diff --git a/packages/opencode/src/session/compaction.ts b/packages/opencode/src/session/compaction.ts
index ae69221288f8..b2c0fb607ec6 100644
--- a/packages/opencode/src/session/compaction.ts
+++ b/packages/opencode/src/session/compaction.ts
@@ -110,7 +110,7 @@ export namespace SessionCompaction {
       agent: "compaction",
       summary: true,
       path: {
-        cwd: Instance.directory,
+        cwd: Session.directory.get(),
         root: Instance.worktree,
       },
       cost: 0,
diff --git a/packages/opencode/src/session/index.ts b/packages/opencode/src/session/index.ts
index 3fcdab5238c3..f249b535588e 100644
--- a/packages/opencode/src/session/index.ts
+++ b/packages/opencode/src/session/index.ts
@@ -23,9 +23,22 @@ import type { Provider } from "@/provider/provider"
 import { PermissionNext } from "@/permission/next"
 import { Global } from "@/global"
 
+// Current working directory for the active session.
+let _sessionDirectory: string | undefined
+
 export namespace Session {
   const log = Log.create({ service: "session" })
 
+  /** Get/set the current session's working directory. Falls back to Instance.directory if not set. */
+  export const directory = {
+    get() {
+      return _sessionDirectory ?? Instance.directory
+    },
+    set(value: string | undefined) {
+      _sessionDirectory = value
+    },
+  }
+
   const parentTitlePrefix = "New session - "
   const childTitlePrefix = "Child session - "
 
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index f4793d1a7987..1c7558e0f626 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -267,6 +267,10 @@ export namespace SessionPrompt {
 
     let step = 0
     const session = await Session.get(sessionID)
+    
+    // Set the working directory for this session (enables session-specific directories)
+    Session.directory.set(session.directory)
+    
     while (true) {
       SessionStatus.set(sessionID, { type: "busy" })
       log.info("loop", { step, sessionID })
@@ -325,7 +329,7 @@ export namespace SessionPrompt {
           mode: task.agent,
           agent: task.agent,
           path: {
-            cwd: Instance.directory,
+            cwd: Session.directory.get(),
             root: Instance.worktree,
           },
           cost: 0,
@@ -525,7 +529,7 @@ export namespace SessionPrompt {
           mode: agent.name,
           agent: agent.name,
           path: {
-            cwd: Instance.directory,
+            cwd: Session.directory.get(),
             root: Instance.worktree,
           },
           cost: 0,
@@ -1350,6 +1354,10 @@ NOTE: At any point in time through this workflow you should feel free to ask the
     using _ = defer(() => cancel(input.sessionID))
 
     const session = await Session.get(input.sessionID)
+    
+    // Set the working directory for this session (enables session-specific directories)
+    Session.directory.set(session.directory)
+    
     if (session.revert) {
       SessionRevert.cleanup(session)
     }
@@ -1478,7 +1486,7 @@ NOTE: At any point in time through this workflow you should feel free to ask the
     const args = matchingInvocation?.args
 
     const proc = spawn(shell, args, {
-      cwd: Instance.directory,
+      cwd: Session.directory.get(),
       detached: process.platform !== "win32",
       stdio: ["ignore", "pipe", "pipe"],
       env: {
diff --git a/packages/opencode/src/session/system.ts b/packages/opencode/src/session/system.ts
index fff90808864b..99ef4aba5715 100644
--- a/packages/opencode/src/session/system.ts
+++ b/packages/opencode/src/session/system.ts
@@ -4,6 +4,7 @@ import { Filesystem } from "../util/filesystem"
 import { Config } from "../config/config"
 
 import { Instance } from "../project/instance"
+import { Session } from "./index"
 import path from "path"
 import os from "os"
 
@@ -43,7 +44,7 @@ export namespace SystemPrompt {
       [
         `Here is some useful information about the environment you are running in:`,
         `<env>`,
-        `  Working directory: ${Instance.directory}`,
+        `  Working directory: ${Session.directory.get()}`,
         `  Is directory a git repo: ${project.vcs === "git" ? "yes" : "no"}`,
         `  Platform: ${process.platform}`,
         `  Today's date: ${new Date().toDateString()}`,
@@ -52,7 +53,7 @@ export namespace SystemPrompt {
         `  ${
           project.vcs === "git" && false
             ? await Ripgrep.tree({
-                cwd: Instance.directory,
+                cwd: Session.directory.get(),
                 limit: 200,
               })
             : ""
diff --git a/packages/opencode/src/tool/apply_patch.ts b/packages/opencode/src/tool/apply_patch.ts
index d070eaefa978..f64f0dbbcda1 100644
--- a/packages/opencode/src/tool/apply_patch.ts
+++ b/packages/opencode/src/tool/apply_patch.ts
@@ -6,6 +6,7 @@ import { FileTime } from "../file/time"
 import { Bus } from "../bus"
 import { FileWatcher } from "../file/watcher"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import { Patch } from "../patch"
 import { createTwoFilesPatch, diffLines } from "diff"
 import { assertExternalDirectory } from "./external-directory"
@@ -57,7 +58,7 @@ export const ApplyPatchTool = Tool.define("apply_patch", {
     let totalDiff = ""
 
     for (const hunk of hunks) {
-      const filePath = path.resolve(Instance.directory, hunk.path)
+      const filePath = path.resolve(Session.directory.get(), hunk.path)
       await assertExternalDirectory(ctx, filePath)
 
       switch (hunk.type) {
@@ -117,7 +118,7 @@ export const ApplyPatchTool = Tool.define("apply_patch", {
             if (change.removed) deletions += change.count || 0
           }
 
