From a8c18dba8205d7707a46ec0859db672370be8963 Mon Sep 17 00:00:00 2001
From: adamelmore <2363879+adamdottv@users.noreply.github.com>
Date: Mon, 26 Jan 2026 19:57:34 -0600
Subject: [PATCH] fix(core): expose Instance.directory to custom tools

---
 packages/opencode/src/tool/read.ts             |  2 +-
 packages/opencode/src/tool/registry.ts         |  5 +++--
 packages/plugin/src/tool.ts                    |  5 +++++
 packages/web/src/content/docs/custom-tools.mdx | 10 ++++++----
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/packages/opencode/src/tool/read.ts b/packages/opencode/src/tool/read.ts
index 93c1b751f..746e0b173 100644
--- a/packages/opencode/src/tool/read.ts
+++ b/packages/opencode/src/tool/read.ts
@@ -24,7 +24,7 @@ export const ReadTool = Tool.define("read", {
   async execute(params, ctx) {
     let filepath = params.filePath
     if (!path.isAbsolute(filepath)) {
-      filepath = path.join(Instance.directory, filepath)
+      filepath = path.resolve(Instance.directory, filepath)
     }
     const title = path.relative(Instance.worktree, filepath)
 
diff --git a/packages/opencode/src/tool/registry.ts b/packages/opencode/src/tool/registry.ts
index faa5f72bc..2c862dfd8 100644
--- a/packages/opencode/src/tool/registry.ts
+++ b/packages/opencode/src/tool/registry.ts
@@ -16,7 +16,7 @@ import { Tool } from "./tool"
 import { Instance } from "../project/instance"
 import { Config } from "../config/config"
 import path from "path"
-import { type ToolDefinition } from "@opencode-ai/plugin"
+import { type ToolContext as PluginToolContext, type ToolDefinition } from "@opencode-ai/plugin"
 import z from "zod"
 import { Plugin } from "../plugin"
 import { WebSearchTool } from "./websearch"
@@ -67,7 +67,8 @@ export namespace ToolRegistry {
         parameters: z.object(def.args),
         description: def.description,
         execute: async (args, ctx) => {
-          const result = await def.execute(args as any, ctx)
+          const pluginCtx = { ...ctx, directory: Instance.directory } as unknown as PluginToolContext
+          const result = await def.execute(args as any, pluginCtx)
           const out = await Truncate.output(result, {}, initCtx?.agent)
           return {
             title: "",
diff --git a/packages/plugin/src/tool.ts b/packages/plugin/src/tool.ts
index f759c07d2..6b4f7f1d1 100644
--- a/packages/plugin/src/tool.ts
+++ b/packages/plugin/src/tool.ts
@@ -4,6 +4,11 @@ export type ToolContext = {
   sessionID: string
   messageID: string
   agent: string
+  /**
+   * Current project directory for this session.
+   * Prefer this over process.cwd() when resolving relative paths.
+   */
+  directory: string
   abort: AbortSignal
   metadata(input: { title?: string; metadata?: { [key: string]: any } }): void
   ask(input: AskInput): Promise<void>
diff --git a/packages/web/src/content/docs/custom-tools.mdx b/packages/web/src/content/docs/custom-tools.mdx
index e089a035b..ef93a64e2 100644
--- a/packages/web/src/content/docs/custom-tools.mdx
+++ b/packages/web/src/content/docs/custom-tools.mdx
@@ -120,8 +120,8 @@ export default tool({
   args: {},
   async execute(args, context) {
     // Access context information
-    const { agent, sessionID, messageID } = context
-    return `Agent: ${agent}, Session: ${sessionID}, Message: ${messageID}`
+    const { agent, sessionID, messageID, directory } = context
+    return `Agent: ${agent}, Session: ${sessionID}, Message: ${messageID}, Directory: ${directory}`
   },
 })
 ```
@@ -148,6 +148,7 @@ Then create the tool definition that invokes it:
 
 ```ts title=".opencode/tools/python-add.ts" {10}
 import { tool } from "@opencode-ai/plugin"
+import path from "path"
 
 export default tool({
   description: "Add two numbers using Python",
@@ -155,8 +156,9 @@ export default tool({
     a: tool.schema.number().describe("First number"),
     b: tool.schema.number().describe("Second number"),
   },
-  async execute(args) {
-    const result = await Bun.$`python3 .opencode/tools/add.py ${args.a} ${args.b}`.text()
+  async execute(args, context) {
+    const script = path.join(context.directory, ".opencode/tools/add.py")
+    const result = await Bun.$`python3 ${script} ${args.a} ${args.b}`.text()
     return result.trim()
   },
 })