feat(opencode): add changed-files tree with change indicators (#815)

* feat(opencode): add changed-files tree with change indicators

* feat(opencode): address changed-files review feedback

---------

Co-authored-by: Affaan Mustafa <me@affaanmustafa.com>

.opencode/tools/changed-files.ts

@@ -0,0 +1,81 @@
+import { tool } from "@opencode-ai/plugin/tool"
+import {
+  buildTree,
+  getChangedPaths,
+  hasChanges,
+  type ChangeType,
+  type TreeNode,
+} from "../plugins/lib/changed-files-store.js"
+
+const INDICATORS: Record<ChangeType, string> = {
+  added: "+",
+  modified: "~",
+  deleted: "-",
+}
+
+function renderTree(nodes: TreeNode[], indent: string): string {
+  const lines: string[] = []
+  for (const node of nodes) {
+    const indicator = node.changeType ? ` (${INDICATORS[node.changeType]})` : ""
+    const name = node.changeType ? `${node.name}${indicator}` : `${node.name}/`
+    lines.push(`${indent}${name}`)
+    if (node.children.length > 0) {
+      lines.push(renderTree(node.children, `${indent}  `))
+    }
+  }
+  return lines.join("\n")
+}
+
+export default tool({
+  description:
+    "List files changed by agents in this session as a navigable tree. Shows added (+), modified (~), and deleted (-) indicators. Use filter to show only specific change types. Returns paths for git diff.",
+  args: {
+    filter: tool.schema
+      .enum(["all", "added", "modified", "deleted"])
+      .optional()
+      .describe("Filter by change type (default: all)"),
+    format: tool.schema
+      .enum(["tree", "json"])
+      .optional()
+      .describe("Output format: tree for terminal display, json for structured data (default: tree)"),
+  },
+  async execute(args, context) {
+    const filter = args.filter === "all" || !args.filter ? undefined : (args.filter as ChangeType)
+    const format = args.format ?? "tree"
+
+    if (!hasChanges()) {
+      return JSON.stringify({ changed: false, message: "No files changed in this session" })
+    }
+
+    const paths = getChangedPaths(filter)
+
+    if (format === "json") {
+      return JSON.stringify(
+        {
+          changed: true,
+          filter: filter ?? "all",
+          files: paths.map((p) => ({ path: p.path, changeType: p.changeType })),
+          diffCommands: paths
+            .filter((p) => p.changeType !== "added")
+            .map((p) => `git diff ${p.path}`),
+        },
+        null,
+        2
+      )
+    }
+
+    const tree = buildTree(filter)
+    const treeStr = renderTree(tree, "")
+    const diffHint = paths
+      .filter((p) => p.changeType !== "added")
+      .slice(0, 5)
+      .map((p) => `  git diff ${p.path}`)
+      .join("\n")
+
+    let output = `Changed files (${paths.length}):\n\n${treeStr}`
+    if (diffHint) {
+      output += `\n\nTo view diff for a file:\n${diffHint}`
+    }
+    return output
+  },
+})

.opencode/tools/index.ts

@@ -11,3 +11,4 @@ export { default as securityAudit } from "./security-audit.js"
 export { default as formatCode } from "./format-code.js"
 export { default as lintCheck } from "./lint-check.js"
 export { default as gitSummary } from "./git-summary.js"
+export { default as changedFiles } from "./changed-files.js"