feat: [AI-6949] add session transcript REST endpoint for datamates extension

packages/opencode/src/server/routes/session.ts

@@ -1,4 +1,5 @@
 import { Hono } from "hono"
+import { formatTranscript } from "@/cli/cmd/tui/util/transcript"
 import { stream } from "hono/streaming"
 import { describeRoute, validator, resolver } from "hono-openapi"
 import { SessionID, MessageID, PartID } from "@/session/schema"
@@ -462,6 +463,53 @@ export const SessionRoutes = lazy(() =>
         return c.json(result)
       },
     )
+    .get(
+      "/:sessionID/transcript",
+      describeRoute({
+        summary: "Get session transcript",
+        description: "Retrieve the full conversation transcript for a session as formatted markdown.",
+        tags: ["Session"],
+        operationId: "session.transcript",
+        responses: {
+          200: {
+            description: "Markdown transcript of the session",
+            content: {
+              "text/plain": {
+                schema: resolver(z.string()),
+              },
+            },
+          },
+          ...errors(400, 404),
+        },
+      }),
+      validator(
+        "param",
+        z.object({
+          sessionID: SessionID.zod,
+        }),
+      ),
+      validator(
+        "query",
+        z.object({
+          thinking: z.preprocess(v => v === "false" ? false : v, z.coerce.boolean()).optional().default(false).meta({ description: "Include reasoning/thinking parts" }),
+          toolDetails: z.preprocess(v => v === "false" ? false : v, z.coerce.boolean()).optional().default(false).meta({ description: "Include tool input/output details" }),
+          assistantMetadata: z.preprocess(v => v === "false" ? false : v, z.coerce.boolean()).optional().default(false).meta({ description: "Include assistant model/timing metadata" }),
+        }),
+      ),
+      async (c) => {
+        const sessionID = c.req.valid("param").sessionID
+        const query = c.req.valid("query")
+        const session = await Session.get(sessionID)
+        const messages = await Session.messages({ sessionID })
+        const transcript = formatTranscript(session, messages, {
+          thinking: query.thinking,
+          toolDetails: query.toolDetails,
+          assistantMetadata: query.assistantMetadata,
+        })
+        c.header("Content-Type", "text/plain; charset=utf-8")
+        return c.text(transcript)
+      },
+    )
     .delete(
       "/:sessionID/share",
       describeRoute({

