feat(tool): expose session context to child processes via environment variables

packages/opencode/src/session/prompt.ts

@@ -1484,6 +1484,8 @@ NOTE: At any point in time through this workflow you should feel free to ask the
       env: {
         ...process.env,
         TERM: "dumb",
+        OPENCODE_SESSION_ID: input.sessionID,
+        OPENCODE_SESSION_TITLE: session.title,
       },
     })
 

packages/opencode/src/tool/bash.ts

@@ -16,6 +16,7 @@ import { Shell } from "@/shell/shell"
 
 import { BashArity } from "@/permission/arity"
 import { Truncate } from "./truncation"
+import { Session } from "@/session"
 
 const MAX_METADATA_LENGTH = 30_000
 const DEFAULT_TIMEOUT = Flag.OPENCODE_EXPERIMENTAL_BASH_DEFAULT_TIMEOUT_MS || 2 * 60 * 1000
@@ -154,11 +155,20 @@ export const BashTool = Tool.define("bash", async () => {
         })
       }
 
+      const session = await (async () => {
+        try {
+          return await Session.get(ctx.sessionID)
+        } catch {
+          return undefined
+        }
+      })()
       const proc = spawn(params.command, {
         shell,
         cwd,
         env: {
           ...process.env,
+          OPENCODE_SESSION_ID: ctx.sessionID,
+          ...(session?.title && { OPENCODE_SESSION_TITLE: session.title }),
         },
         stdio: ["ignore", "pipe", "pipe"],
         detached: process.platform !== "win32",

packages/opencode/test/tool/bash.test.ts

@@ -5,6 +5,7 @@ import { Instance } from "../../src/project/instance"
 import { tmpdir } from "../fixture/fixture"
 import type { PermissionNext } from "../../src/permission/next"
 import { Truncate } from "../../src/tool/truncation"
+import { Session } from "../../src/session"
 
 const ctx = {
   sessionID: "test",
@@ -36,6 +37,54 @@ describe("tool.bash", () => {
       },
     })
   })
+
+  test("exposes OPENCODE_SESSION_ID environment variable", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const bash = await BashTool.init()
+        const sessionID = "session_abc123"
+        const testCtx = {
+          ...ctx,
+          sessionID,
+        }
+        const result = await bash.execute(
+          {
+            command: process.platform === "win32" ? "echo %OPENCODE_SESSION_ID%" : "echo $OPENCODE_SESSION_ID",
+            description: "Print session ID env var",
+          },
+          testCtx,
+        )
+        expect(result.metadata.exit).toBe(0)
+        expect(result.metadata.output.trim()).toBe(sessionID)
+      },
+    })
+  })
+
+  test("exposes OPENCODE_SESSION_TITLE environment variable", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const title = "My Custom Session Title"
+        const session = await Session.create({ title })
+        const bash = await BashTool.init()
+        const testCtx = {
+          ...ctx,
+          sessionID: session.id,
+        }
+        const result = await bash.execute(
+          {
+            command: process.platform === "win32" ? "echo %OPENCODE_SESSION_TITLE%" : "echo $OPENCODE_SESSION_TITLE",
+            description: "Print session title env var",
+          },
+          testCtx,
+        )
+        expect(result.metadata.exit).toBe(0)
+        expect(result.metadata.output.trim()).toBe(title)
+        await Session.remove(session.id)
+      },
+    })
+  })
 })
 
 describe("tool.bash permissions", () => {