read:posts_by_me

Reads the posts the acting account wrote, newest first.

It takes no target - the account being acted as is the subject - which is what makes it its own operation rather than read:posts_by_user pointed at yourself.

Fields
max how many to return, 5 to 100. This is what the call costs
cursor the next from the page before
since_id, until_id only posts newer, or older, than that id
since_time, until_time the same window in time, ISO 8601 UTC
include_replies, include_reposts send false to leave replies, or reposts, out of the page. Left out, everything comes back
With include_replies false, X reaches back through only the account's latest 800 posts, not 3,200
profile whose posts. Optional when the agent has one account
reason Required over MCP. One short sentence, in the agent's own words, for the person

X will not return fewer than five

A max below five is raised to five before the call leaves, and the answer says so, because five is what X returns and what it bills.

What comes back

{ "status": "done",
  "ref": "9L4RC2KF",
  "page": { "next": "7140w5gefhslx3",
            "newest_id": "1832000000000000007",
            "oldest_id": "1832000000000000003" },
  "data": {
    "data": [
      { "id": "1832000000000000007",
        "text": "We rebuilt the pipeline this week.",
        "created_at": "2026-09-15T09:12:44.000Z",
        "author_id": "1400000000000000001",
        "conversation_id": "1832000000000000007",
        "edit_history_post_ids": ["1832000000000000007"],
        "lang": "en",
        "public_metrics": {
          "repost_count": 2, "reply_count": 1, "like_count": 14,
          "quote_count": 0, "bookmark_count": 3, "impression_count": 812
        } }
    ],
    "meta": { "result_count": 5,
              "newest_id": "1832000000000000007",
              "oldest_id": "1832000000000000003",
              "next_token": "7140w5gefhslx3" }
  } }

data.data is always an array and may be empty.

Send newest_id back as since_id

You are then handed only what you have not already paid for. On a feed you sweep regularly that is the difference between a cent a day and a cent a call.