-          const movePath = hunk.move_path ? path.resolve(Instance.directory, hunk.move_path) : undefined
+          const movePath = hunk.move_path ? path.resolve(Session.directory.get(), hunk.move_path) : undefined
           await assertExternalDirectory(ctx, movePath)
 
           fileChanges.push({
diff --git a/packages/opencode/src/tool/bash.ts b/packages/opencode/src/tool/bash.ts
index f3a1b04d4310..e49c2d00c41d 100644
--- a/packages/opencode/src/tool/bash.ts
+++ b/packages/opencode/src/tool/bash.ts
@@ -5,6 +5,7 @@ import path from "path"
 import DESCRIPTION from "./bash.txt"
 import { Log } from "../util/log"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import { lazy } from "@/util/lazy"
 import { Language } from "web-tree-sitter"
 
@@ -56,7 +57,7 @@ export const BashTool = Tool.define("bash", async () => {
   log.info("bash tool using shell", { shell })
 
   return {
-    description: DESCRIPTION.replaceAll("${directory}", Instance.directory)
+    description: DESCRIPTION.replaceAll("${directory}", Session.directory.get())
       .replaceAll("${maxLines}", String(Truncate.MAX_LINES))
       .replaceAll("${maxBytes}", String(Truncate.MAX_BYTES)),
     parameters: z.object({
@@ -65,7 +66,7 @@ export const BashTool = Tool.define("bash", async () => {
       workdir: z
         .string()
         .describe(
-          `The working directory to run the command in. Defaults to ${Instance.directory}. Use this instead of 'cd' commands.`,
+          `The working directory to run the command in. Defaults to ${Session.directory.get()}. Use this instead of 'cd' commands.`,
         )
         .optional(),
       description: z
@@ -75,7 +76,7 @@ export const BashTool = Tool.define("bash", async () => {
         ),
     }),
     async execute(params, ctx) {
-      const cwd = params.workdir || Instance.directory
+      const cwd = params.workdir || Session.directory.get()
       if (params.timeout !== undefined && params.timeout < 0) {
         throw new Error(`Invalid timeout value: ${params.timeout}. Timeout must be a positive number.`)
       }
diff --git a/packages/opencode/src/tool/edit.ts b/packages/opencode/src/tool/edit.ts
index 26db5b228362..7715b1a404b1 100644
--- a/packages/opencode/src/tool/edit.ts
+++ b/packages/opencode/src/tool/edit.ts
@@ -14,6 +14,7 @@ import { Bus } from "../bus"
 import { FileTime } from "../file/time"
 import { Filesystem } from "../util/filesystem"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import { Snapshot } from "@/snapshot"
 import { assertExternalDirectory } from "./external-directory"
 
@@ -40,7 +41,7 @@ export const EditTool = Tool.define("edit", {
       throw new Error("oldString and newString must be different")
     }
 
-    const filePath = path.isAbsolute(params.filePath) ? params.filePath : path.join(Instance.directory, params.filePath)
+    const filePath = path.isAbsolute(params.filePath) ? params.filePath : path.join(Session.directory.get(), params.filePath)
     await assertExternalDirectory(ctx, filePath)
 
     let diff = ""
diff --git a/packages/opencode/src/tool/glob.ts b/packages/opencode/src/tool/glob.ts
index dda57f6ee1b9..b831f8eea151 100644
--- a/packages/opencode/src/tool/glob.ts
+++ b/packages/opencode/src/tool/glob.ts
@@ -4,6 +4,7 @@ import { Tool } from "./tool"
 import DESCRIPTION from "./glob.txt"
 import { Ripgrep } from "../file/ripgrep"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import { assertExternalDirectory } from "./external-directory"
 
 export const GlobTool = Tool.define("glob", {
@@ -28,8 +29,8 @@ export const GlobTool = Tool.define("glob", {
       },
     })
 
-    let search = params.path ?? Instance.directory
-    search = path.isAbsolute(search) ? search : path.resolve(Instance.directory, search)
+    let search = params.path ?? Session.directory.get()
+    search = path.isAbsolute(search) ? search : path.resolve(Session.directory.get(), search)
     await assertExternalDirectory(ctx, search, { kind: "directory" })
 
     const limit = 100
diff --git a/packages/opencode/src/tool/grep.ts b/packages/opencode/src/tool/grep.ts
index 097dedf4aafc..7ca7e3262e9a 100644
--- a/packages/opencode/src/tool/grep.ts
+++ b/packages/opencode/src/tool/grep.ts
@@ -4,6 +4,7 @@ import { Ripgrep } from "../file/ripgrep"
 
 import DESCRIPTION from "./grep.txt"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import path from "path"
 import { assertExternalDirectory } from "./external-directory"
 
