSTHOG_API_KEY` is not set, the plugin is a no-op.
+
+> **Tip:** You can add these environment variables to your shell profile (for example, `~/.zshrc` or `~/.bashrc`) so they persist across sessions.
+
+## Start OpenCode
+
+Start OpenCode as normal:
+
+```bash
+opencode
+```
+
+The plugin initializes automatically and starts capturing LLM calls, tool executions, and completed prompt traces once OpenCode is running.
+
+## Verify traces and generations
+
+After running a few prompts through OpenCode:
+
+1. Go to the [LLM analytics](https://us.posthog.com/llm-analytics) tab in PostHog.
+2. You should see traces and generations appearing within a few minutes.
+
+## Configuration options
+
+All configuration is done via environment variables:
+
+| Variable | Default | Description |
+|---|---|---|
+| `POSTHOG_API_KEY` | _(required)_ | Your PostHog project API key |
+| `POSTHOG_HOST` | `https://us.i.posthog.com` | PostHog instance URL |
+| `POSTHOG_PRIVACY_MODE` | `false` | Redact all LLM input/output content when `true` |
+| `POSTHOG_ENABLED` | `true` | Set `false` to disable |
+| `POSTHOG_DISTINCT_ID` | machine hostname | The `distinct_id` for all events |
+| `POSTHOG_PROJECT_NAME` | cwd basename | Project name in all events |
+| `POSTHOG_TAGS` | _(none)_ | Custom tags: `key1:val1,key2:val2` |
+| `POSTHOG_MAX_ATTRIBUTE_LENGTH` | `12000` | Max length for serialized tool input/output |
+
+### What gets captured
+
+The plugin captures three types of events:
+
+- **`$ai_generation`**: Every LLM call, including model, provider, token usage, cost, stop reason, and message content in [OpenAI chat format](/docs/llm-analytics/generations).
+- **`$ai_span`**: Each tool execution, including tool name, duration, input and output state, and any error information ([learn more](/docs/llm-analytics/spans)).
+- **`$ai_trace`**: Completed user prompts with total latency, accumulated token counts, and final input and output state ([learn more](/docs/llm-analytics/traces)).
+
+### Privacy mode
+
+When `POSTHOG_PRIVACY_MODE=true`, content fields such as `$ai_input`, `$ai_output_choices`, `$ai_input_state`, and `$ai_output_state` are set to `null`. Token counts, costs, latency, and model metadata are still captured.
+
+Sensitive keys in tool inputs and outputs, including `api_key`, `token`, `secret`, `password`, `authorization`, `credential`, and `private_key`, are automatically redacted regardless of whether privacy mode is enabled.
+
+## Next steps
+
+Now that you're capturing AI conversations, continue with the resources below to learn what else LLM analytics enables within the PostHog platform.
+
+| Resource | Description |
+|----------|-------------|
+| [Basics](/docs/llm-analytics/basics) | Learn the basics of how LLM calls become events in PostHog. |
+| [Generations](/docs/llm-analytics/generations) | Read about the `$ai_generation` event and its properties. |
+| [Traces](/docs/llm-analytics/traces) | Explore the trace hierarchy and how to use it to debug LLM calls. |
+| [Spans](/docs/llm-analytics/spans) | Review spans and their role in representing individual operations. |
+| [Analyze LLM performance](/docs/llm-analytics/dashboard) | Learn how to create dashboards to analyze LLM performance. |

src/components/OSIcons/Icons.tsx

@@ -452,6 +452,18 @@ export const IconOpenClaw = (props: IconProps) => (
     </BaseIcon>
 )
 
+export const IconOpenCode = (props: IconProps) => (
+    <BaseIcon viewBox="0 0 300 300" width="100%" height="100%" {...props}>
+        <path
+            fillRule="evenodd"
+            clipRule="evenodd"
+            d="M210 60H90V240H210V60ZM270 300H30V0H270V300Z"
+            className="fill-[#211E1E] dark:fill-[#F1ECEC]"
+        />
+        <path d="M210 240H90V120H210V240Z" className="fill-[#CFCECD] dark:fill-[#4B4646]" />
+    </BaseIcon>
+)
+
 export const IconOpenAI = (props: IconProps) => (
     <BaseIcon viewBox="0 0 24 24" width="100%" height="100%" {...props}>
         <path d="M9.67 9.215V7.332c0-.159.06-.278.2-.357l3.785-2.18c.516-.297 1.13-.436 1.764-.436 2.379 0 3.885 1.843 3.885 3.806 0 .138 0 .297-.02.455L15.36 6.321a.664.664 0 0 0-.714 0L9.671 9.215Zm8.841 7.334v-4.5a.663.663 0 0 0-.357-.614L13.18 8.54l1.626-.932a.36.36 0 0 1 .396 0l3.786 2.18c1.09.635 1.824 1.983 1.824 3.291 0 1.506-.892 2.894-2.3 3.469Zm-10.01-3.964-1.625-.952c-.139-.079-.198-.198-.198-.356V6.916c0-2.121 1.625-3.727 3.826-3.727a3.71 3.71 0 0 1 2.26.773l-3.906 2.26a.663.663 0 0 0-.356.615v5.748ZM12 14.606l-2.33-1.308v-2.775L12 9.215l2.329 1.308v2.775L12 14.607Zm1.496 6.026a3.71 3.71 0 0 1-2.26-.773l3.906-2.26a.663.663 0 0 0 .356-.614v-5.748l1.646.951c.138.08.198.198.198.357v4.36c0 2.121-1.645 3.727-3.845 3.727ZM8.8 16.212l-3.786-2.18c-1.09-.635-1.824-1.982-1.824-3.29 0-1.527.912-2.894 2.32-3.47v4.52c0 .277.118.476.356.614l4.955 2.874-1.625.932a.36.36 0 0 1-.396 0Zm-.218 3.25c-2.24 0-3.885-1.684-3.885-3.765 0-.159.02-.317.04-.476l3.904 2.26a.664.664 0 0 0 .714 0l4.975-2.874v1.883c0 .158-.06.277-.198.357l-3.786 2.18c-.516.297-1.13.436-1.764.436Zm4.915 2.36c2.399 0 4.4-1.705 4.857-3.965C20.573 17.282 22 15.201 22 13.08a5.013 5.013 0 0 0-1.665-3.706c.1-.417.159-.833.159-1.25 0-2.834-2.3-4.955-4.956-4.955-.535 0-1.05.08-1.566.258A4.968 4.968 0 0 0 10.504 2a4.956 4.956 0 0 0-4.857 3.964C3.427 6.54 2 8.62 2 10.741c0 1.388.595 2.736 1.665 3.707a5.39 5.39 0 0 0-.159 1.249c0 2.834 2.3 4.955 4.956 4.955.535 0 1.05-.08 1.566-.258a4.967 4.967 0 0 0 3.468 1.428Z" />

src/navs/index.js

@@ -5703,6 +5703,11 @@ export const docsMenu = {
                             url: '/docs/llm-analytics/installation/pi',
                             icon: 'IconCode',
                         },
+                        {
+                            name: 'OpenCode',
+                            url: '/docs/llm-analytics/installation/opencode',
+                            icon: 'IconOpenCode',
+                        },
                         {
                             name: 'Claude Code',
                             url: '/docs/llm-analytics/installation/claude-code',