Proposal

Why

When a delta introduces a capability without a usable ## Purpose, archive writes TBD - created by archiving change <name>. Update Purpose after archive. into the new main spec. Three places already tell authors to replace it — the specs instruction ("including a leftover TBD placeholder — edit the main spec directly"), the sync-specs summary step ("so it gets written now rather than lingering"), and the archive contract itself — but nothing reports that it is still there.

--strict cannot reach it. The check meant to catch a Purpose nobody wrote is a 50-character floor, and the placeholder is 91 characters, so the one rule that exists to catch a thin Purpose is satisfied by the exact text meaning "nobody wrote one". A spec whose Purpose reads Does stuff. fails --strict today; a spec whose Purpose says nothing at all passes.

The result is a capability that carries a to-do indefinitely while every command reports success, and a silent pass is indistinguishable from a clean run. #369 reported agents leaving the placeholder behind and stayed open for seven months; the remedies since have been instructions, which is the mechanism that report described as unreliable.

What Changes

• openspec validate reports a ## Purpose that is still the archive placeholder, as a warning on the spec's Purpose, naming the line to replace.
• The message says to edit the main spec directly, because a ## Purpose in a delta is read only when a capability is created and cannot replace an existing one.
• Detection stays narrow: the sentence archive itself writes counts wherever it appears in the Purpose, and otherwise only a TBD or TODO opening the Purpose counts. A marker inside a sentence is authored prose and is left alone, and so is anything inside a fenced code block, which is a Purpose quoting the placeholder rather than carrying it.
• A Purpose reported as a placeholder is no longer also reported as too brief, so a bare TBD yields one finding rather than two.
• Not breaking: the finding is a warning, so a project that already carries placeholders keeps validating by default and only --strict fails. openspec archive is unaffected — it validates rebuilt specs without --strict, so a spec archive writes still passes the validation it would have passed before.

Capabilities

New Capabilities

None.

Modified Capabilities

• cli-validate: adds a requirement that spec validation report a Purpose left as the archive placeholder, with the severity, detection boundary, and precedence over the existing brevity warning stated as contract.

Impact

• Affected behavior: openspec validate on main specs — validate <spec>, validate --specs, and the bulk/interactive paths that share it. A project carrying a placeholder sees a new warning; under --strict that project now fails until the Purpose is written.
• Unaffected: openspec archive, which validates rebuilt specs non-strictly; delta spec validation, which does not read a main spec's Purpose; and any spec whose Purpose is authored prose.
• Docs: none required — the message carries its own remediation, and the specs instruction already tells authors to edit the main spec directly.