fix(docs): publishing guidance states an unqualified 280-character cap despite long-form support #510

Summary

The agent skill's publishing workflow gives a universal 280-character maximum for a POST /2/tweets text payload. The character-counting page also presents 280 as the maximum for Posts generally. Other official documentation describes long-form creation through the same endpoint, so these limits need a scope or eligibility qualification.

Runtime or environment

Documentation source: current default branch main at 5fcfe3da51461ef1c0b59a028da9c365547cad4c; the repository has no published releases. The live skill at https://docs.x.com/skill.md declares metadata version 1.0. Fresh live fetches of the skill, counting-characters page, changelog, and linked customer story preserve the claims described below. No API write or account-entitlement check was executed.

Steps to reproduce

1. Fetch the published skill and read step 1 under ### Publishing a post, then note that step 3 targets POST /2/tweets.
2. Read the opening limit statement at https://docs.x.com/fundamentals/counting-characters.
3. Compare the official changelog's long-form creation announcements at https://docs.x.com/changelog, which describe API creation of long-form Posts and a 25k length.
4. Compare the official-hosted Typefully story at https://docs.x.com/success-stories/typefully, whose publishing section explicitly associates long-form Posts with POST /2/tweets.

These documentation fetches and source comparisons were executed. The skill's cap appears at line 150 in the fetched Markdown. This reproduction concerns contradictory documentation, not acceptance of a particular account's payload.

Expected behavior

The general publishing guidance should distinguish the ordinary Post limit from the separately documented long-form creation capability, with supported eligibility conditions or a pointer to them. It should not imply that every account can create longer Posts.

Actual behavior

The skill says "Compose post text (max 280 characters)" without restricting that cap to ordinary Posts or a stated account entitlement. The counting page likewise states a general 280-character maximum. The changelog documents long-form Post creation and a length of 25k, and the official-hosted customer story identifies the same create-post endpoint as supporting long-form Posts.

Evidence

• Expected source: changelog.mdx, lines 360–367 announces long-form creation; success-stories/typefully.mdx, line 17 contains an official-hosted customer account connecting long-form publishing to POST /2/tweets.
• Failure source: The live skill's publishing step 1 gives the unqualified cap; fundamentals/counting-characters.mdx, line 9 makes the same broad limit statement.
• Evidence provenance: observed
• Local verification: reproduced
• Reproduction completeness: complete

The customer story is attributed documentation evidence, not an independently observed successful API call. The exact account entitlements and acceptance of any particular longer payload remain untested; this report asserts only that 280 is not a universal cap under the documented long-form capability.

Restoration check

Read the publishing and character-counting guidance alongside the long-form creation documentation. Readers should be able to tell which limit applies to ordinary Posts and where to find the conditions for supported long-form creation, without assuming either a universal 280 cap or universal long-form eligibility.

Triage assessment

• Impact level: P2
• Assessment status: provisional
• Impact basis: Agents can reject or unnecessarily split content that falls within the documented long-form capability. No affected account or rejected content was tested.
• Workaround status: unverified
• Workaround basis: The changelog establishes longer-post creation, but the inspected sources do not establish a complete account-eligibility and limit-selection procedure.