submit-a-plugin skill: engines example doesn't match get-bb/marketplace entry schema

[yegor-korobeynikov]

What's wrong

The built-in submit-a-plugin skill's "Prepare the entry" section shows this example:

{
  "id": "notes",
  "displayName": "Notes",
  "description": "Keeps project notes beside each bb thread.",
  "icon": { "url": "./icons/notes-1234abcd.svg" },
  "tags": ["notes", "interface"],
  "author": { "name": "Acme", "github": "acme", "url": "https://acme.example" },
  "engines": {
    "bb": ">=0.40.0",
    "bbPluginSdk": ">=0.5.0"
  },
  "source": { "git": { "url": "https://github.com/acme/bb-plugin-notes.git", "range": "^1.2.3" } }
}

The live get-bb/marketplace entry schema (schema/marketplace.schema.json, $defs.entry) declares additionalProperties: false and does not list engines among its properties (id, displayName, description, icon, tags, author, source only). An entry that includes engines fails npm run build / npm run check in the marketplace repo.

How this surfaced

Ran the skill for real across 4 independent plugin submissions this week (get-bb/marketplace#123, #124, #125, #127). Every one hit the same failure independently, because each one followed the skill's own worked example literally before checking the live schema. The skill's own prose says to treat the live marketplace repo as the source of truth over the skill text — but the worked example still shows the stale field, so it's an easy trap even though the skill's own instructions warn against it.

Suggested fix

Drop engines from the worked example in the "Prepare the entry" section (and the "Use this shape as a guide" JSON block), or add a note that engines was removed from the live schema and to always confirm current required/optional entry fields against schema/marketplace.schema.json before writing the entry.

Not filing a PR for this — just flagging, since it wasn't clear which repo canonically owns the skill markdown source (found a copy under apps/server/src/services/skills/builtin-skills/submit-a-plugin/ in a local reference checkout, but no SKILL.md there, only a scripts/ subfolder).

[SawyerHood]

Reproduction & root-cause report: https://get-bb.github.io/reports/issues/2508.html

• Verdict: REPRODUCED · root-cause confidence: high
• Root cause (short): Commit 1e56238 removed marketplace engines fields but did not update the built-in skill or add schema-parity coverage.
• Proposed fix: Remove engines from the skill prose and example. State that package.json owns compatibility. Add a test that validates the example against the schema.
• Caveats: The isolated pnpm install reached the shared inode limit. The prepared dependency tree supported a successful Turbo build. Four reported submission failures remain unverified.

The report has copy-paste repro steps, screenshots where the bug is visual, code permalinks at the base commit, and repro artifacts. It was independently re-run by a second agent (see its Verification section).

AGENT GENERATED: by GPT-5.6-Sol