packages/opencode/test/server/session-transcript.test.ts

@@ -0,0 +1,175 @@
+import { afterEach, describe, expect, test } from "bun:test"
+import { Instance } from "../../src/project/instance"
+import { Server } from "../../src/server/server"
+import { Session } from "../../src/session"
+import { MessageV2 } from "../../src/session/message-v2"
+import { MessageID, PartID, type SessionID } from "../../src/session/schema"
+import { Log } from "../../src/util/log"
+import { tmpdir } from "../fixture/fixture"
+
+Log.init({ print: false })
+
+afterEach(async () => {
+  await Instance.disposeAll()
+})
+
+async function withoutWatcher<T>(fn: () => Promise<T>) {
+  if (process.platform !== "win32") return fn()
+  const prev = process.env.OPENCODE_EXPERIMENTAL_DISABLE_FILEWATCHER
+  process.env.OPENCODE_EXPERIMENTAL_DISABLE_FILEWATCHER = "true"
+  try {
+    return await fn()
+  } finally {
+    if (prev === undefined) delete process.env.OPENCODE_EXPERIMENTAL_DISABLE_FILEWATCHER
+    else process.env.OPENCODE_EXPERIMENTAL_DISABLE_FILEWATCHER = prev
+  }
+}
+
+async function addUserMessage(sessionID: SessionID, text: string) {
+  const id = MessageID.ascending()
+  await Session.updateMessage({
+    id,
+    sessionID,
+    role: "user",
+    time: { created: Date.now() },
+    agent: "test",
+    model: { providerID: "test", modelID: "test" },
+    tools: {},
+    mode: "",
+  } as unknown as MessageV2.Info)
+  await Session.updatePart({
+    id: PartID.ascending(),
+    sessionID,
+    messageID: id,
+    type: "text",
+    text,
+  })
+  return id
+}
+
+async function addAssistantMessageWithReasoning(sessionID: SessionID, parentID: MessageID, reasoningText: string) {
+  const id = MessageID.ascending()
+  await Session.updateMessage({
+    id,
+    sessionID,
+    role: "assistant",
+    agent: "build",
+    modelID: "claude-sonnet",
+    providerID: "anthropic",
+    mode: "",
+    parentID,
+    path: { cwd: "/test", root: "/test" },
+    cost: 0,
+    tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+    time: { created: Date.now() },
+  } as unknown as MessageV2.Info)
+  await Session.updatePart({
+    id: PartID.ascending(),
+    sessionID,
+    messageID: id,
+    type: "reasoning",
+    text: reasoningText,
+    time: { start: Date.now() },
+  } as unknown as Parameters<typeof Session.updatePart>[0])
+  return id
+}
+
+describe("session transcript endpoint", () => {
+  test("returns 200 with text/plain markdown for a session", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await withoutWatcher(() =>
+      Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const session = await Session.create({ title: "Test Session" })
+          await addUserMessage(session.id, "Hello world")
+          const app = Server.Default()
+
+          const res = await app.request(`/session/${session.id}/transcript`)
+          expect(res.status).toBe(200)
+          expect(res.headers.get("content-type")).toContain("text/plain")
+
+          const body = await res.text()
+          expect(body).toStartWith("# ")
+          expect(body).toContain("Test Session")
+          expect(body).toContain("## User")
+          expect(body).toContain("Hello world")
+
+          await Session.remove(session.id)
+        },
+      }),
+    )
+  })
+
+  test("returns 404 for a missing session", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await withoutWatcher(() =>
+      Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const app = Server.Default()
+          const res = await app.request(`/session/ses_nonexistent/transcript`)
+          expect(res.status).toBe(404)
+        },
+      }),
+    )
+  })
+
+  test("returns markdown for an empty session (no messages)", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await withoutWatcher(() =>
+      Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const session = await Session.create({ title: "Empty Session" })
+          const app = Server.Default()
+
+          const res = await app.request(`/session/${session.id}/transcript`)
+          expect(res.status).toBe(200)
+          const body = await res.text()
+          expect(body).toStartWith("# Empty Session")
+          expect(body).toContain("Session ID:")
+
+          await Session.remove(session.id)
+        },
+      }),
+    )
+  })
+
+  test("thinking=true includes reasoning, thinking=false and default exclude it", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await withoutWatcher(() =>
+      Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const session = await Session.create({ title: "Reasoning Session" })
+          const userMsgId = await addUserMessage(session.id, "think about this")
+          await addAssistantMessageWithReasoning(session.id, userMsgId, "inner thoughts here")
+          const app = Server.Default()
+
+          // ?thinking=true must include the reasoning block
+          const withThinking = await app.request(`/session/${session.id}/transcript?thinking=true`)
+          expect(withThinking.status).toBe(200)
+          const bodyWithThinking = await withThinking.text()
+          expect(bodyWithThinking).toContain("_Thinking:_")
+          expect(bodyWithThinking).toContain("inner thoughts here")
+
+          // ?thinking=false must NOT include it (validates the z.preprocess fix:
+          // old z.coerce.boolean() coerced "false" string → Boolean("false") = true)
+          const withFalse = await app.request(`/session/${session.id}/transcript?thinking=false`)
+          expect(withFalse.status).toBe(200)
+          const bodyWithFalse = await withFalse.text()
+          expect(bodyWithFalse).not.toContain("_Thinking:_")
+
+          // default (no param) also excludes reasoning
+          const withDefault = await app.request(`/session/${session.id}/transcript`)
+          expect(withDefault.status).toBe(200)
+          const bodyWithDefault = await withDefault.text()
+          expect(bodyWithDefault).not.toContain("_Thinking:_")
+
+          await Session.remove(session.id)
+        },
+      }),
+    )
+  })
+})