diff --git a/src/replay/jsonl-parser.ts b/src/replay/jsonl-parser.ts
index 5060c3451..7faa45391 100644
--- a/src/replay/jsonl-parser.ts
+++ b/src/replay/jsonl-parser.ts
@@ -7,6 +7,10 @@ interface JsonlEntry {
   sessionId?: string;
   timestamp?: string;
   cwd?: string;
+  role?: string;
+  content?: unknown;
+  tool_calls?: unknown[];
+  tool_call_id?: string;
   message?: {
     role?: string;
     content?: unknown;
@@ -78,6 +82,78 @@ function extractToolResults(content: unknown): Array<{ toolUseId: string; output
   return out;
 }
 
+/**
+ * Normalize entries emitted in OpenAI chat-format JSONL (as produced by Hermes,
+ * OpenAI-compatible agents, and other tools that log raw API requests) to the
+ * Claude Code transcript format that {@link parseJsonlText} already understands.
+ *
+ * The OpenAI chat format uses top-level `role` + `content` fields and a separate
+ * `tool_calls` array on assistant messages, with tool results carried in
+ * `role:"tool"` messages. Claude Code uses a `type` discriminator and packs
+ * tool_use / tool_result into structured `message.content` arrays.
+ *
+ * Entries already in Claude Code format (those with `entry.type` or
+ * `entry.message`) pass through untouched.
+ */
+function normalizeOpenAIEntry(entry: JsonlEntry): JsonlEntry {
+  // Already in Claude Code format — leave as-is.
+  if (entry.type || entry.message) return entry;
+
+  const role = entry.role as string | undefined;
+  const content = entry.content;
+
+  // { role: "user", content: "..." }
+  if (role === "user" && content !== undefined) {
+    return { ...entry, type: "user", message: { role: "user", content } };
+  }
+
+  // { role: "tool", tool_call_id: "...", content: "..." }
+  if (role === "tool") {
+    const toolUseId = typeof entry.tool_call_id === "string" ? entry.tool_call_id : "";
+    return {
+      ...entry,
+      type: "user",
+      message: {
+        role: "user",
+        content: [{ type: "tool_result", tool_use_id: toolUseId, content }],
+      },
+    };
+  }
+
+  // { role: "assistant", content: "...", tool_calls: [...] }
+  if (role === "assistant") {
+    const textContent = typeof content === "string" && content.trim() ? content : undefined;
+    const contentArr: unknown[] = [];
+    if (textContent) contentArr.push({ type: "text", text: textContent });
+
+    if (Array.isArray(entry.tool_calls)) {
+      for (const tc of entry.tool_calls) {
+        if (!tc || typeof tc !== "object") continue;
+        const fn = (tc as Record<string, unknown>).function as Record<string, unknown> | undefined;
+        const rawArgs = fn?.arguments;
+        let input: unknown = rawArgs;
+        if (typeof rawArgs === "string") {
+          try { input = JSON.parse(rawArgs); } catch { input = { raw: rawArgs }; }
+        }
+        contentArr.push({
+          type: "tool_use",
+          id: (tc as Record<string, unknown>).call_id ?? (tc as Record<string, unknown>).id ?? "",
+          name: fn?.name ?? "unknown",
+          input: input ?? {},
+        });
+      }
+    }
+
+    // Only restructure if we found something to carry; otherwise leave untouched
+    // so a bare {role:"assistant"} with no content doesn't create a phantom entry.
+    if (contentArr.length > 0) {
+      return { ...entry, type: "assistant", message: { role: "assistant", content: contentArr } };
+    }
+  }
+
+  return entry;
+}
+
 export function parseJsonlText(text: string, fallbackSessionId?: string): ParsedTranscript {
   const lines = text.split("\n").filter((l) => l.trim().length > 0);
   const entries: JsonlEntry[] = [];
@@ -97,7 +173,9 @@ export function parseJsonlText(text: string, fallbackSessionId?: string): Parsed
 
   const observations: RawObservation[] = [];
 
