fix(snippets): close the recall-surface gaps found reviewing the Drafter

Four defects from the 2026-07-25 review of the recall (#227) and merge (#231)
milestones. The theme: a snippet could be recorded but not fully corrected, and
the agent and web surfaces had drifted apart.

- #2076 language was mis-derived from the first caller tag, so a snippet created
  with tags and no language read that tag back as its language — corrupting the
  tag set and the code fence on the next update. Only the FIRST tag can carry
  the language, since compose_tags emits [language, "snippet", *caller].
- #2077 MCP update_snippet mapped "" to "unchanged", so no field could ever be
  cleared and no snippet detached from its project. Now an omitted field is left
  alone, an empty string clears, and project_id follows the -1 = detach
  convention. A service-level UNSET sentinel keeps None available as the clear.
- #2078 surface parity: adds delete_snippet (MCP had none, so a wrong snippet
  could not be retired by the agent that recorded it), locations on MCP create
  and update, system_ids through the REST routes and the editor, and the
  near-duplicate gate on REST create with a "record it anyway" escape.
- #2079 project scoping: list_snippets takes project_id through the service, the
  MCP tool and the REST route, defaulting to every project — reaching across
  projects is the point when the helper you need was written elsewhere.

Sharing the list across owners is deliberately NOT in here: query_knowledge is
shared with the Knowledge browse surface, so widening it changes behaviour well
beyond snippets. Left open on #2079 for a scope decision.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLwAaV4DQEmVyn496HnEvt

plugin/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "scribe",
   "description": "Scribe system-of-record for Claude Code: MCP tools over your notes/tasks/projects/rules, a session-start push channel that surfaces your always-on rules + active-project context, process-skills (writing-plans, systematic-debugging, verification, brainstorming, reusing-code), and your saved Scribe Processes auto-surfaced as skills (/scribe:sync). Replaces superpowers + file-memory with one app-backed plugin.",
-  "version": "0.1.14",
+  "version": "0.1.15",
   "author": { "name": "Bryan Van Deusen" },
   "mcpServers": {
     "scribe": {

plugin/skills/reusing-code/SKILL.md

@@ -17,6 +17,9 @@ through recall/auto-inject; this skill is the active reflex around that.
 - About to write a utility, hook, formatter, adapter, or a reusable component?
   **Search snippets before writing it.** `list_snippets(q="…")` (or a plain
   `search`) — a matching one may already exist, in this project or another.
+  `list_snippets` searches every project by default; that's deliberate, since a
+  helper you need here was quite possibly written somewhere else. Narrow with
+  `project_id` only when you specifically want this project's own.
 - If a snippet fits, pull it in full with `get_snippet(id)` and reuse it — its
   `location` points at the reference implementation. Adapt, don't re-derive.
 - If auto-inject already surfaced a snippet title that looks relevant, that's
@@ -37,6 +40,18 @@ through recall/auto-inject; this skill is the active reflex around that.
   per reusable thing. If it already exists, `update_snippet` it instead of
   recording a second copy (the create gate will flag a near-duplicate anyway).
 
+## Keep the record honest
+
+A recorded snippet is offered as prior art on every matching turn, so a wrong
+one costs more than a missing one.
+
+- Details gone stale — a renamed symbol, a moved file, a signature that's
+  changed? Fix it with `update_snippet`. Passing an **empty string** clears a
+  field, so a wrong signature or location can be removed, not just written over.
+- Recorded something that turned out not to be reusable, or that no longer
+  exists? Retire it with `delete_snippet` — it goes to the trash and can be
+  restored. Don't leave it competing for attention.
+
 ## Found the same thing in several places — unify it
 
 When you notice the same reusable thing recorded (or written) as several