@@ -32,8 +33,8 @@ export const GrepTool = Tool.define("grep", {
       },
     })
 
-    let searchPath = params.path ?? Instance.directory
-    searchPath = path.isAbsolute(searchPath) ? searchPath : path.resolve(Instance.directory, searchPath)
+    let searchPath = params.path ?? Session.directory.get()
+    searchPath = path.isAbsolute(searchPath) ? searchPath : path.resolve(Session.directory.get(), searchPath)
     await assertExternalDirectory(ctx, searchPath, { kind: "directory" })
 
     const rgPath = await Ripgrep.filepath()
diff --git a/packages/opencode/src/tool/ls.ts b/packages/opencode/src/tool/ls.ts
index cc3d750078f1..800e4126d737 100644
--- a/packages/opencode/src/tool/ls.ts
+++ b/packages/opencode/src/tool/ls.ts
@@ -3,6 +3,7 @@ import { Tool } from "./tool"
 import * as path from "path"
 import DESCRIPTION from "./ls.txt"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import { Ripgrep } from "../file/ripgrep"
 import { assertExternalDirectory } from "./external-directory"
 
@@ -42,7 +43,7 @@ export const ListTool = Tool.define("list", {
     ignore: z.array(z.string()).describe("List of glob patterns to ignore").optional(),
   }),
   async execute(params, ctx) {
-    const searchPath = path.resolve(Instance.directory, params.path || ".")
+    const searchPath = path.resolve(Session.directory.get(), params.path || ".")
     await assertExternalDirectory(ctx, searchPath, { kind: "directory" })
 
     await ctx.ask({
diff --git a/packages/opencode/src/tool/lsp.ts b/packages/opencode/src/tool/lsp.ts
index ca352280b2a9..77eb2b385a87 100644
--- a/packages/opencode/src/tool/lsp.ts
+++ b/packages/opencode/src/tool/lsp.ts
@@ -4,6 +4,7 @@ import path from "path"
 import { LSP } from "../lsp"
 import DESCRIPTION from "./lsp.txt"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import { pathToFileURL } from "url"
 import { assertExternalDirectory } from "./external-directory"
 
@@ -28,7 +29,7 @@ export const LspTool = Tool.define("lsp", {
     character: z.number().int().min(1).describe("The character offset (1-based, as shown in editors)"),
   }),
   execute: async (args, ctx) => {
-    const file = path.isAbsolute(args.filePath) ? args.filePath : path.join(Instance.directory, args.filePath)
+    const file = path.isAbsolute(args.filePath) ? args.filePath : path.join(Session.directory.get(), args.filePath)
     await assertExternalDirectory(ctx, file)
 
     await ctx.ask({
diff --git a/packages/opencode/src/tool/write.ts b/packages/opencode/src/tool/write.ts
index cfcf6a0dab7e..3542fd6ba4b8 100644
--- a/packages/opencode/src/tool/write.ts
+++ b/packages/opencode/src/tool/write.ts
@@ -9,6 +9,7 @@ import { File } from "../file"
 import { FileTime } from "../file/time"
 import { Filesystem } from "../util/filesystem"
 import { Instance } from "../project/instance"
+import { Session } from "../session"
 import { trimDiff } from "./edit"
 import { assertExternalDirectory } from "./external-directory"
 
@@ -22,7 +23,7 @@ export const WriteTool = Tool.define("write", {
     filePath: z.string().describe("The absolute path to the file to write (must be absolute, not relative)"),
   }),
   async execute(params, ctx) {
-    const filepath = path.isAbsolute(params.filePath) ? params.filePath : path.join(Instance.directory, params.filePath)
+    const filepath = path.isAbsolute(params.filePath) ? params.filePath : path.join(Session.directory.get(), params.filePath)
     await assertExternalDirectory(ctx, filepath)
 
     const file = Bun.file(filepath)
diff --git a/packages/opencode/test/session/directory.test.ts b/packages/opencode/test/session/directory.test.ts
new file mode 100644
index 000000000000..daa3db1bfa27
--- /dev/null
+++ b/packages/opencode/test/session/directory.test.ts
@@ -0,0 +1,23 @@
+import { describe, expect, test, beforeEach } from "bun:test"
+import { Session } from "../../src/session"
+
+describe("Session.directory", () => {
+  beforeEach(() => {
+    // Reset to undefined before each test
+    Session.directory.set(undefined)
+  })
+
+  test("should return custom directory when set", () => {
+    const customDir = "/custom/worktree/path"
+    Session.directory.set(customDir)
+    expect(Session.directory.get()).toBe(customDir)
+  })
+
+  test("should update when set multiple times", () => {
+    Session.directory.set("/first/path")
+    expect(Session.directory.get()).toBe("/first/path")
+
+    Session.directory.set("/second/path")
+    expect(Session.directory.get()).toBe("/second/path")
+  })
+})