chore: add missing altimate_change markers for upstream merge safety (#322)

Wraps custom code in upstream-shared files with `altimate_change` markers
so the marker guard CI catches them during future upstream merges:

- `skill/skill.ts`: `gray-matter` import, `OPENCODE_BUILTIN_SKILLS` global,
  builtin skill loading logic, `builtin:` protocol in `fmt()`
- `tool/bash.ts`: `ALTIMATE_BIN_DIR` PATH prepend logic
- `tool/skill.ts`: `isBuiltin` branch for embedded skill file resolution

Closes #321

Author: anandgupta42

packages/opencode/src/skill/skill.ts

@@ -1,7 +1,9 @@
 import z from "zod"
 import path from "path"
 import os from "os"
+// altimate_change start — gray-matter for parsing embedded builtin skill frontmatter
 import matter from "gray-matter"
+// altimate_change end
 import { Config } from "../config/config"
 import { Instance } from "../project/instance"
 import { NamedError } from "@opencode-ai/util/error"
@@ -18,12 +20,11 @@ import { pathToFileURL } from "url"
 import type { Agent } from "@/agent/agent"
 import { PermissionNext } from "@/permission/next"
 
-// Builtin skills embedded at build time — available in ALL distribution channels
-// (npm, Homebrew, AUR, Docker) without relying on postinstall filesystem copies.
-// Falls back to filesystem scan in dev mode when the global is undefined.
+// altimate_change start — builtin skills embedded at build time for all distribution channels
 declare const OPENCODE_BUILTIN_SKILLS:
   | { name: string; content: string }[]
   | undefined
+// altimate_change end
 
 export namespace Skill {
   const log = Log.create({ service: "skill" })
@@ -112,8 +113,7 @@ export namespace Skill {
         })
     }
 
-    // Load builtin skills — prefer filesystem (supports @references), fall back
-    // to binary-embedded data (works without postinstall for Homebrew/AUR/Docker).
+    // altimate_change start — load builtin skills from filesystem or binary-embedded data
     if (!Flag.OPENCODE_DISABLE_EXTERNAL_SKILLS) {
       let loadedFromFs = false
 
@@ -155,6 +155,7 @@ export namespace Skill {
         log.info("loaded embedded builtin skills", { count: OPENCODE_BUILTIN_SKILLS.length })
       }
     }
+    // altimate_change end
 
     // Scan external skill directories (.claude/skills/, .agents/skills/, etc.)
     // Load global (home) first, then project-level (so project-level overwrites)
@@ -259,7 +260,9 @@ export namespace Skill {
           `  <skill>`,
           `    <name>${skill.name}</name>`,
           `    <description>${skill.description}</description>`,
+          // altimate_change start — handle builtin: protocol for embedded skills
           `    <location>${skill.location.startsWith("builtin:") ? skill.location : pathToFileURL(skill.location).href}</location>`,
+          // altimate_change end
           `  </skill>`,
         ]),
         "</available_skills>",

packages/opencode/src/tool/bash.ts

@@ -165,8 +165,7 @@ export const BashTool = Tool.define("bash", async () => {
         { env: {} },
       )
 
-      // Merge process.env + shell plugin env, then prepend bundled tools dir.
-      // shellEnv.env may contain PATH additions from user's shell profile.
+      // altimate_change start — prepend bundled tools dir (ALTIMATE_BIN_DIR) to PATH
       const mergedEnv: Record<string, string | undefined> = { ...process.env, ...shellEnv.env }
       const binDir = process.env.ALTIMATE_BIN_DIR
       if (binDir) {
@@ -177,6 +176,7 @@ export const BashTool = Tool.define("bash", async () => {
           mergedEnv.PATH = basePath ? `${binDir}${sep}${basePath}` : binDir
         }
       }
+      // altimate_change end
 
       const proc = spawn(params.command, {
         shell,

packages/opencode/src/tool/skill.ts

@@ -112,6 +112,7 @@ export const SkillTool = Tool.define("skill", async (ctx) => {
         metadata: {},
       })
 
+      // altimate_change start — handle builtin: skills that have no filesystem directory
       const isBuiltin = skill.location.startsWith("builtin:")
       const dir = isBuiltin ? "" : path.dirname(skill.location)
       const base = isBuiltin ? skill.location : pathToFileURL(dir).href
@@ -137,6 +138,7 @@ export const SkillTool = Tool.define("skill", async (ctx) => {
             }
             return arr
           }).then((f) => f.map((file) => `<file>${file}</file>`).join("\n"))
+      // altimate_change end
 
       // altimate_change start — telemetry instrumentation for skill loading
       try {