-  for (const entry of entries) {
+  for (const rawEntry of entries) {
+    const entry = normalizeOpenAIEntry(rawEntry);
+
     if (entry.sessionId && !sessionId) sessionId = entry.sessionId;
     if (entry.cwd && !cwd) cwd = entry.cwd;
     const ts = entry.timestamp || new Date().toISOString();
diff --git a/test/fixtures/jsonl/openai-format.jsonl b/test/fixtures/jsonl/openai-format.jsonl
new file mode 100644
index 000000000..ea3c53943
--- /dev/null
+++ b/test/fixtures/jsonl/openai-format.jsonl
@@ -0,0 +1,4 @@
+{"role":"user","content":"Fix the login bug","sessionId":"sess-openai","timestamp":"2026-04-17T10:00:00.000Z","cwd":"/Users/alice/project"}
+{"role":"assistant","content":"Let me check the auth module.","tool_calls":[{"id":"call_1","call_id":"call_1","type":"function","function":{"name":"Bash","arguments":"{\"command\":\"cat src/auth.ts\"}"}}],"sessionId":"sess-openai","timestamp":"2026-04-17T10:00:05.000Z"}
+{"role":"tool","tool_call_id":"call_1","content":"export function login() { ... }","sessionId":"sess-openai","timestamp":"2026-04-17T10:00:06.000Z"}
+{"role":"assistant","content":"Found the bug — missing await on the token refresh.","sessionId":"sess-openai","timestamp":"2026-04-17T10:00:10.000Z"}
diff --git a/test/replay.test.ts b/test/replay.test.ts
index f5dfb9a6e..d5eaf2b74 100644
--- a/test/replay.test.ts
+++ b/test/replay.test.ts
@@ -97,6 +97,51 @@ describe("parseJsonlText", () => {
     const out = parseJsonlText(text, "fb-used");
     expect(out.sessionId).toBe("fb-used");
   });
+
+  it("parses OpenAI chat-format JSONL (role/content/tool_calls)", () => {
+    const out = parseJsonlText(fx("openai-format.jsonl"));
+    expect(out.sessionId).toBe("sess-openai");
+    // user prompt → assistant text+tool_call → tool result → assistant text
+    const kinds = out.observations.map((o) => o.hookType);
+    expect(kinds).toEqual([
+      "prompt_submit",
+      "stop",          // assistant text "Let me check…"
+      "pre_tool_use",  // Bash tool_call from same assistant message
+      "post_tool_use", // tool result
+      "stop",          // final assistant text
+    ]);
+    // user prompt extracted from { role: "user", content: "..." }
+    expect(out.observations[0].userPrompt).toBe("Fix the login bug");
+    // tool_call extracted from assistant.tool_calls[].function
+    const toolCall = out.observations[2];
+    expect(toolCall.toolName).toBe("Bash");
+    expect((toolCall.toolInput as { command: string }).command).toBe("cat src/auth.ts");
+    // tool_result extracted from { role: "tool", tool_call_id, content }
+    const toolResult = out.observations[3];
+    expect(toolResult.toolOutput).toBe("export function login() { ... }");
+    // final assistant text-only message
+    expect(out.observations[4].assistantResponse).toContain("Found the bug");
+  });
+
+  it("does not break Claude Code format when OpenAI entries are mixed in", () => {
+    const mixed = [
+      JSON.stringify({
+        type: "user",
+        sessionId: "sess-mixed",
+        timestamp: "2026-01-01T00:00:00.000Z",
+        message: { role: "user", content: [{ type: "text", text: "claude-format" }] },
+      }),
+      JSON.stringify({
+        role: "user",
+        content: "openai-format",
+        timestamp: "2026-01-01T00:00:01.000Z",
+      }),
+    ].join("\n");
+    const out = parseJsonlText(mixed);
+    expect(out.observations).toHaveLength(2);
+    expect(out.observations[0].userPrompt).toBe("claude-format");
+    expect(out.observations[1].userPrompt).toBe("openai-format");
+  });
 });
 
 describe("projectTimeline", () => {