docs(implementation): add /goal implementation doc with community tweet tips

Embeds two X.com screenshots (Alex Finn, Meta Alchemist) with verbatim
tweet text and source URLs. Covers two patterns: asking the agent to
propose its own /goals, and asking it to draft a /goal prompt from
session + repo context.

Co-Authored-By: Claude <noreply@anthropic.com>

implementation/claude-goal-implementation.md

@@ -0,0 +1,86 @@
+# Goal Implementation
+
+![Last Updated](https://img.shields.io/badge/Last_Updated-May_13%2C_2026-white?style=flat&labelColor=555)
+
+<table width="100%">
+<tr>
+<td><a href="../">← Back to Claude Code Best Practice</a></td>
+<td align="right"><img src="../!/claude-jumping.svg" alt="Claude" width="60" /></td>
+</tr>
+</table>
+
+---
+
+<a href="#goal-tips-from-the-community"><img src="../!/tags/implemented-hd.svg" alt="Implemented"></a>
+
+`/goal` keeps your agent working across turns until a condition is satisfied — Claude Code, Codex, and Hermes Agent all support it. The community is converging on a few high-leverage prompting tricks that pair well with it.
+
+---
+
+## Goal Tips from the Community
+
+### 1. Ask the agent to propose its own goals
+
+<p align="center">
+  <img src="assets/impl-goal-claude.png" alt="Alex Finn tweet — /goal is the most underrated AI feature of 2026" width="50%">
+</p>
+
+> It's official. Claude Code just released /goal
+>
+> The single most underrated AI feature of 2026
+>
+> Now Claude Code, Codex, and Hermes agent have it
+>
+> It allows your agent to complete long running tasks, sometimes for days
+>
+> EVERYONE should be immediately running this prompt:
+>
+> 'Based on what you know about me, my goals, ambitions, and what we've built together already, what are the 3 /goals we can run right now that would run for long time periods and produce the best results?'
+>
+> Choose one, then ask for it to build you a prompt
+>
+> You should get a few options for super powerful goal prompts that will have your agent of choice complete long running tasks that will deliver your mind blowing results.
+>
+> Carve out 15 minutes tonight to do this. Thank me later.
+
+**Source:** [Alex Finn (@AlexFinn) on X](https://x.com/AlexFinn/status/2053976411296452887)
+
+---
+
+### 2. Let the agent draft the /goal prompt for you
+
+<p align="center">
+  <img src="assets/impl-goal-codex.png" alt="Meta Alchemist tweet — /goal trick for Codex" width="50%">
+</p>
+
+> wanna know the best /goal trick for Codex?
+>
+> just tell your Codex:
+>
+> "read this session and repo, analyze deeply the exact intent and goals we are looking to achieve here then write me the /goal prompt for this.
+>
+> make sure to dig into history & docs we have to be 100% clear"
+>
+> also you can add:
+>
+> "if you are not sure about certain parts or wanna ask me a few questions to clarify certain goals further don't hesitate"
+>
+> then just copy paste what Codex gives you change the initial part to /goal
+>
+> and it will do exactly what you wanted to do in that session / repo, nonstop until it gets to completion.
+
+**Source:** [Meta Alchemist (@meta_alchemist) on X](https://x.com/meta_alchemist/status/2054214497443995694)
+
+---
+
+## ![How to Use](../!/tags/how-to-use.svg)
+
+```bash
+$ claude
+> /goal <condition>
+> /goal clear
+```
+
+`/goal <condition>` keeps Claude working across turns until a Haiku-evaluated condition holds. It is complementary to `/loop` (time-driven) and auto mode (per-tool). Requires Claude Code v2.1.139+.
+
+See the [official docs](https://code.claude.com/docs/en/goal) for full behavior.